# scientific essay about ROLLINGRESISTANCE



## nino (Jan 13, 2004)

in german "MountainBike" they have that all scientific test about rollingresistance. a guy got his diploma on this topic. they measured all sorts of things about rollingresistance and finally we have some scientific numbers and proofs about bike-tires! rollingresistance eats up to 50% of our power so maybe this is a really important topic, right?

which tire width is faster, slim or wide ?
what tire pressures to use
what's the different numbers on different terrain with different pressure?
etc. etc.

to test this they had a bike outfitted with a SRM crank that measures the energy used to pedal. different tire weights have been equaled (they don't state how that was done but they took note of that). same speed on each testrun.

they had a slight uphill with 3 types of terrain parallel to each other.
Tarmac, gravel and soft soil (meadow?)

in the 4 graphs below you see the results of all those intensive testing (over 350 testruns)

strasse = tarmac
wiese = meadow (soft soil)
schotter = gravel

GRAPH 1:
on the left side we have the rollingresistance measured in WATT
bottom is the different soils

we see the Schwalbe Albert Brothers is always the slowest regardless of the soil. note the difference between tarmac, meadow and gravel rollingresistance readings! inetersting to see that the racing Ralph (yellow) is faster than the Fast Fred (grey) on tarmac.
anyway - on soft soil rollingresistance is about 6 times as high as on tarmac.


GRAPH 2:
on the left side we have the rollingresistance measured in WATT
on the bottom we have the tire width in mm (same tire but different widths). all tires tested at the same pressure

note that on tarmac these tires roll almost identical. on gravel the wider tires roll faster. on soft soil the difference becomes most notable. the wider the faster. on soft soil that's a 15,41 watts difference.

GRAPH 3:
on the left side we have the rollingresistance measured in WATT
on the bottom we have the tire pressure in bar

green = soft soil
lower pressure makes for faster rolling!!! 18 watts saved when dropping to 1.5 bar instead of 4.0 bar

red = gravel
slightly less RR when dropping tire pressure

black = tarmac
the higher the pressure is on tarmac the lower the rollingresistance


GRAPH 4:
on the left we have the actual watt output by the testrider
on the bottom we have the time in seconds

this shows the difference of watts needed for the exact same piece on soft soil.
green = Little Albert 54mm wide/ at 4,0 bar
red = Racing Ralph 62mm / 1.5 bar

the difference between these tires: 50 watts !!!! that's for the exaxt same speed and distance.

too bad they didn't test the same tire with different pressure here but 2 completely different tires. the Racing Ralph for sure already rolls dramatically faster than the Little Albert. but it shows what a difference just the correct tire choice and pressure can make. 50 watts is HUGE!!!

final verdict:
old-school thinking with small tires at higher pressure resulting in higher speeds is wrong. that's true on tarmac and dry hardpack only. a wider tire with low pressure isn't dramatically slower but much faster once the trails turn rough and especially if they become humid and soft. there a wide tire is MUCH faster set at the lowest possible pressure. not to speak about comfort and traction too which also helps you go faster.

what about the factor weight?
they measured tires which were 500g heavier (total f+r) and the difference in acceleration was 4,2 watts from 0-25 km/h. only different in acceleration.

the advantage a wider tire has over a skinny one is 15,5 watts and is always an advantage, going slow or fast.

so - i'm interested in the heated debate here as i also have my thought about this topic. there's nothing wrong with ths measurements! i think there's some factors that you could count too but as it is it's a good base.


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## - Jeremy - (Jan 13, 2004)

WOW!

That is amazing. What surprises me the most is the tiny difference in power required to spin heavier tires up to speed. 

I just bought some WTB MutanoRaptor 2.4's and they're HUGE compared to what I usually use. They're still "relatively" light at ~550g, too! I can't wait for the snow to melt in a couple of months so I can try them!

I've also been interested in the new NBX Lite 2.2's. I hope they're a lot wider than the 2.0's. They're not available in the states yet, though 

- Jeremy -


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## Guest (Feb 8, 2005)

*that is a good*



nino said:


> in german "MountainBike" they have that all scientific test about rollingresistance. a guy got his diploma on this topic. they measured all sorts of things about rollingresistance and finally we have some scientific numbers and proofs about bike-tires! rollingresistance eats up to 50% of our power so maybe this is a really important topic, right?
> 
> which tire width is faster, slim or wide ?
> what tire pressures to use
> ...


, i wish US mags did more scientific testing. that old school thought of a skinny high
pressure tire has been gone for a few yrs, as you see the pros switched from slicks
to high volume knobbies. the test i want to see is a group of tires with latex vs the 
same tires UST, same bike and wheels but allow the weight difference you get with
stans to UST. i still feel a true UST tire although heavier rides better and maintains
its momentum better. excellent article though


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## CODMAN (Jan 12, 2004)

Yeah that's interesting Nino! I wish the study was printed in english or french! I must admit that my scientific mind is doubtfull of the testing protocol and how they made for different corrections etc... These are often weak points in studies like these... But that's just my scheptical scientific mind working, and until I can read tests like these for myself, in order to make my own oppinioin of it's value, well... It's definetly a step in the right direction and is at a minimum, very interesting!  

Yes, american Mags should take note and do things like this! But it would probably greatly displease they advertising department...  

Thanks for posting stuff like this for us Nino!

Luego!


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## bhsavery (Aug 19, 2004)

Very interesting. Couple thoughts about this...

First off great test. However I think weight is still a bigger factor than the make. Sure if you were just doing one straight acceleration you might use 4.2watts/500g but keep in mind during a race you're probably doing 3-4 acceleration of 2km/h a minute (I'm just guesstimating here). Point is theres alot of accelerating going on. And of course thats less weight you have to pull uphill.

So on the less pressure/wider issue its clearly a friction problem. They kinda misnamed this test when saying its a rolling resistance test, Its a PEDALING RESISTANCE test. Rolling resistance test would be them sending two identical bikes down a hill with different tires and seeing which went farther. They are pedaling the bikes and measuring how much power it takes to make the bike go a certain speed, so really they're tessting how much grip a tire gets. If I was going to glide down a hill fast I sure as hell would want a skinny tire with a high pressure. Again, in a race, there are times when you'll be gliding down a hill and don't want rolling resistance.

So with the wider, low pressure tires getting more grip, I think its sort of a softness issue. The softer tire can get more mu by "adapting" to grip the terrain where a hard tire will not flex as much and loose grip in spots. This is why a big deal is made about tires that have special compounds that are softer. Of course they usually wear faster.

In short friction is really a double edged sword. What sort of tire pressure/width is going to give you the most grip uphill and least friction downhill. You have to balance them out when you do your tire selections


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## TeXe (Apr 6, 2004)

This is absolutely great info! I've been a fan of big volume and low pressures for a long time, but now we have the scientific proof. Now we only need to wait for the rim manufacturers to realice that we need wider and *light * rims to get the best performance from fat tires. I have a EX721 rim on my play bike and it sure makes bigger tires ride better but I doubt I ever race that rim on anything but on a dh event...

-> -Jeremy-
The casing in the 2,2" NBX Lite is exectly the same size as the casing in the 2,3" NBX, tread is the same as in 2,0 Lite. Check the 2,3's size from here: http://www.mtbtires.com/specs/nokian.html


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## TeXe (Apr 6, 2004)

bhsavery said:


> Very interesting. Couple thoughts about this...
> 
> They are pedaling the bikes and measuring how much power it takes to make the bike go a certain speed, so really they're tessting how much grip a tire gets.


This statement does not make sence. Grip and rollinresistance are different things, though highly related to each other.



bhsavery said:


> If I was going to glide down a hill fast I sure as hell would want a skinny tire with a high pressure.


Again, does not make sence. If you think only about the aerodynamics then yes, but a mountainbiker isn't very aerodynamic recardless of the tire width.

Some more info about the subject: http://www.schwalbetires.com/tire_deflection.html


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## bhsavery (Aug 19, 2004)

TeXe said:


> This statement does not make sence. Grip and rollinresistance are different things, though highly related to each other.
> 
> Again, does not make sence. If you think only about the aerodynamics then yes, but a mountainbiker isn't very aerodynamic recardless of the tire width.
> 
> Some more info about the subject: http://www.schwalbetires.com/tire_deflection.html


Yes you are right, grip and rolling resistance ARE different things, though very related. Let me put it this way. To do this test they put a power meter on a crank and measure the power to needed to make a bike go a certain speed. A more grippy tire will require less power and a less grippy tire will need more because it has less friction.

If you wanted to test simply rolling resistance (aka how easily it rolls) it would be better to simply be gliding and not providing a force.

In regards to the High pressure skinny tire rolling fsater, it will simply because there is less contact area. Clearly when you're going over rocks and stuff thats useless.


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## Ultra Magnus (Jan 13, 2004)

I would have to think that measuring the power required to maintian a certain speed would be an exact way of measuring rolling resistance. What is slowing you? Friction, or rolling resistance of the bike. If the frictional losses in the drivetrain are the same for each test, or within a negligable percentace of each other (same for aerodynamic drag), the only other place you would be getting resistance to movement would be in the tires. Then again, that's only what I think....


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## bhsavery (Aug 19, 2004)

Again that is true! The only thing different slowing you is friction in this test

But these guys are also measuring how efficiently that power from the drivtrain is pushing the bike forward (aka grip of the different tires). If you have a slick tire with no grip its going to take ALOT more power to get to a certain speed.


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## Ultra Magnus (Jan 13, 2004)

I get your point. They are not taking into account for traction, but that would be a differnt test all together. IOW, if your goin up a hill with X tire that has like 1/2 the rolling resistance of Y tire, but X tire can't get any grip but Y tire grips like a mad-dog, then you'd still be better off on Y tire...correct?

I just wish there was a standardized ISO type test that rated tires also accoring to rolling resisance, and after reading this thread, that took into account for surfaces and pressures, so you could make a more educated choice from a selection of tires that fit your traction needs...


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## Motivated (Jan 13, 2004)

*Agree about rim width*



TeXe said:


> This is absolutely great info! I've been a fan of big volume and low pressures for a long time, but now we have the scientific proof. Now we only need to wait for the rim manufacturers to realice that we need wider and *light *rims to get the best performance from fat tires. I have a EX721 rim on my play bike and it sure makes bigger tires ride better but I doubt I ever race that rim on anything but on a dh event...
> 
> -> -Jeremy-
> The casing in the 2,2" NBX Lite is exectly the same size as the casing in the 2,3" NBX, tread is the same as in 2,0 Lite. Check the 2,3's size from here: http://www.mtbtires.com/specs/nokian.html


Manufacturers continue to make narrow rims for XC use when we have all switched over to wider tires. I guess that is an easy way to make low weight. It is my one (and it is significant) criticism of the DTSwiss 4.1 rims - they are narrow. And it is the best feature of Stan's rims (moreso the original 355) - they are wide. As you know tire width is a fuction of rim width. Mount a 2.0 tire on a wide rim and I bet the RR data are equivalent to a 2.1 or 2.25 tire, but with lower weight and better durability.

Also, nino thank you very much for taking the time to scan, translate and post that info. It is very, VERY helpful. Thank you.


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## nino (Jan 13, 2004)

*they are the fastest...*



Mr. Scary said:


> So when are you dropping your NBX Lite 2.0's?


never!
they are the fastest where i ride!
i constantly got 5% better times with it than with other tires. yes, i tested several others before.
that's a point i am a bit sceptical with this test. they test only rolling resistance isolated. you get the result that wider tires on soft soil are faster or that lower pressure is faster offroad BUT that is in general. there are tires that don't roll at all. let's take the Roll-X from Specialized for example who got VERY bad watt readings in earlier tests and comments like "boat anchors".

those tires are wider yet they don't roll at all.hmm....

what i try to say is that as a rule of thumb this results are ok but then we still have tires that are much faster rolling because of different width, carcass, rubber compound and thread design.

for me that means that a wider Nokian NBX will be faster on soft soil, the narrow NBX is faster on hardpack.

lets go further:
in mud we would have wide tires on top, right? the RR might be low BUT what about the grip? skinny tires are mandatory for such conditions....

let's have a look at the RR data below again where the Nokian NBX Lite was tested fastest of all tires. only the Racing Ralph mounted with ECLIPSE Tubelesskit was faster but when tested with inner tube it had 4 watts more RR...

the difference the Nokian has in this test over the competition is pretty much. now imagine using it with a tubelesskit (-4 watt) and much lower pressure...you get the point!

for me it's clear that also the weight plays a big factor. in the test above they neglected any weight advantage but as stated already biking is a constant acceleration/deceleration and therefore mass does count. if you have 500g less to pedal around all the time weight does have an affect too.

anyway - as i already stated in multiple threads before, rollingresistance plays a BIG factor when looking for speed.


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## bhsavery (Aug 19, 2004)

nino, how was that test conducted and what does Durchschlagschutz mean? Google translates as "copy protection"... that can't be right

I think a great test would be to use a test like the first one listed (use a power meter) to find the grip of a tire, and do one like I mentioned, let two bike glide downhill with different tires and see which goes faster/farther. As much as these numbers are meaningful, testing a tire on a treadmill isn't going to translate to real world speed on the trail.


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## Bike Nazi (Apr 3, 2004)

*My studies are more accurate*

I just check out the tire selection on not only the NORBA Pros
but pay special attention to the faster sport and elite level riders
So far my studies have concluded that the racers that are winning appear to be riding skinnier, higher pressure tires.


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## barrows (Jul 6, 2004)

*I dont think so*



Bike Nazi said:


> I just check out the tire selection on not only the NORBA Pros
> but pay special attention to the faster sport and elite level riders
> So far my studies have concluded that the racers that are winning appear to be riding skinnier, higher pressure tires.


Yeah...I think you are wrong. Many pros race on 2.1s at lower pressures. Julien Absalon rode a heavy wide Michelin in front to an Olympic Gold Medal. There is a myth still running around that skinny tires pumped up to 50 psi are fast. It is only a myth. Speed will depend on the course: if it is totally hardpacked with no rough stuff, then skinny semi-slicks pumped up hard will be fast. If the surface has embedded and or loose rocks, roots, and braking bumps, then a wider tire at lower pressures will be better. Of course you need the right wider tire, and you do not want a heavy one either.
This is not anything that new, at the first Olympics Paola Pezzo won Gold on hutch pythons running right around 30 psi, sure now we do not consider Pythons that wide, but back then most pros rode skinny 1.9s at 50 psi.


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## Ultra Magnus (Jan 13, 2004)

I tried airing up my tires (Maxxis Larsen) to 45psi once, because the ground was damp and tacky and I thought the higher pressure would make me faster and I could sacrifice the traction in those soil conditions, but man was I wrong. I couldn't tell really any difference in rolling resistance, but man did it deflect off of every rock that came within a foot of my front tire (not really, but if felt like it). It's like the front tire was trying to jump out from under me and send me into the ground. I won't be doing that again.


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## eurorider (Feb 15, 2004)

nino, have you already tried the NBX Lite 2.2 or is it not yet available?


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## Max (Jan 13, 2004)

I DID! Great allround tire, but weighs in at 540 g! offered really great traction everywhere, but eventually went flat afterriding over nails. however, eclipse might have fixed that, but i was running tubes that day.

the 2.2" roll incredibly fast, that guy on his stupid 50 ccm running full-thorttle couldnt catch me on the flats for more than 1 km! ( i then left for the trails...)

their carcass width is around 53-54 mm if i remember correctly. and they do wear pretty rapidly....


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## nino (Jan 13, 2004)

*no...*



eurorider said:


> nino, have you already tried the NBX Lite 2.2 or is it not yet available?


from what i've heard it's too heavy for my taste. it think something around 550-580g. and i'm so satisfied with my NBX 2.0 that i won't change it too soon...

what also wasn't discussed earlier is that too low pressures make for inacceptable steering precision loss. i'm talking about 1.5 bar settings (21 psi). going straight or climbing is for sure no problem but with such low settings cornering or braking into corners at speed isn't going to be good anymore. so we enter once again into the "grip departement" where low pressure means good grip but too low pressure means loss of control. hmm...


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## eurorider (Feb 15, 2004)

yea, I can't wait to try the NBX Lite 2.0 ...will be going from the twister SS/fast fred light 2.0 to these so I'm very excited ...I think my speeds in the singletrack are going to change  

I only bought one so far and it came in at 444g which is the lightest I have heard of  

are there no world cup riders on these tires??

did Frischy ever go for a spin on them?


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## nino (Jan 13, 2004)

*Ritchey...*



eurorider said:


> yea, I can't wait to try the NBX Lite 2.0 ...will be going from the twister SS/fast fred light 2.0 to these so I'm very excited ...I think my speeds in the singletrack are going to change
> 
> I only bought one so far and it came in at 444g which is the lightest I have heard of
> 
> ...


he has to use "Ritchey" tires. well, currently he is experimenting with Dugast tubulars but those have Ritchey tread on top too. only the insiders can tell the difference though. they look like any Ritchey tire.
by the way - those tubulars Frischi uses are exactly as decribed above:
WIDE and he runs them ULTRASOFT...guess why?


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## dovid (Apr 8, 2004)

Now, I always though gazzi 3.0 were a good idea...

Are NBX's fragile? How about cost compared to RRalph?
I sliced my rear RRalph on my first ride (2.4km long! I think it was a fluke), and it's still rideable (patched), and I don't want to have to pay for a replacement.


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## Boj (Jan 13, 2004)

Great work, Germans and Nino.

I've been looking for these answers for a looooong time. It really puts in better perspective how rolling resistance actually behaves offroad. Wider tires = less rolling resistance has always been the case, even in the textbooks, but rolling resistance dropping so much with progressivly lower pressure. Amazing and exactly the opposite to the textbooks.

I worked last year on trying to find optimum air pressure. I speculated that loss of suspension effect of tires (on a miniature, inperceptible level) with increasing air pressure manifested itself as increased rolling resistance. I developed a Matlab model to prove this and even performed my own tests on a downhill to establish relationship between the tire pressure are RR but was ultimately unsuccessful. I would have killed for this kind of info a year ago and was planning to buy a Power Tap, amongst other things, to measure these exact things.

*What speed did they test the tires in each test and did they publish what the combined weight of rider + bikes were for each test case?*

I always knew rolling resistance is much more important than weight but this latest instalment makes me think that I should not care at ALL about tire weight so long as they are proven to roll well. Although it is clear what pressure you should run the tires, at the moment all rolling resistance data we have is in form of tests run on a smooth treadmill which still leaves open the question of whether to select wider tire with poorer tradmill rolling properties or skinnier tire with good RR on smooth? Well at least Germans left something for me to mull over.

With this new data it is realistically possible that Nokian NBX Lite 2.0 is not the tire of choice as far as RR is concerned thanks to such small width.


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## bhsavery (Aug 19, 2004)

*Hold the phone here*



Boj said:


> Great work, Germans and Nino.
> 
> I've been looking for these answers for a looooong time. It really puts in better perspective how rolling resistance actually behaves offroad. Wider tires = less rolling resistance has always been the case, even in the textbooks, but rolling resistance dropping so much with progressivly lower pressure. Amazing and exactly the opposite to the textbooks.
> 
> ...


Couple things. First off I don't think riding through a "soft meadow" is a good indication of anything, anyone who's ridden through a field before will tell you its the least effiecient surface to ride through, barring soft sand maybe. So wide tires with more traction are going to show a MUCH lower wattage in this type of test. I'm just saying how often do you ride through a field? I think somewhere between the gravel and meadow is right for a real world surface, probably closer to gravel.

Anyway I'd submit that that the wattage doesnt drop that much in respect to pressure. Keep in mind that sane mt bikers ride 30-45 psi (2-3 bar) so not too much of that graph is aplicable. And over that range the wattage drops 6.8w in the "meadow" and 2.6w on the gravel. Something to think about.

As I said before I think this test has alot more to do with traction, but if you don't think so, convince me why. Defenitely an interesting test though.


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## Cloxxki (Jan 11, 2004)

Very nice data, thanks Nino!

Now imagine, adding 300g to your bike by going to the next larger rim size, and in return seeing your rolling resistance drop by 10% in each and every circumstance. Good trade-off? I think it is


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## nino (Jan 13, 2004)

*traction has no affect here...*



bhsavery said:


> Couple things. First off I don't think riding through a "soft meadow" is a good indication of anything, anyone who's ridden through a field before will tell you its the least effiecient surface to ride through, barring soft sand maybe. So wide tires with more traction are going to show a MUCH lower wattage in this type of test. I'm just saying how often do you ride through a field? I think somewhere between the gravel and meadow is right for a real world surface, probably closer to gravel.
> 
> Anyway I'd submit that that the wattage doesnt drop that much in respect to pressure. Keep in mind that sane mt bikers ride 30-45 psi (2-3 bar) so not too much of that graph is aplicable. And over that range the wattage drops 6.8w in the "meadow" and 2.6w on the gravel. Something to think about.
> 
> As I said before I think this test has alot more to do with traction, but if you don't think so, convince me why. Defenitely an interesting test though.


traction absolutely has no affect in this test as well as the wind resistance. the slight uphill didn't demand for any "traction" and the constant speed was just 9.5 km/h. so it's definitely pure "friction" that need to be overcome. therefore they measured the wattage needed at the cranks.

over here in europe many races are held on "meadow" style terrain. anyway - all this wants to show is the effect different terrain has on rollingresistance.

1st: a wider tire rolls faster the "deeper" the terrain becomes
2nd: lower pressure lowers RR in loose conditions

add 1 and 2 and you most probably get a bigger decrease in RR than just 2 watts. as i already stated many, many times just switching to the Nokian NBX Lite has made me 5% faster! that's 3 minutes per hour just because of the lower RR the NBX has!

now i just have some thoughts about this test as it really isolates the RR but doesn't factor in weight and brand/type of tire.
they say the weight difference of a 500g heavier setup is just 4 watts in acceleration /once from 0 up to 25 km/h = 15 miles) BUT how many times per hour do we actualy accelerate? and how many times do we have to deccelerate where more mass means longer braking, you need to push these 500g all the time, not just when accelerating, and you also feel those 500g when you have to carry your bike /those doing long distance marathons in the alps know what i'm talking about).

so while point 1 and 2 from above may be correct as a general rule of thumb it doesn't say any 2.4" tire is faster than a 1.9" tire in loose soil.

i already started doing some "testing" using analyticcycling.com to see what effect 500g more weight have. i mean, how many watts do you need to carry 500g more? so maybe a lightweight skinny tire set at low pressure is still faster overall than a heavier wider tire depending on the brand/type of tire.


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## Guest (Feb 9, 2005)

*ninokian*

what pressure do you run in those, and can you post a pic so i can see how wide
they are mounted?


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## barrows (Jul 6, 2004)

*Balance*

It seems to me that these tests show the need to balance out all the factors to find the fastest combination of tread pattern, tire width, and pressure applicable to a given course. I ride and race (endurance events only) in Colorado. The terrain is usually a mix of hardpack with a loose top layer, many embedded rocks, some roots, and some sections of loose rock. I weigh 165 lb. and a tire like the NBX lite 2.0-which is really narrow, is too small for me in this terrain. I find the usual best balance of RR, traction, and control is with tire pressures around 34-38 psi rear and 30-32 psi front. I run Stan's with regular tires. The NBX lite 2.0 wouldn't provide enough rim protection or volume to deal with the roughness of the terrain under my weight. I would love to try the NBX lite 2.2, but cannot find them. I am thinking a Racing Ralph 2.25 may be the way to go, they are light at something around 520 gm, so only 100 per pair more than a skinny NBX lite 2.0 or 2.0 Pythons, etc. Or I could run a 2.1 Racing Ralph rear with a 2.2 front. Sorry I am digressing, but I find thinking about these issues fascinating.
My experience has proven to me that in my terrain a larger volume tire run around 30-36 psi is the fastest overall. Of course I am only considering fairly fast tread patterns and rubber compounds as well.
Thanks Nino for posting this information and getting this discussion going. I am getting excited to test different tires myself when the snow melts.


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## bhsavery (Aug 19, 2004)

absolutely, theres so many tire choices/variables, I suppose with unlimited time/money one could find the best tire for each terrain, but its all about finding the best fit overall.

I'd like to see them test different tire compounds as well, in a looser terrain a softer tire will achieve similar results as lowering air pressure, due to it being able to adapt to the ground. I think this is part of the reason NBX lites are fast. (I use them too btw, but would be willing to try a bit wider)

Anyway traction does come into play. Becuase the way they are measuring the power expended at the pedals, on a tire with little traction some of that power is going to be expended spinning the tire, etc rather than pushing the bike forward. Wouldnt you agree a tire with less traction needs more power to maintain a given speed????


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## nino (Jan 13, 2004)

*traction is negligible here...*



bhsavery said:


> absolutely, theres so many tire choices/variables, I suppose with unlimited time/money one could find the best tire for each terrain, but its all about finding the best fit overall.
> 
> I'd like to see them test different tire compounds as well, in a looser terrain a softer tire will achieve similar results as lowering air pressure, due to it being able to adapt to the ground. I think this is part of the reason NBX lites are fast. (I use them too btw, but would be willing to try a bit wider)
> 
> Anyway traction does come into play. Becuase the way they are measuring the power expended at the pedals, on a tire with little traction some of that power is going to be expended spinning the tire, etc rather than pushing the bike forward. Wouldnt you agree a tire with less traction needs more power to maintain a given speed????


as you can see in the pic below traction definitely didn't play a factor here.
you see: 
1 meadow
2 gravel
3 tarmac

me too i wouldn't say no to a wider NBX but it would have to weigh the same. nevertheless i might try the 2.2 too just to see how it performs. on a HT it might give you some extra comfort. but then i would keep the slim 2.0" up front as most of the weight is in the back anyway and we all have suspension in the front so no need for extra comfort there.

by the way: 
i use 39 psi (2.7 bar) pressure in my NBX. that's what i found to be the best compromise of good grip and perfect steering control. any lower and i don't feel comfortable at speed.


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## Chester (Jan 15, 2004)

*Readers are "thinking" what they want to think*

This is more great information from Nino. Many thanks.

However reading the replies, it appears that most readers are just trying to use the information to back up what they previously believed. Fat tire lovers, say......Look, I was right all along....Low pressure fat tires are best.....and comfy....

I believe most riders delude themselves as to the true conditions they ride in.
Oh, they'll talk about all the mushy, soft loose stuff they ride in, but any unbiased observation of the actual conditions would find that during 7 months of the year, 85% of their mileage is being run on fairly dry, fairly hard track.......with some dust, loose bits thrown in.
Yet these riders will focus on the few difficult sections that require the most in tire gripping etc. That is OK, but your overall time will be mostly affected by the other 85% of the course where the tires similar to Nino's NBX 2.0 lights, running at between 35 and 40 psi will simply run faster.
No amount of extra speed or ease on the difficult 15% of the cross country course will make up for the time lost on the 85%.
Take a close look at the entire course you run. Don't ignore the easy parts where you really fly, because rollling resistance on those sections is just as important as on those much smaller technical sections you focus on.
Its the time at the end of the course that counts, not how fast you do a few soft, messy sections.

Once again, I see almost everyone just trying to believe what they already believed prior to reading this new study. Picking out the parts that agree with your previous bias.


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## Chester (Jan 15, 2004)

*Those conditions simply don't exist here*



nino said:


> as you can see in the pic below traction definitely didn't play a factor here.
> you see:
> 1 meadow
> 2 gravel
> ...


Lets see, most people I know ride about .001 of the time in #1 meadows and try to avoid #2 gravel 99% of the time, and only ride #3 tarmac getting to and from the trail. But they will use these tests to allow their thinking about tires to go along with what makes them comfortable rather than what makes them fast.
They like softer, wider, more comfortable tires and will use this study to back up their prior conclusions.
I'm guessing that about 90% of them would do faster times on your 39 psi Nokians, but they will now use "meadow" and "gravel" tests to show they should use Roll-X Pros at 30 psi......even though they may go from March to October without ever pedaling through even one soft green meadow.
Don't the Germans still have plain old "dirt" in some sections of the country?


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## Bike Nazi (Apr 3, 2004)

*My point is you don't have to spend a lot of time or money*



barrows said:


> Yeah...I think you are wrong. Many pros race on 2.1s at lower pressures. Julien Absalon rode a heavy wide Michelin in front to an Olympic Gold Medal. There is a myth still running around that skinny tires pumped up to 50 psi are fast. It is only a myth. Speed will depend on the course: if it is totally hardpacked with no rough stuff, then skinny semi-slicks pumped up hard will be fast. If the surface has embedded and or loose rocks, roots, and braking bumps, then a wider tire at lower pressures will be better. Of course you need the right wider tire, and you do not want a heavy one either.
> This is not anything that new, at the first Olympics Paola Pezzo won Gold on hutch pythons running right around 30 psi, sure now we do not consider Pythons that wide, but back then most pros rode skinny 1.9s at 50 psi.[/by the way:
> 
> studying fast, just copy someone who is.
> ...


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## macsi (Dec 3, 2004)

Chester said:


> Don't the Germans still have plain old "dirt" in some sections of the country?


It's almost a cultural problem: every MTB trail is built to perfection! You are not allowed to use any "plain old dirt". Medow means a kind farmer let cyclists use his land, that otherwise would be used by cows. Gravel means the region built a trail for MTBs. Tarmac is to connect the "difficult" 500 meter sections...

My country is not so rich, but at least you can ride MTB where ever you like.. almost 

-b


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## undertrained (Jan 12, 2004)

*How does notubes affect RR?*

Still on the fence about goop in the tires vs tubes. Is there a difference in rolling resistence and if so how much?


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## jcw (Dec 31, 2003)

*Similar aritcle*

Road bike related, but similar to this thread. Another example of lower tire pressure being faster. This from Lenord Zinn's column on Velo New's web site last week:

PSI too high? 
Dear Lennard, 
I've been reading some of Zipp's comments on tire pressure and rolling resistance attached below. When you really sit down and talk to them about tire pressure they're recommending pressures of 100-120psi (sometimes less) depending on the tire, casing, and environment. I am including comments from Josh at Zipp on this topic. One thing I quickly noticed was the absence of weight in his recommendations. A larger rider running 120 psi compared to a lighter individual (say 30 pounds difference) would exhibit a larger contact patch (resistance or traction however you look at it) due to weight so I'm really not jiving on his basic psi recommendations.

Leaving road conditions out (rain, etc.) what are your thoughts on tire pressure? The common theme of tubulars is the advantage of both weight and tire pressure. The ability to run pressures of 180-200 psi. I know for myself I feel faster (have never tried to test this with rollouts or anything) when running pressures of 140-160 psi (clincher) and 180-200 psi (tubular). I've ridden a number of tires and prefer the ride of higher psi tires such as Vittorias, Vredestein and Tufos.

Do you know of any numbers or tests that prove these thoughts on tire pressure? I've had a number of lengthy conversations with Biomechanists interms of rolling resistance (friction) and don't know how a general recommendation on lower pressures can be faster especially not taking weight into account. It goes against everything I've read about rolling friction. It's pretty easy to point out that the average pro in the peloton only weighs about 150 lbs., so of course it's common sense that they wouldn't need to run similar pressures as you or I, but 100-120 psi seems a bit low when you're talking tire pressure for the most efficient rolling resistances.

I've also been reading your blurbs about tubulars, Tufo and their clincher tubulars. Taking Zipp's tire pressure recommendations in mind where do you stand in regards to Tufo and their clincher tubies and other high pressure tires? 
Tom

Dear Tom, 
I agree with Josh, and yes, there are lots of test numbers to back it up. It is the same reason a suspension bike (or car) is faster over rough ground - less mass must be accelerated when bumps are encountered, thus saving energy and reducing momentum loss. Every little bump that gets absorbed into your tire (another reason that supple, handmade casings roll faster than stiffer, low-thread-count casings) is a bump that does not lift the entire weight of you and the bike.

You feel fast on a rock-hard tire for a similar reason that people like the feel of stiff brakes (V-brakes with the levers set on low leverage). The brake feels good and stiff because you are doing more of the work. If you increase the leverage, the brake feels spongy, because the extra mechanical advantage allows a modest pull to squish the pads.

When you ride a tire at 170psi, the bike feels really lively and fast. That is because you are being bounced all over the place by the surface roughness of the road. However, every time you are bounced, energy you applied to the pedals to get you up to speed is lost. Also, you have less control of the bike, so it feels like it is going faster, even though it isn't. Ever notice how driving down the highway at 75mph in an old Jeep feels crazy fast, and you can cruise smoothly along at 100mph in a nice Saab or BMW and feel like you are going maybe 60mph unless you are looking at stationary objects passing by?

There is simply no question about it; rolling resistance tests conducted with bicycle tires rolling over surfaces akin to normal road surfaces always indicate the lowest rolling resistance at pressures a lot closer to 100psi than to 170psi! Years ago, for example, I saw results like this at the Continental tire factory. I was told of similar results at a number of other tire factories I have visited. 
Lennard


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## Smiker (Apr 15, 2004)

*Wider rims ARE a Good Thing, IMHO*



TeXe said:


> . Now we only need to wait for the rim manufacturers to realice that we need wider and *light * rims to get the best performance from fat tires. /QUOTE]
> 
> I've just moved to a new bike, but my old one had Mavic F519's. No, they weren't particularly light, but they were ultra tough (a good wheel build helped of course) and their extra width made a lot of tyres I hadn't liked previously, a joy to ride. Hutchinson Pythons ended up being my favourite, as they have a fairly generous bag anyway.
> 
> ...


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## nino (Jan 13, 2004)

jcw said:


> Dear Tom,
> I agree with Josh, and yes, there are lots of test numbers to back it up. It is the same reason a suspension bike (or car) is faster over rough ground - less mass must be accelerated when bumps are encountered, thus saving energy and reducing momentum loss. Every little bump that gets absorbed into your tire (another reason that supple, handmade casings roll faster than stiffer, low-thread-count casings) is a bump that does not lift the entire weight of you and the bike.
> 
> You feel fast on a rock-hard tire for a similar reason that people like the feel of stiff brakes (V-brakes with the levers set on low leverage). The brake feels good and stiff because you are doing more of the work. If you increase the leverage, the brake feels spongy, because the extra mechanical advantage allows a modest pull to squish the pads.
> ...


well- i'd say Lennard should go back to the drawing board!
no one is using road tires at 100 psi excepty maybe at the classic races that go over cobblestones where the pros use extra-wide tires to fight pinchflats and get some comfort.
ALL test, including the one i posted initially, show a DECREASE with HIGHER PRESSURE on tarmac. and on a roadbike you definitely can feel those couple of watts that are lost as the speeds you reach are more constant. it's pretty easy to tell the differences on a roadbike.

BUT the myth about tubulars rolling faster and beeing "better" is fading slowly anyway. german roadie magazine TOUR tested several tubulars just last year and along RR measurements thea also took note of several other factors. TUFO tires showed the worst RR of all tubulars. that's because of the way they are made. italian tubulars like Gommitalia and Veloflex are fastest but have no puncture protection and loose air quite fast (latex inner tubes).

but once again higher pressure drops RR by a few watts PER TIRE! and a Conti GP 3000 that was tested alongside with regular butyl inner tube placed well in the middle of this tubular test as far as RR was concerned! by the way: the GP 3000 is a good all around clincher tire but definitely not a fast rolling one. in the actual french "Le Cycle" roadie magazine they tested 50 different clinchers and they also did a comparison of RR. they didn't use a treadmill but mounted each tire on a bike that was installed on a hometrainer. they tested how far a tire still rolled until it stopped coming from a certain speed.
that sounds pretty realistic too as the main force stopping the wheel is the RR (and some friction of wheel bearings and chain).

see these results below where the Conti GP 3000 placed 33rd (27.9m)! strange but true, the Tufo CLINCHER was fastest here (41.7m). so they can make some fast tires (clinchers!!) but look at the weight: 230g....ouch! and the tubular technique they use isn't getting them up to speed as shows the TOUR test above.

you bet my next clincher i will test on my roadbike is the Vittoria Ultraspeed (4th place at 39.6m). at 157g it's almost as light as the Conti Supersonic i usually use but is definitely faster and will be more durable too.

anyway - in the tubular-test of TOUR magazine the difference between fastest and slowest tubular tire was worth 1.5 km/h in the real world. they tested with a preofessional rider on a wooden indoor track with SRM crank and at a given wattage the faster tire was making for 1.5 km/h more speed (= 1 mile/h). 42.5 instead of 41 km/h at what i recall 300 watts rider input.


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## Max (Jan 13, 2004)

i would highly doubt the validity of the french tire RR test. with temps below 0°C and ice ans snow on the streets you can guess i spend quite a lot time on my Tacx Grand excel.
for those who dont know in trainers, the Tacx is a rear wheel trainer with a digital display and adjustable wattage+slope.
what i have found out is that with the changing pressure of the trainer against the tire, the wattage in relation to my heart rate changes as well. so that means, that even half a turn on the adjuster knob increaes the RR dramatically. so if they just swapped out the tires - and there was a slight change in the effective tire diameter, that could already have an high impact on the measured RR.

of course the tufo c elite jet is still a faster tire than the schwalbe stelvio rain, but i wouldnt diss a tire only because the "roulage" (as the french would call it) differs from another tire by a slight margin of 1 m or so.

just a side note that one should consider reading these tests. it would be more valid to use the same wheel, with different tires and 8 bar pressure for a 23 mm tire (narrower tires with slightly higher pressure), and put a constant load of 70 kg onto the wheel. i know continental uses a similiar testing machine


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## TeXe (Apr 6, 2004)

Chester said:


> This is more great information from Nino. Many thanks.
> 
> However reading the replies, it appears that most readers are just trying to use the information to back up what they previously believed. Fat tire lovers, say......Look, I was right all along....Low pressure fat tires are best.....and comfy....
> 
> ...


Blaah, you are ruining our joy!  But you have some truth in there.


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## nino (Jan 13, 2004)

*that's what they did...*



Max said:


> just a side note that one should consider reading these tests. it would be more valid to use the same wheel, with different tires and 8 bar pressure for a 23 mm tire (narrower tires with slightly higher pressure), and put a constant load of 70 kg onto the wheel. i know continental uses a similiar testing machine


that's exactly what they did. the overall weight, resistance etc etc. were adjusted each time they put a new tire on. all beeing equal i think this has some validity although the differences sure can't be taken to the real world outside 1:1.
tires got tested at the manufacturers recommendated pressures. (just as an example: the Tufo at 10 bar, the Vittoria at 9, the Conti Supersonic at 8, Conti GP 3000 at 8.5....)


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## nino (Jan 13, 2004)

*almost 4 watts less per tire!*



undertrained said:


> Still on the fence about goop in the tires vs tubes. Is there a difference in rolling resistence and if so how much?


using a tubelesskit saves almost 4 watts per tire compared to butyl inner tubes. just have a look at the RR data i posted in this thread where the absolutely fastest was a Schwalbe Racing Ralph mounted with ECLIPSE Tubelkesskit (green coloured). that same tire tested with inner tube like all others had 4 watts more RR.
here you get the proof that the "goop" actually drops RR by almost 8 watts!


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## barrows (Jul 6, 2004)

*Riding Surface*



nino said:


> using a tubelesskit saves almost 4 watts per tire compared to butyl inner tubes. just have a look at the RR data i posted in this thread where the absolutely fastest was a Schwalbe Racing Ralph mounted with ECLIPSE Tubelkesskit (green coloured). that same tire tested with inner tube like all others had 4 watts more RR.
> here you get the proof that the "goop" actually drops RR by almost 8 watts!


It is interesting that these tests are not taking into account the effect that riding surface has on RR. The beginning of this thread re MTBs was all about how different riding surfaces responded to changes in pressure and width. The same factors affect road tires as well. On the road issue I agree with Lennard Zinn's observations. The tests that Nino has posted on road tires are all done on a hard smooth surface, not a road. There is a reason why road pros run pressures around 110-120 psi on the road. And track riders, running on a much smoother surface run much higher pressures, and skinnier tires as well. This difference is the same difference pointed out by the mtb tests that show lower pressures and wider tires are faster on rougher surfaces.
Here is why: Imagine a 1.95" mtb tire pumped up to 50 psi rolling along on hardpacked dirt that is smooth, I believe we can realize that this would be fast. Now imagine the same tire rolling along hardpacked dirt embedded with rocks that stick up an inch from the top of the surface. When the tire is hard and narrow, with little volume, everytime it hits an embedded rock it rises up to roll over the rock, when it rises up, forward momentum is converted to upward momentum, and to maintain the same speed, more force must be applied. Now imagine a 2.1 tire with some volume, running at 34 psi, hopefully this is also a high quality tire with a supple casing, when it hits the embedded rock, the tire deforms a little, and then reforms as the rock comes out the other side, the wheel does not rise up as much, and more forward momentum is conserved. As for the road tires, next time you are at a velodrome put your face down on the surface of the track at take note of how smooth it is, then inspect an asphalt road the same way. The difference is obvious, and so the need for wider tires with lower pressures on the road vs. the track.


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## nino (Jan 13, 2004)

*wrong...*



barrows said:


> It is interesting that these tests are not taking into account the effect that riding surface has on RR. The beginning of this thread re MTBs was all about how different riding surfaces responded to changes in pressure and width. The same factors affect road tires as well. On the road issue I agree with Lennard Zinn's observations. The tests that Nino has posted on road tires are all done on a hard smooth surface, not a road. There is a reason why road pros run pressures around 110-120 psi on the road. And track riders, running on a much smoother surface run much higher pressures, and skinnier tires as well. This difference is the same difference pointed out by the mtb tests that show lower pressures and wider tires are faster on rougher surfaces.
> Here is why: Imagine a 1.95" mtb tire pumped up to 50 psi rolling along on hardpacked dirt that is smooth, I believe we can realize that this would be fast. Now imagine the same tire rolling along hardpacked dirt embedded with rocks that stick up an inch from the top of the surface. When the tire is hard and narrow, with little volume, everytime it hits an embedded rock it rises up to roll over the rock, when it rises up, forward momentum is converted to upward momentum, and to maintain the same speed, more force must be applied. Now imagine a 2.1 tire with some volume, running at 34 psi, hopefully this is also a high quality tire with a supple casing, when it hits the embedded rock, the tire deforms a little, and then reforms as the rock comes out the other side, the wheel does not rise up as much, and more forward momentum is conserved. As for the road tires, next time you are at a velodrome put your face down on the surface of the track at take note of how smooth it is, then inspect an asphalt road the same way. The difference is obvious, and so the need for wider tires with lower pressures on the road vs. the track.


just go back to the initial post and have a look at the results on tarmac. you can clearly see that narrow tires roll faster than wide ones (not by much but they are faster) and that higher pressure on tramac drops RR.

there is a certain point where raising the pressure more doesn't result in any valuable RR loss but makes for an uncomfortable and springy ride. Pros run 23mm tires because they spend 6-8 hours in the saddle. have a look at what they run when they do a time trial where all that's needed is speed....


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## bhsavery (Aug 19, 2004)

Barrows I completely agree. and I think the results actually back it up. Barrows is saying on a smoother surface, more pressure is ok because the tire doesn't need to "flex and adapt" as much to stay on the surface and absorb shock, and yields lower contact area --> less friction. 

The tarmac results over varying pressure shows this too be true. Of course these are for mtbike tires on a road. With road tires the optimal point for comfort/cornering as nino said is more like 23mm


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## macsi (Dec 3, 2004)

bhsavery said:


> With road tires the optimal point for comfort/cornering as nino said is more like 23mm


Road bike tire pressure all depends on the quality of the road surface. At the Paris-Roubaix most racers use 25-27 mm wide tires and low pressure (60-80 psi). Most of the punctures that happen on the cobbles are due to very low tire pressure. What pressures do cyclocross racers use? Incredibly low! Our national champion ran 30 psi on a muddy/snowy course in the 35 mm tires.

In my country we have very bad road infrastructure, I usually ride 5-6 hours, so I use 25 mm tires and 80-90 psi. I used to run 27 mm tubulars at 60-70 psi. I weight 73 kgs/170 lbs. When I go riding in Austria, I put on 23 mm tires and run 100-110 psi. Actually, above 100 psi there is little improvement in RR - only a few watts, but on a long ride comfort is very important...

-b


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## Chester (Jan 15, 2004)

*Once again, delusional mtn biker analysis of actual surface*



barrows said:


> Here is why: Imagine a 1.95" mtb tire pumped up to 50 psi rolling along on hardpacked dirt that is smooth, I believe we can realize that this would be fast. Now imagine the same tire rolling along hardpacked dirt embedded with rocks that stick up an inch from the top of the surface. When the tire is hard and narrow, with little volume, everytime it hits an embedded rock it rises up to roll over the rock, when it rises up, forward momentum is converted to upward momentum, and to maintain the same speed, more force must be applied. Now imagine a 2.1 tire with some volume, running at 34 psi, hopefully this is also a high quality tire with a supple casing, when it hits the embedded rock, the tire deforms a little, and then reforms as the rock comes out the other side, the wheel does not rise up as much, and more forward momentum is conserved. .


As ususal, mtn bikers are always using this example about all those 1 inch rocks sticking up all over their routes/trails.
A real scientific analysis would show that very few 1 inch or greater rocks are sticking up on their path....
You just think they are under your tire on every rotation, but if you closely observed you would see they are quite spread out over your entire run. The percentage of your riding that is negatively impacted by the type of surface you are focusing on is well under 15% in most intstances....
So you are choosing a tire to perform better on that 15% rather than what is best for the other 85% of your run. Everyone always focuses on the small difficult sections and picks tires that will enable them to go fast their, even though those same tire and pressures will be much slower on the other 85% of their course.

Mtn bikers are delusional in this regard. Sure, the wider, lower pressure tire is more comfortable, but stop fooling yourself it is gonna be faster on any but the most extreme conditions........Like wet meadows, or miles of gravel, or places where 1 inch rocks are protruding every 12 inches and can't be avoided.
Take a real look at where you are riding and assign a percentage to that which is smooth, that which is hard, that which is soft and wet, and that which is full of rocks that you are trying to go over at hight speed......( not some rock garden, you are doing technical skills on at 3 mph)
Look at the whole picture.......not at some diffcult spoonful of the cross country course.

People will do almost anything to twist the results to fit their prior bias about this rolling resistance/tire pressure issue.........almost always forgetting all the positive effects that they get on the other 85% of the course where the race will actually be won or lost. The final time at the finish like is the only true measurement, not how fast you negociated some sloggy wet meadow or some 500 meter gravel section.


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## nino (Jan 13, 2004)

*agreed...*



Chester said:


> As ususal, mtn bikers are always using this example about all those 1 inch rocks sticking up all over their routes/trails.
> A real scientific analysis would show that very few 1 inch or greater rocks are sticking up on their path....
> You just think they are under your tire on every rotation, but if you closely observed you would see they are quite spread out over your entire run. The percentage of your riding that is negatively impacted by the type of surface you are focusing on is well under 15% in most intstances....
> So you are choosing a tire to perform better on that 15% rather than what is best for the other 85% of your run. Everyone always focuses on the small difficult sections and picks tires that will enable them to go fast their, even though those same tire and pressures will be much slower on the other 85% of their course.
> ...


all i can say is that the supplied data is nice to know just in case you do have such conditions maybe in the future....

my own testing with stopwatch revealed the Nokian NBX as the fastest tire by far. i have pretty mixed terrain, some technical dh sections but overall my times got faster by 5%. sure there are tires with more comfort (wider) or better grip (especially in mud) or better puncture resistance or more durable etc...but for my style of riding and terrain the NBX with ECLIPSE Tubelesskit beats them all when speed counts!


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## Ultra Magnus (Jan 13, 2004)

Depends where you live/ride. Here in the desert, maybe 1/4 of my normal XC loop is smooth hardpack. The rest is long sections of 1" rocks, and gravel, and sand. I've compared average speeds between 4 XC loops I've ridden on with friends. In Big Bear, on the (I think) grout bay loop, we averaged around 8.5 mph with lots of stopping. On our two honda valley loops (differnt loops, same area) we still averaged more than 8.5mph with significant time stopped (as happens in group rides). In my local loop that I ride all the time my best speed was an average of 7mph, normally 6.5 when I go by myself with no stopping. It has less total climbing than these other loops, but the flat sections require much more power just to pedal along in 32-32 or 32-28 gears.


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## eurorider (Feb 15, 2004)

I would agree with Chester and nino here...I have a question though .. is it safe to say that if you had two identical bikes, except one is FS while the other is a HT (eg. RM Vertex and Element), that they shouldn't necessarily run the same tire pressures? On a rather rough course, wouldn't you say that the HT should run slightly lower pressure particularly in the rear compared to the FS?

This probably relates to what barrows is saying ....at equal tire pressures, on a rough course, the FS will get jolted and thrown around less ...thus preserving forward motion?


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## barrows (Jul 6, 2004)

*Most People I know...*



Chester said:


> Lets see, most people I know ride about .001 of the time in #1 meadows and try to avoid #2 gravel 99% of the time, and only ride #3 tarmac getting to and from the trail. But they will use these tests to allow their thinking about tires to go along with what makes them comfortable rather than what makes them fast.
> They like softer, wider, more comfortable tires and will use this study to back up their prior conclusions.
> I'm guessing that about 90% of them would do faster times on your 39 psi Nokians, but they will now use "meadow" and "gravel" tests to show they should use Roll-X Pros at 30 psi......even though they may go from March to October without ever pedaling through even one soft green meadow.
> Don't the Germans still have plain old "dirt" in some sections of the country?


I was just trying to point out why lower pressures can be more efficient. Everyone will have to find a balance for their terrain/courses to see what works best. Back when I raced a full season of xc races, everyone rode hardtails, with 1.9" tires, with 50 psi in back and 45 psi in front. Now on my terrain and courses, I now know that I am faster with a slightly wider tire at lower pressure-around 36 psi rear and 34 front. I am not talking about super heavy 2.4" tires here, just light 2.1-2.2s, like Racing Ralphs. I would love to try NBX lite 2.2s as well. Yes, one has to look honestly at their terrain: for instance this summer I will be doing a 50 mile race, the course is awesome but here is the dilemma: the first few miles climb up a paved road, and you ride this section twice-this section is also one of the best places to gain positions. The rest of the course is moderately technical single and double track-but it is quite rough with some very rocky and rooty sections, so figuring out the pressure to run is tricky, too low and you are bogging on the road section, but too high and you are losing it everywhere else. I am thinking a narrower tire in the back, where most of the RR would come from due to weight transfer while climbing, and a little wider tire in the front for control and security descending.


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## Chester (Jan 15, 2004)

*Does significant motion redirection even occur?*



eurorider said:


> I would agree with Chester and nino here...I have a question though .. is it safe to say that if you had two identical bikes, except one is FS while the other is a HT (eg. RM Vertex and Element), that they shouldn't necessarily run the same tire pressures? On a rather rough course, wouldn't you say that the HT should run slightly lower pressure particularly in the rear compared to the FS?
> 
> This probably relates to what barrows is saying ....at equal tire pressures, on a rough course, the FS will get jolted and thrown around less ...thus preserving forward motion?


"thus preserving forward motion"....or as Barrows put it "When the tire is hard and narrow, with little volume, everytime it hits an embedded rock it rises up to roll over the rock, when it rises up, forward momentum is converted to upward momentum, and to maintain the same speed, more force must be applied."

Sounds reasonable.....sounds like commons sense.....however I would like to see anyone show me some scientific formula or test results to quantify it....
Is it a micro amount of momentum lost or is it significant, such that one should make a large change in tire pressure for reasons aside from comfort and control.

You have to be very careful in taking up theories that sound like common sense.
We always see endless over-estimations of the value or harm done by rotational weight verses frame weight.... Most riders are walking around with a wildly over estimated sense of the value of dropping rotating weight versus just plain weight. But these theories just continue to be taken as fact, and certainly wheel makers are only too happy to agree with the "common sense".

I would say that the biggest problem I have experienced with higher psi tires bouncing is not loss of forward momentum from the redirection of energy, but rather loss of uninterrupted traction and overall loss of cadence or rhythm. Even in that, I am not certain about the scientific validity, but it does seem to interfere with my smooth flow if I am really into an all out timed event or climb.


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## eurorider (Feb 15, 2004)

Chester said:


> I would say that the biggest problem I have experienced with higher psi tires bouncing is not loss of forward momentum from the redirection of energy, but rather loss of uninterrupted traction and overall loss of cadence or rhythm. Even in that, I am not certain about the scientific validity, but it does seem to interfere with my smooth flow if I am really into an all out timed event or climb.


I agree.

Also, a higher psi is obviously less comfortable and discomfort (ie. in the hands, arms, shoulders, back, etc.) could be energy wasteful as well. However, I imagine with considerable training, the body becomes more efficient and less susceptible to this problem. And there has to be a certain amount of discomfort when you are racing, especially for a less than 2 hour XC race.

I remember the very first race I ever did ...25lb hardtail and trying to get some kind of advantage, I ran a rough, technical course at 70psi ...my body was hurting for a couple of days.


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## TeXe (Apr 6, 2004)

Chester said:


> "thus preserving forward motion"....or as Barrows put it "When the tire is hard and narrow, with little volume, everytime it hits an embedded rock it rises up to roll over the rock, when it rises up, forward momentum is converted to upward momentum, and to maintain the same speed, more force must be applied."
> 
> Sounds reasonable.....sounds like commons sense.....however I would like to see anyone show me some scientific formula or test results to quantify it....
> Is it a micro amount of momentum lost or is it significant, such that one should make a large change in tire pressure for reasons aside from comfort and control.


I suggest you do some testing on this subject. Take a gentle downhill littered with rocks and/or roots and a buddy to ride with you. Yoyr buddy keeps his bike settings the same trough out the hole test and you change tire pressures (and maybe even tires). Roll the hill side by side or sequentially and compeare the gab between you increasing and decreasing while you change your tire settings. Not very scientifical but you can see the differences with your own eyes. Sometimes on group rides it's funny to notice when compearing yourself to some old timer xc guys with their rock hard tires, that when the terrain gets rough their bikes simply don't roll, they just rattle and lose speed. They do fine on tarmac though! Earlier you also said that there is no trail that constantly has 1" rocks. Well, I say you haven't ridden on rocky terrain, and the rocks are a lot bigger than 1"! But if you really never ride on rough terrain just don't bother with the testing. Keep your skinnies pumbed up to 50psi.

But what is fastest setup for given course is really another story. Courses vary a lot and the clock is the only correct device to define the best tires.


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## Chester (Jan 15, 2004)

*You are looking at the exceptions to typical cross country race courses*



TeXe said:


> I suggest you do some testing on this subject. Take a gentle downhill littered with rocks and/or roots and a buddy to ride with you. Yoyr buddy keeps his bike settings the same trough out the hole test and you change tire pressures (and maybe even tires). Roll the hill side by side or sequentially and compeare the gab between you increasing and decreasing while you change your tire settings. Not very scientifical but you can see the differences with your own eyes. Sometimes on group rides it's funny to notice when compearing yourself to some old timer xc guys with their rock hard tires, that when the terrain gets rough their bikes simply don't roll, they just rattle and lose speed. They do fine on tarmac though! Earlier you also said that there is no trail that constantly has 1" rocks. Well, I say you haven't ridden on rocky terrain, and the rocks are a lot bigger than 1"! But if you really never ride on rough terrain just don't bother with the testing. Keep your skinnies pumbed up to 50psi.
> 
> But what is fastest setup for given course is really another story. Courses vary a lot and the clock is the only correct device to define the best tires.


1. "Take a gentle downhill littered with rocks and/or roots and a buddy to ride with you. "

First of all, I don't doubt you can go faster on a rough downhill section with lower tire pressure. But down hill testing of rolling resistance is the least meaningful of all. After all the need to apply more power is least likely to be involved in downhill sections where you are more likely to use brakes to slow a bit rather than pedals to apply more power.
We are talking mostly about "loss of power" related to rolling resistance rather than control issues.

2. "Earlier you also said that there is no trail that constantly has 1" rocks. Well, I say you haven't ridden on rocky terrain, and the rocks are a lot bigger than 1"! "

Constantly.......please keep in mind that the word constantly means all along the rolling path of the trail. Meaning as your wheel turns, it is hitting 3 or 4 one inch or greater protruding rocks with every rotation.....and you are not missing/avoiding any of them.
I don't doubt you sometimes ride on trails with lots of 1 inch, 3 inch and and greater rocks protruding out, but when you take a realistic count of those that you hit and divide them into the distance of an entire cross country loop you will find that they are spread well out and that while the impact is uncomfortable it is not slowing your momentum such that basing your entire tire selection on them is efficient.
Now, you may come back and say that you ride trails that are nothing but protruding rocks 75% of the time.....with not even one tire rotation between them.......and I don't doubt you're telling me the truth.......
Its just that there is seldom ever a official cross country race run on such courses.
Instead, most cross country courses have large areas of rather smooth track interspersed by small difficult or rock filled sections. In fact that biggest complaint from many racers is that the courses are not technical enough.

So fine, for your rides with your buddies through rock gardens, downhills etc.......use whatever tires you find comfortable, just don't make believe that those tires are going to be most efficient on most cross country race courses. And I'm not saying you have to pump tires up to 50 psi...........but I think Nino is closer to the mark when he puts his Nokians at about 39 psi with a very fast tire.


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## ccm (Jan 14, 2004)

Chester said:


> 1. "Its just that there is seldom ever a official cross country race run on such courses.
> Instead, most cross country courses have large areas of rather smooth track interspersed by small difficult or rock filled sections. In fact that biggest complaint from many racers is that the courses are not technical enough.
> .


In BC we don't have Euro autobahn XC courses.
The upcoming North Shore Marathon and especially last years Enduro will feature (have featured) ~90% rough trail - for every wheel revolution you would encounter at least 1 (usually may more) square-ish edged bumps greater than 1cm high, and about 30% of the time many square-ish edge bumps greater than 2 cm high (even if you try to steer around the worst of it). As well smoother sections are often soft. The XC races where I have podiumed, I have made my gains on the downhill and corners, and I just wheel suck (draft) on the road sections. 
But maybe I should just shut up, since I don't want everyone to have the same technical advantage I have enjoyed.

One problem with low pressure and Stan's, I have a couple of times pulled enough lateral G's on smooth but grippy corners to pull the bead off the rim and lose air. I agree with Nino than extreme low pressure can be bad. So if you need more vertical compliance use dual suspension or bigger tires.


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## Ultra Magnus (Jan 13, 2004)

Many of us don't ride on groomed XC "courses". We just ride out on natural terrain, and here in the desert, most is rocks. 

ccm- it's funny you mention that smoother sections are usually soft. I run into that all the time, especially on a new trail I'm not familiar with. On many climbs you have two choices, the smooth line or the rough line, with many 1" rocks, like I'd have to imagine 50 per revolution of the tire (imagine rock landscaping in someone's yard, but all the rocks are embedded into the ground so they don't move under you tire). The smooth line is deceptive because often it is soft or loose, causing a loss of traction.


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## jaydogster (Feb 12, 2005)

It seems in this debate of high volume vs low volume, there's much more at stake than simply air volume and footprint.

Its a balance of flat risk vs comfort vs efficiency vs handling characteristics. Anyone who's latex'd a Python Airlite will attest to the fact that the thinner casing won't allow them to run the same air pressure that they in the UST version without risk of a puncture. Same tire tread/volume - but you've traded less weight for increased air pressure. What gamble are you willing to take when it comes to the risk of flatting? How much time is the loss of confidence worth to you (in high speed handling)?

At high speeds, on hardpack with small undulations, a high volume tire at low pressure will bend and drift on the rim - dangerous and difficult to predict. A narrow tire at medium pressure would roll fast but is prone to flatting at the high speeds, especially if the side walls are thin. So common sense would say a high volume tire with "medium" pressure and a fast rolling tread would be the logical choice in this situation. It goes without saying that the tread pattern should suit your riding style - predictable braking, cornering, etc...b/c at high speeds (what we're shooting for here) the minor varriances in handling make more of a difference than weight or footprint. Flatting or laying in the dirt will cost you the most time of all! And we're not even taking into account HT vs FS in this equation - it can swing the direction of choice - IMO, a FS allows for lighter tires with slightly lower pressure, but its all course dependent. Too soft and bike will "wallow". Too hard and it will "skate"...and the dog chases its tail.....


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## barrows (Jul 6, 2004)

*Agree...*



jaydogster said:


> It seems in this debate of high volume vs low volume, there's much more at stake than simply air volume and footprint.
> 
> Its a balance of flat risk vs comfort vs efficiency vs handling characteristics. Anyone who's latex'd a Python Airlite will attest to the fact that the thinner casing won't allow them to run the same air pressure that they in the UST version without risk of a puncture. Same tire tread/volume - but you've traded less weight for increased air pressure. What gamble are you willing to take when it comes to the risk of flatting? How much time is the loss of confidence worth to you (in high speed handling)?
> 
> At high speeds, on hardpack with small undulations, a high volume tire at low pressure will bend and drift on the rim - dangerous and difficult to predict. A narrow tire at medium pressure would roll fast but is prone to flatting at the high speeds, especially if the side walls are thin. So common sense would say a high volume tire with "medium" pressure and a fast rolling tread would be the logical choice in this situation. It goes without saying that the tread pattern should suit your riding style - predictable braking, cornering, etc...b/c at high speeds (what we're shooting for here) the minor varriances in handling make more of a difference than weight or footprint. Flatting or laying in the dirt will cost you the most time of all! And we're not even taking into account HT vs FS in this equation - it can swing the direction of choice - IMO, a FS allows for lighter tires with slightly lower pressure, but its all course dependent. Too soft and bike will "wallow". Too hard and it will "skate"...and the dog chases its tail.....


Jay I agree, and I certainly am not saying everyone everywhere should run extremely low pressures. You have to experiment with a given tire/tube/sealant/rim combo. I usually start with 40 psi, and lower the pressure in 2-3 pound increments to find the point at which the tire no longer handles well, where it starts to wallow around on the rim and lose precision. Then I know where the lower pressure limit is for that tire, and can adjust upwards to suit the given conditions. I must say for 2 seasons now I have had very good rersults running stans in standard tires (kendas, karma and blue groove lites and combos) I have not had any sidewall failures, and have never had to put in a tube, I have had 2 punctures bad enough to need a shot of air from my CO2, but then they sealed up and I was on my way-Pressures between 32-38 psi. Of course this is for my terrain and may not work as well for someone else's.

Considering terrain, I am glad to hear some people weighing in on the idea that their riding terrain does feature long rough sections where lower pressures are an advantage. Another consideration is this: I have been on many courses where one is climbing a doubletrack section of old (no longer used by vehicles) jeep track. Typically these sections will feature one somewhat smooth line, bordered by rough sections. If you are in a line of riders climbing on this terrain passing can be very difficult because you must leave the smooth line and then accelerate in the rough to pass-if you are running a little lower pressure you have a greater choice of lines available and more passing chances.


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## jcw (Dec 31, 2003)

No offense Nino, as I know you're very knowledgable, but I think Leonnard knows what he's talking about. I've heard this same claim (better performance at lower psi) from many industry sources . Here is the relavent copy from the link (response from Josh at Zipp) from Leonnard's article :

The other issue to consider is that most every tire on the market runs at optimal rolling resistance between 105 and 125psi depending on load and road surface condition. We have seen data from numerous manufacturers and had enlightening talks with others to learn that nylon cased tires like Michelin or Continental tend to run optimally around 105-115 and cotton or bias cased tires like Vittoria or Vredestein tend to run optimally at 115-125 maybe as high as 130 for Vredestein, but all of them actually will increase in rr at higher pressures due to the tread rubber beginning to fail in shear as it locally deforms to meet the contour of the road imperfections when the casing is too rigid. Think of it in terms of heat input, as the overinflated tire struggles to conform to all the tiny surface imperfections to make the necessary contact patch, a lot of heat is generated. Not only is there higher rr, but faster tire wear as well at higher pressures, not to mention the tires decreasing ability to stay mounted on the rim as pressure increases. In an ideal world tire manufacturers would list a recommended pressure and not just a MAX pressure (the max pressure is simply a predetermined percentage of the bursting pressure of a given tire as set out by industry standards and has nothing to do with the pressure you should actually run) but they are between the rock and hard place as consumers continually push for higher and higher pressures feeling that 'if some is good, more is better'. Of course none of this even mentions comfort, which we believe to be of increasing importance as more and more data has shown fatigue to be caused by vibration. It may be that by increasing tire pressure by 20-25 psi, you feel faster as your tires are transfering more of the high frequency vibration to your body (you're feeling a higher frequency 'faster' vibrations' so it really does 'feel' faster) but are actually expending more energy to do it, while simultaneously wearing out the tires faster and inducing fatigue.

Looking to pro road teams, most of them are running 100-110 psi in tubulars and 105-120 psi in clinchers, and this has been a bit of a knock against the clinchers from the pros, that they prefer the lower pressures for improved handling, grip and feel, but need additional air to prevent pinch flats. Especially of issue are rainy races, where they may even lower pressure to 95 psi or so for better grip and control in the corners. The only real exception here would be track racing, especially on wood, where the surface is so smooth that very high tire pressures can yield excellent RR results, but still generally reduce grip slightly, but even this is specific as a board track may runn well at 220psi, but a concrete track favors 150-160psi, and some track surfaces are no better than most roads... For an analogous example, look to Inline Skate racing, where they carefully select the durometer (firmness) of their wheels to the surface they are racing on, this is nearly as critical as ski wax in ski racing as it can win or lose races for you. It is so critical as too hard a wheel will get you dropped like a hot rock on most road surfaces, whereas that same wheel is the only way to be competitive indoors on wood.
Josh

\


nino said:


> well- i'd say Lennard should go back to the drawing board!
> no one is using road tires at 100 psi excepty maybe at the classic races that go over cobblestones where the pros use extra-wide tires to fight pinchflats and get some comfort.
> ALL test, including the one i posted initially, show a DECREASE with HIGHER PRESSURE on tarmac. and on a roadbike you definitely can feel those couple of watts that are lost as the speeds you reach are more constant. it's pretty easy to tell the differences on a roadbike.
> 
> ...


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## nino (Jan 13, 2004)

*hmm...*



jcw said:


> No offense Nino, as I know you're very knowledgable, but I think Leonnard knows what he's talking about. I've heard this same claim (better performance at lower psi) from many industry sources . Here is the relavent copy from the link (response from Josh at Zipp) from Leonnard's article :
> 
> \


it all depends on the tire
what's oit made of
tubular or clincher
width?

if you have a look at the scanned test of those tubular tires you can clearly see that the numbers with the higher pressure setting (8.5 bar / 123 psi) make for lower RR. i don't believe pro teams are giving away precious watts when they do a time trial.

we are not talking about grip and comfort here! in pure RR higher pressure means lower RR but at a certain amount the gains are very little but comfort and grip go down big time. i just don't agree that 95 psi are used. at least not on good streets. and remember, they always use 23mm tires. a 20mm tire needs more pressure from the start.


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## jcw (Dec 31, 2003)

*more to do with road surface...*

my understanding, limited as it is, is that it's much more dependant on the roughness of the road/track surface. Of course all tires are not created equal, and there will always be some that are faster than others for a variety of reasons. But as I see it, the real question here is not whether tire A is faster than tire B, but under what conditions is tire A the fastest (when compared to itself). The test you referred to was conducted on a wooden track, which for most of us is not real world conditions. That test wil only tell you which is the fastest tire/pressure for riding on that specific wooden track. You can not take those numbers and extrapolate to all riding conditions. Josh addresses this in his letter. And I'm sure the pros ride optimal pressure for whatever surface their riding on - I have no first hand experience with this, and can only repeat what I've been told by others who do.



nino said:


> it all depends on the tire
> what's oit made of
> tubular or clincher
> width?
> ...


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## Moo Shoo Pork (Jan 17, 2004)

*Nino, Awesome Post*

Nino,

I always like your posts because you point out comparisons that try to maintain study integrity. I'm not trying to steal the thread, but are you in Europe? Have you seen/talked to anyone riding the new 2.3 Python Airlights? For my style of riding the Pythons pretty much do the trick at about 35/30 back/front psi. But, I would love to get hold of the 2.3 Pythons. IMO, the Pythons are some of the best for hardpack . But w/ 2.3 up front, I'll be able to really corner. Anyway, thanks for all of your posts!


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## nino (Jan 13, 2004)

*I'm from Switzerland*



Moo Shoo Pork said:


> Nino,
> 
> I always like your posts because you point out comparisons that try to maintain study integrity. I'm not trying to steal the thread, but are you in Europe? Have you seen/talked to anyone riding the new 2.3 Python Airlights? For my style of riding the Pythons pretty much do the trick at about 35/30 back/front psi. But, I would love to get hold of the 2.3 Pythons. IMO, the Pythons are some of the best for hardpack . But w/ 2.3 up front, I'll be able to really corner. Anyway, thanks for all of your posts!


i'm right in the middle of Europe: Switzerland.
i don't like the Python as those don't do good when trails get humid/wet. and 2.3" is definitely too big for my taste. how heavy is that tire? still the same thread than the 2.1"?

i have a bad memory with pythons:
in 2001 my brandnew S-Works HT had crossmax tires and Python UST tires. never had i ridden a bike which felts so slow as with those Pythons !! when i changed the wheels/tires the bike became alive. no wait, i rode a slower bike last year. i spend 2 weeks in Mexico and once rent a beach old beat up beachcruiser which seemed to have some glue on the tires. i hardly couldn't bring it up to speed...


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## Moo Shoo Pork (Jan 17, 2004)

*Beach Cruzin*

i have a bad memory with pythons:
in 2001 my brandnew S-Works HT had crossmax tires and Python UST tires. never had i ridden a bike which felts so slow as with those Pythons !! when i changed the wheels/tires the bike became alive. no wait, i rode a slower bike last year. i spend 2 weeks in Mexico and once rent a beach old beat up beachcruiser which seemed to have some glue on the tires. i hardly couldn't bring it up to speed...[/QUOTE]

LOL,

The view from a 40 lb beach cruiser doesn't sound bad at all  For wet trails, you are definitely are correct. The Pythons would not be the first choice. But, since it is sunny 90% of the year hear in Southern California. I don't really have to deal with that issue. I run Stan's in both my FS and HT.

The new 2.3 pythons are suppose to only weight 645 gm. That is light for a true 2.3. And, I would run it up front for more downhill and cornering stability and control. I heard that Europe already has them.


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## MikeDee (Nov 17, 2004)

nino said:


> in german "MountainBike" they have that all scientific test about rollingresistance. a guy got his diploma on this topic. they measured all sorts of things about rollingresistance and finally we have some scientific numbers and proofs about bike-tires! rollingresistance eats up to 50% of our power so maybe this is a really important topic, right?


Does this magazine have a website? What's the URL?


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## nino (Jan 13, 2004)

*web...*



MikeDee said:


> Does this magazine have a website? What's the URL?


http://mountainbike-magazin.de/


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## bonkey (Mar 10, 2004)

*oops*

nothing....


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## bonkey (Mar 10, 2004)

*Minion 3.0s here I come!*

So why are my Maxxis Minion 2.7s so dang 40a, SLOW-reezay? Sure I'd rather ride it downhill and through rocky sections and even on really steep fireroads (wattage at the pedals? Goose-egg!), but I garauntee pedaling that tire up hill (in a meadow or up and over big rocks) has got more rolling resistance than those 2.3 NBX's you guys keep talking about.

Seems like if it were scientific there would be more variable isolation. For example instead of using 3 different tires with 3 different tread patterns and 3 different compounds, they would pick say, a WTB Motoraptor in a 1.9, 2.14, and a 2.4. Then you could compare them to a WTB Mutanoraptor of the same size and compound (then you might get something worth evaluating). Even then, the individual tires are going to ride better at different psi, so then you gotta run them over and over again to find out what the optimum psi is for every tire. Statistically, this test is a quagmire of illegitimacy, and deviant extrapolations. Even conclusions made on trends of this test are all inconclusive, at best. I realize that the results made sense, but you gotta understand the charts are explaining a lot of variables.

I don't race too often, but I do mechanic for quite a few racers. We always walk the course before, and pick the tires/psi that we think will run best on the course. After a day of walking and practice, we're usually right on. And sometimes it's a fat slick and sometimes it's a skinny knobby, and sometimes it's something in between. I don't think this subject is so easily solved by rules of thumb.

Seems to me that it is just more writers trying to be scientific, but as it turns out, it's just writers indoctrinating gullible people into the idea of being really obstinate and smart about nothing. Then again, I'd write a bunch of technical mumbo-jumbo for a chance to get a free set of SMT cranks in the name of science.  . If I own a set of them and publish my workouts, does that make me scientific?

In the words of Napoleon:

Heck Yeah it does! I already told you I was doing scientific analysis of rolling resistance on Pedro's sledghammer all summer long! Gosh! What would you do with cranks like that?

Bonk


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## Boj (Jan 13, 2004)

bonkey said:


> I don't race too often, but I do mechanic for quite a few racers. We always walk the course before, and pick the tires/psi that we think will run best on the course. After a day of walking and practice, we're usually right on. And sometimes it's a fat slick and sometimes it's a skinny knobby, and sometimes it's something in between. I don't think this subject is so easily solved by rules of thumb.


What scientific methods do you employ in determining optimum tire/psi?


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## nino (Jan 13, 2004)

Boj said:


> What scientific methods do you employ in determining optimum tire/psi?


most "sophisticated" is...

TIME! 
all you need is a stopwatch.
i did it - got the results - end of the story.


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## bonkey (Mar 10, 2004)

We don't really use science per se. Usually, we're trying to find that happy balance between speed and comfort. Stronger riders need little comfort and outta shape riders need more comfort, so we pick tires according to the rider and terrain. Get'm as fast as they can be without making their bodies so tired they bonk. Typically, we have between 20 tire models at hand (maxxis, wtb, kenda, and couple of ircs... why we picked those is a whole 'nother story), and just walking the course we eliminate 1/2 of them right off the bat. 

I normally talk to my riders while we figure out lines and generally what they are thinking. In the first lap of riding we'll carry three sets of tires and swap in and out tires. PSI all depends on the tire and the rider. Weather will play a big factor too, so we remember what we did last year, but it may have no effect on our choice this year.

Just as an example my fastest rider generally uses the same 3 tires for the same weather, reguardless of terrain. If the terrain is dry, he normally uses the Maxxis Wormdrive TS. Over rocky terrain he'll run as low a 15 psi and when we head up north he runs 30 psi in the front tire. He likes that tire because it is basically a slick with heavy side knobs, he likes the maxxis because they have really stiff sidewalls, so they run really well at 15psi (front tire). Usually he's trying to decide between the Wormdrive 1.9, Ranchero 2.1, or Highroller 1.9 or 2.1.

My slowest rider on the same course will do WTB mutanoraptors 2.4, because he can't ride up the obstacles without higher volume tires. He'll run right around 30 psi in the front, because the thinner side wall doesn't handle so well in the corners.

All that being said, different riders will need different tires at different psi's to ride their most effective race. In the end I think tire choice has more to do with the ability of the rider and how he/she rides the terrain, than the rolling resistance of the tire over the terrain.


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## jcw (Dec 31, 2003)

*Wow, great post...*

Great post Bonk. The big picture, what a concept.



bonkey said:


> All that being said, different riders will need different tires at different psi's to ride their most effective race. In the end I think tire choice has more to do with the ability of the rider and how he/she rides the terrain, than the rolling resistance of the tire over the terrain.


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## Boj (Jan 13, 2004)

bonkey said:


> So why are my Maxxis Minion 2.7s so dang 40a, SLOW-reezay? Sure I'd rather ride it downhill and through rocky sections and even on really steep fireroads (wattage at the pedals? Goose-egg!), but I garauntee pedaling that tire up hill (in a meadow or up and over big rocks) has got more rolling resistance than those 2.3 NBX's you guys keep talking about.
> 
> Seems like if it were scientific there would be more variable isolation. For example instead of using 3 different tires with 3 different tread patterns and 3 different compounds, they would pick say, a WTB Motoraptor in a 1.9, 2.14, and a 2.4. Then you could compare them to a WTB Mutanoraptor of the same size and compound (then you might get something worth evaluating). Even then, the individual tires are going to ride better at different psi, so then you gotta run them over and over again to find out what the optimum psi is for every tire. Statistically, this test is a quagmire of illegitimacy, and deviant extrapolations. Even conclusions made on trends of this test are all inconclusive, at best. I realize that the results made sense, but you gotta understand the charts are explaining a lot of variables.


Rolling resistance is not purely a function of size but tread pattern tire construction etc and also many of the rolling resistance functions vary according to terrain. Additionally different riders will weight different, put out different power and have differing sensitivity to bumps, control over the bike etc. If you refer to second graph you'll find they did run the test on the same tires of differing width, scroll a little bit down they did the PSI test as well albeit on only one tire.



bonkey said:


> We don't really use science per se. Usually, we're trying to find that happy balance between speed and comfort. Stronger riders need little comfort and outta shape riders need more comfort, so we pick tires according to the rider and terrain. Get'm as fast as they can be without making their bodies so tired they bonk. Typically, we have between 20 tire models at hand (maxxis, wtb, kenda, and couple of ircs... why we picked those is a whole 'nother story), and just walking the course we eliminate 1/2 of them right off the bat.
> 
> I normally talk to my riders while we figure out lines and generally what they are thinking. In the first lap of riding we'll carry three sets of tires and swap in and out tires. PSI all depends on the tire and the rider. Weather will play a big factor too, so we remember what we did last year, but it may have no effect on our choice this year.


So you find yourself fit enough to criticize an actual scientific test based on lacking variable isolation yet when you are selecting optimum (fastest) tire for your riders (exactly the same objective as the German tests) you don't use science *at all*?

It's simple enough to measure speed but I'm assuming your riders bikes are decked out with powertap or SRM cranks to measure power they're putting out around the course? If not that's very poor variable isolation. Additionally you say it's a balance between speed and comfort. Again, how do you measure comfort? Good old, assomometer? If so, how do you account for rider bias? I'm assuming you take your riders out and perform double blind tests to determine without bias which tire is most comfortable. In case you don't have any power measuring devices this would be mandatory if your test is to be considered valid.

If you compare the German test to your own which one would you say has more scientific merit? Which one would an engineer or a scientists?

The purpose of German tests was not to determine be all and end all setup for racing or to draw definitive set of conclusions on what is the fastest set up. It was simply to uncover how rolling resistance changes with respect to certain variables on certain terrain. You're welcome to criticize them if you think it will give you cred around forums, but you'd be a fool if you didn't save a copy of them for yourself considering what you do.


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## 20.100 FR (Jan 13, 2004)

My contact at a French tires producers said about the previous test :

"what is the clue of testing rolling resistance of mtb tires on a sleek hard metal surface ? This is only revelant for road tires"

So i think that this test try to adress this issue and is interesting for this.

Even if it is not perfect, i think it's a steep in the good direction. Science can do good in improving our riding experience


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## pintense (Jan 14, 2004)

*Nino, what wheelset do you use*

Hi,
I'm from Portugal and my weight is 69 Kg.I would like to ask you about your wheelset.
I have XMAX SL disc im my Spider and XL disc in my Tracer. I use UST tires (Conti Twister, all Hutchs, Larsen's, Red Phoenix from Tioga and Serac's from IRC).
I have about 1.5 years experience with Stan's in UST rims/ non UST tires. Bad experience with Big Jim Schwalbe (explode in my hands). Good experience with Conti Survival 2.3 and Explorer's. Twister Supersonic's and Stan's ....45 psi or the bead will go out from the rim (happened to me in a marathon race).
Finally...what is your wheelset? Eclipse works fine? What the weight of the Eclipse system?
I have a decision to make : to buy or not to buy a non UST Wheelset (the new ones from ExtraLite at 1320 g pair for disc !) and mount either a UST tire or a non UST tire. I have no experience with this combos (non UST rims with non UST tires but "tublessed" or non UST rims with UST tires).
What your opinion?

Thanks in advance.

paulo from portugal


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## 20.100 FR (Jan 13, 2004)

Paulo :
You should make a dedicaded thread with your questions.


Nino : i've been talking a lot about this essay with friends.

Could you tell me if they used statistics ?
How many times did they did each mesurement ?
How did they take into account the 5% error of the srm sensor ?

Thanks.
V


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## nino (Jan 13, 2004)

*hmmm....*



20.100 FR said:


> Nino : i've been talking a lot about this essay with friends.
> 
> Could you tell me if they used statistics ?
> How many times did they did each mesurement ?
> ...


they did over 350 different runs...that's pretty much and should do a statistic.

they say error of the SRM cranks is 0.5% only!! it's the pro-version of these cranks.


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## bonkey (Mar 10, 2004)

Boj said:


> If you compare the German test to your own which one would you say has more scientific merit? Which one would an engineer or a scientists?


Sure, the Germans definitely got me on science. No doubt about that. I prolly won't save this one to my desktop, I'm no good with German, but if you change everything to a language I can read, I would save it for sure.

Perhaps I should have put a big IMHO at the beginning of my post. I never said my method was better than the article...I was asked how I determine psi, and thought it deserved more than a sentence or two.

And I clearly stated that *my methods were not scientific*. Whether or not I use science is irrelevant in my criticism of the article. IMHO I think the article could have been better.

My science days of college are behind me now. I take a personal approach to mountainbike racing. I'm not about winning. My concern is the rider. His psyche, how comfortable she is, how pushed he feels, how her legs burn, how happy he is before, during, and after the race. And if swapping tires makes my racer happy, then I'll do it. Happy riders ride better. And hardworking, talented, happy riders ride the best. That's my _gnosis_. Provide every opportunity for racers to be happy, and they will never do you wrong. I've yet to see a grouch standing on the podium.

Here's some science of comfort: Comfort is a function of the time it takes to do a lap and the size of your smile at the end of the lap. We only use the assometer when we need to find the 'area under the curve'. The drawback to this method is that it uses up my inventory of latex gloves and velo grease. LOL! Crap! I'm laughing at myself again... 

You hit the nail on the head: *rider bias*. That's something that science will always have a hard time accounting for, and precisely the center of why I do the things the way I choose to. Treating the rider as the independent variable, not the tire or the bike. It's a backward way of looking at it, and precisely why my best riders don't leave for bigger teams.

I'm sure someday science will tell us what tire and psi to use in every situation, but until that day, I will still be waiting in the wings.

Bonk

p.s.
Oh, thanks for damaging my street cred!


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## nino (Jan 13, 2004)

*smile....*



bonkey said:


> Sure, the Germans definitely got me on science. No doubt about that. I prolly won't save this one to my desktop, I'm no good with German, but if you change everything to a language I can read, I would save it for sure.
> 
> Perhaps I should have put a big IMHO at the beginning of my post. I never said my method was better than the article...I was asked how I determine psi, and thought it deserved more than a sentence or two.
> 
> ...


i completely understand what you are trying to say BUT

better results make for even bigger smiles...that's where your error is. it's the results that make for smiles not the assometer!

imagine your riders would have the "fastest" tires and equipment instead of the most comfortable one...in sport anything that counts is beeing faster/better and if you get better results because of different equipment that will sure make for a big smile on those sportsmans faces. if they feel comfortbale or not... they will feel right at home if that is what is needed to do good.

for me that's pretty simple "science"


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## bonkey (Mar 10, 2004)

*dagreed.*

Nino,

I agree with you to a point. The "fastest" tire isn't necessarily the best tire choice. A more comfortable tire will preserve rider energy, and keep a rider from exhausting himself. I agree that wins put smiles on faces, but so do personal records, personal bests, and finding that perfect balance between ability and challenge.

So in my second post on how I choose psi, a poorer rider will not be able to pedal the same tire as a talented fit rider, simply on the notion that a faster tire is more challenging and takes more ability to ride. This of course is all FLOW theory, so to illustrate...

Sure a poorer skilled rider can ride that faster tire, but he may feel anxiety, which I would consider as power not put to the pedal. So a faster tire will fatigue the rider faster and rider rides slower. The faster tire ending up not really being faster, but a hindrance to a rider's lap time.

On the other hand a highly skilled rider on the fatter 2.4 would not experience a good ride, because the larger tire decreases the ability a rider needs to complete the lap. He has power to use, but perhaps not a way to exploit it. At the end of the race, his comfort level is such that he could ride all day and not feel tired, but not in a way that he maximizes the wattage he could output in 5 laps. Or in terms of this wattage being used moving more weight, versus generating more speed.

This is why in my original post I made mention of Maxxis 2.7s. Simply overkill, even pedalling up a meadow.

There you have it: the balance between comfort and anxiety. Maximize the rider by tailoring the bike to the rider. The whole thing being rider-centric. It isn't the concept that somewhere out there is a ethereal bike perfect for everyone (and I'm not saying that that's what you're saying). The concepts come from two different directions. Is one right and the other wrong? No. Just two different ways of attacking the problem... beating time.

One thing we know for sure about this study: That rider (or few riders) rides on asphalt, gravel, and meadows most efficiently with particular tires.

I really would've like to have seen not just a bunch of test rides, but a bunch of test riders. Then it would be a statistical inference to: "populations ride better with tires on terrain". That way we have an assessment of many riders with many abilities, and therefore could infer trends for everybody, instead of a singular riding group. This is the crux of my problem with this study. If anyone out there can findout how many rider samples there were and the number is a sample size worthy of science. I'll admit to my fault, and pray penance to the mtbr gods.


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## nino (Jan 13, 2004)

*agree BUT...*



bonkey said:


> Nino,
> 
> I agree with you to a point. The "fastest" tire isn't necessarily the best tire choice. A more comfortable tire will preserve rider energy, and keep a rider from exhausting himself. I agree that wins put smiles on faces, but so do personal records, personal bests, and finding that perfect balance between ability and challenge.
> 
> ...


i agree but all they were doing is measuring Rollingresistance. no more and no less. as i already stated in my original post i think this is good to know but in the real world RR isn't isolated and we need to take into account many,many other factors too.

but as the measuring tool of all time truth TIME is the best way to measure if a tire is fast or not. TIME includes just everything wheter it be ability, different terrain or weather etcetc...if it's faster it's faster and that's what it's all about.

so to make and end:
i found THE perfect tire in the Nokian NBX Lite. no, it's not 2.4", no, i don't have it as low as 1.5 bar, it doesn't last an eternity, it isn't the lightest ....but i do the fastest laps with it. that's what makes a smile on my face


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## ccm (Jan 14, 2004)

nino said:


> but as the measuring tool of all time truth TIME is the best way to measure if a tire is fast or not. TIME includes just everything wheter it be ability, different terrain or weather etcetc...if it's faster it's faster and that's what it's all about.


Nino your scientific method does not eliminate placebo effect.

Maybe you liked the look and light weight of those Nokian's and it inspired you to "prove" that they were faster on your test ride.
I get far more variability during my interval training or even for races (that I repeat often) due to personal factors than due to equipment
Anyway I think that the point of that essay is valid, that wider tires and lower pressure (too a point) can be faster on mountian bike terrain, than what the scientific testing on steel treadmills indicates.
Race car drivers spend endless amounts of time trying to figure out tire pressures, rubber compound, suspenion set up and so on, with much data logging and scientific instrumentation, and it still comes down to a black art, not a science to achieve faster lap times.


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## nino (Jan 13, 2004)

*no placebo...*



ccm said:


> Nino your scientific method does not eliminate placebo effect.
> 
> Maybe you liked the look and light weight of those Nokian's and it inspired you to "prove" that they were faster on your test ride.
> I get far more variability during my interval training or even for races (that I repeat often) due to personal factors than due to equipment
> ...


could well be what you say BUT i ride my trails for 15 years and know them in and out. as i already said i take note of everything of every ride since '89 so i can definitely tell you when something changes as dramatically as my times have there IS something different.

as i said my times dropped by 5% AND average heartbeat dropped some beats too. not only on 1 single ride but several different ones with different lenghts too. no placebo here. just added speed!

and the "black art" you describe above is the ability to put all data together into 1 single package. that's where Michael Schumacher seems to be a master in. years of experience behind and that magic "golden hand" in finding the best setup for his formula 1 race car.


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## dovid (Apr 8, 2004)

What we need to do is put MBAction testers on various brands and types of tyre (with the brand name removed - can't forget that) and send them on laps around a course. Bingo! No placebo effect (they wouldn't know a fast tyre if it said specialized on it; they already don't know a slow tyre!)


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## Boj (Jan 13, 2004)

bonkey said:


> I really would've like to have seen not just a bunch of test rides, but a bunch of test riders. Then it would be a statistical inference to: "populations ride better with tires on terrain". That way we have an assessment of many riders with many abilities, and therefore could infer trends for everybody, instead of a singular riding group. This is the crux of my problem with this study. If anyone out there can findout how many rider samples there were and the number is a sample size worthy of science. I'll admit to my fault, and pray penance to the mtbr gods.


Hey, that's cool. Sorry if I was rude in my post. I take it a bit personal when randoms drop by to explain us our ignorance. And doesn't it happen often in this forum? 

I don't disagree about comfort. If a rider is experiencing softer ride, he rides faster and longer. It's been proven that FS bikes are faster than HT which is where I'll be going soon. I also don't disagree about comfort in confidence sense. The fastest tire is one you think is the fastest. I remember a scene from Days of Thunder when during a race the team manager on the radio tells Tom Cruise to go pass on the outside and that he had special grippy tires to do it. Tom pulls off the pass from the outside, wins the race but as it turns out, team manager was lying. Tom had regular tires, but he had confidence to go around thinking he had some extra edge.  Don't underestimate power of your mind.

You're still wrong about the German test though.


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## B R H (Jan 13, 2004)

*Have you tried your previous tires again though?*

Just curious if you have tried your previous, slower tires again to see if you also slow down by the same amount you initially gained with the NBX Lite. It would be a worthwhile test.


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## Chester (Jan 15, 2004)

*More tests on the Nokian advantage (from old post)*



nino said:


> could well be what you say BUT i ride my trails for 15 years and know them in and out. as i already said i take note of everything of every ride since '89 so i can definitely tell you when something changes as dramatically as my times have there IS something different.
> 
> as i said my times dropped by 5% AND average heartbeat dropped some beats too. not only on 1 single ride but several different ones with different lenghts too. no placebo here. just added speed!
> 
> and the "black art" you describe above is the ability to put all data together into 1 single package. that's where Michael Schumacher seems to be a master in. years of experience behind and that magic "golden hand" in finding the best setup for his formula 1 race car.


Several people have suggested you had the "placebo" effect. I suppose without some elaborate testing (double blind if that is even possible) we will never be completely certain. 
But just for a bit more "personal" information from a avid documentor of times on the same courses......For the enjoyment of the readers, many of whom many be new, I include a post I wrote about 2 years ago....
Not perfect testing but if you look at the amazing consistancy of my times over the various sections of the course, using the various tires, I am thinking that to some extent it backs up what Nino has been saying...

=================================================================
From about August or September of 2003....on the Weight board

In the past couple months Nino has given us some excellent first hand reports about the ride qualities of the new Nokian NBX Lite tires.
Grip, cornering, cushion, etc. as well as his perception of their ease of rolling resistance qualities. He has also supplied us with the German magazine tests for rolling resistance/watts.

Boj has supplied us with the formula for figuring out how much faster the Nokians would be, again "in theory"

Inspired by these writings, I got a Nokian NBX Lite to replace my front Specialized Roll-X Pro. I have now conducted extensive real world tests of the tires using a "robotic" rider. The "robotic" rider being ME, as I will explain further below....

First let me explain the bike setup and the test loop....
The bike is a 2003 Stumpjumper HT just under 23 pounds. The bike came with 2 Roll-X Pro tires but I had already replaced the rear one with a Performance (house brand) "Topo" SuperTrac MTB tire....a light tire similar in appearance to the Python Airlight.
My testing was conducted with the rear tire remaining constant ( the same Performance Topo tire......while I ran half (5) the runs with the Roll-X on the front and half (5) the runs with the Nokian NBX Lite on the front.

The test loop is a run I have done hundreds of times over the years. It is about 15 miles long with many hills, the last being about a 600 foot vertical climb over the final 7 minutes. 
Most of the loop is fireroads, though there is about 2 miles of paved path and about .15 miles of gravel. It is not a very technical loop but provides lots of hills for a great aerobic workout and is a good place to test the rolling resistance qualities in the real world.

I do the loop non-stop, always using the exact same tire pressure 
(48 rear, and 44 front) for both brands.
I ride the same days, M,W, Sat, and at the same time of day.
I always "push" during the entire run, although not at race pace, but still very fast, so I am never just cruising along.

I have six time checks ( 5 during the race and the final one at the finish) which I time with a stop watch and always at the same spot.

I'll now explain why I am almost a perfect "robotic" test rider.
The last timed section of the loop which is in the 18 minute range gives a good idea of just how consistant my riding is/was for this testing. Remember, I don't look at my watch until I finish the section....in other words, I am riding "blind" with regard to time during the section..
So take a look at this example section which is the last section and also the longest of the six.

Five runs with the Roll-X Pro
18:05, 17:54, 18:00, 17:56, 17:54, with the average of 17:57.8

Five runs with the Nokian NBX Lite
17:24, 17:23, 17:20, 17:21, 17:22 with the average of 17:22

Now you can see what I mean by ME being a "robotic" rider. Those 5 Nokian sections all came within 2 seconds of the average time. Even I was amazed with my consistant runs for that section, especially coming at the end of a hour long loop.
Even the Roll-X section runs only vary by a minimal amount ( 4 of the 5 within 4 seconds of the average and the 5th only 7 seconds off the average.

On the other five timed sections in the loop I was also extremely consistant although not quite as perfect as seen in that particular "2 second" Nokian group. Still amazingly steady and consistant.

Now for some results of switching one front 43.8 watt Roll-X Pro to one front 21.2 watt Nokian NBX Lite. (note, with the 22.6 watt savings, you have to modify it somewhat for the 40/60 weight split on the front/rear tires.....so take 80% of the 22.6 watt difference and multiply it by .80 for a approx. watt savings of about 18 watts.)
As I said for this test the rear tire remained constant.

Results (note different sections may have more or less climbing and down hill AND sections are not all of equal length)

Averages of 5 runs on Roll-X and 5 runs on Nokians

Section 1....9:38.6......9:16......(-3.90%)
Section 2....8:53........8:34......(-3.56%)
Secton 1+2..18:31.4.....17:50......(-3.69%)
Section 3....9:17.4......8:58......(-3.48%)
Section 4....6:57.8......6:39.4....(-4.40%)
(section 4 was all either flat or a climb...no downhill)
Section 5....7:21.4......7:10......(-2.58%)
Section 6...17:57.8.....17:22......(-3.32%)
Loop-All 1:00:05.4.... 57:59.4....(-3.49%)

Boj's formula predicted approx. 4.36% faster on flat ground. The one section that was flat plus some mild climbing was almost exactly that.

Remember, this is for one front tire only with the estimated adjusted watts

(note, at this point there may be more to this old post, but I can't find it. However the main points are included in what remains)


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## nino (Jan 13, 2004)

*excellent...*



Chester said:


> Several people have suggested you had the "placebo" effect. I suppose without some elaborate testing (double blind if that is even possible) we will never be completely certain.
> But just for a bit more "personal" information from a avid documentor of times on the same courses......For the enjoyment of the readers, many of whom many be new, I include a post I wrote about 2 years ago....
> Not perfect testing but if you look at the amazing consistancy of my times over the various sections of the course, using the various tires, I am thinking that to some extent it backs up what Nino has been saying...


thanks!
i guess most remain a bit sceptical when they hear you say " tire XY made me 5% faster"...i couldn't believe it myself at first but my experience and the data you provide here simply reflect what i have experienced too.
all this means is that RollingResistance indeed has much bigger effect than most might believe. TIME tells if a tire is fast. 
nevertheless most feel comfortable with a tire and will stick to it not knowing what they give up. i also had found my tires i would rely on. years of riding bikes and different brands of tires make you choose a tire that suits your needs best...i guess we are all equal here. but what makes a tire a "good tire? usually it's the way they behave out on the trails, how they grip in corners or how they perform tractionwise etcetc...but most don't look at the stopwatch when selecting a tire. me either. i always thought they are more or less equal and some offer better grip and are therefore a bit slower in RR while others have less knobs (semislicks) and might be faster on the flats while loosing time on the technical stuff....

so when that RR test was printed in summer 2003 with that Nokian beeing fastest and with comments like "quadration of the circle" because it was not only the fastest but also offering excellent grip almost everywhere i thought i might give it a try. without that test i most probably would never have used a Nokian tire in my whole life. why should i? i was happy with the tires i was running. but man i was surprised when i looked at my stopwatch...i mean, i ride bikes for over 15 years. you spend countless hours in the saddle, log down each ride and measure heartrates etc. and each year you can see how you get in shape slowly but this tire made such a huge improvement at once it was unreal. it's like beeing doped or what? call it "placebo" or whatever you feel comfortable.. i can only say it's fast!!

now this new scientific test , while beeing interesting to a certain degree, takes into account only RR completely isolated from all other factors. there's some truth in it but for real world biking there's not too much valuable info in it. there's too many factors having big impact in overall speed of a tire too.

but you bet i will have a look at a wider tire in the near future. i guess it will most likely be a Schwalbe Racing Ralph 2.25 or even 2.35. just the fact these weigh over 500g makes me shiver though and so far the racing ralph wasn't on my list as it doesn't perform good once trails become humid/wet and that's what we have pretty much over here in Switzerland. my tires need to have excellent grip everywhere AND be decent in weight AND fast ! sounds as a "quadration of the circle", right ? well - that's what the Nokian is for me.

TIME will tell if i'm even faster on a "underinflated" 2.3" tire.

i'll keep you updated.


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## Fast1000 (May 23, 2005)

I am shocked that the test showed the larger 2.25 RacingRalph scored a lower rolling resistance than the 2.1 RacingRalph.
Darn, I just bought two 2.1 RR's for racing.  

Last year I raced on Mich Comp lites and loved them on the straights. I had bad luck when I went with Stans with them because the side walls are so porous!
I almost bought the nbx lites but I read that they are not recommended to use with the Stans!


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## Chester (Jan 15, 2004)

*It might be a mistake or misprint.*



Fast1000 said:


> I am shocked that the test showed the larger 2.25 RacingRalph scored a lower rolling resistance than the 2.1 RacingRalph.
> Darn, I just bought two 2.1 RR's for racing.
> 
> Last year I raced on Mich Comp lites and loved them on the straights. I had bad luck when I went with Stans with them because the side walls are so porous!
> I almost bought the nbx lites but I read that they are not recommended to use with the Stans!


I noticed that irregularity when those results first were posted in the orginal thread about that German magazine article a couple years ago ( I think). This thread just included that same chart again.
I believe at some point I raised this point of the 2.25 being lower than the 2.1......and I don't think a good answer was ever given.

Perhaps someone will give us a better answer.

However, be careful someone doesn't misinterpret this unusual data and mix it up with the results earlier in this thread that show "on some surfaces" that a wider tire rolls faster.
The tests involving the 2.1 and 2.25 in this case were conducted on a steel roller.


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## cmv96 (Aug 19, 2004)

nino said:


> from what i've heard it's too heavy for my taste. it think something around 550-580g. and i'm so satisfied with my NBX 2.0 that i won't change it too soon...


Nino, just curious whether you've ever personally trail-tested the 2.0 Racing Ralph against your Nokian's and what those results were.


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## nino (Jan 13, 2004)

cmv96 said:


> Nino, just curious whether you've ever personally trail-tested the 2.0 Racing Ralph against your Nokian's and what those results were.


there's no 2,0" RR. just 2,1"

that's pretty easy to answer:
the RR has little grip so as soon as you have some thechnical riding involved you are lost. no braking grip,no sidegrip going into corners compared to the Nokian.

I used a 2,25" RR last summer and used with tubelesskit and very low pressure this is a sweet tire for dry terrain. it rolls very good and it's size gives superb comfort on a HT. grip of the 2,25" is also better than the 2,1". Schwalbe tires not only get wider with size but also the knobs get taller! so the wider RR has definitely better grip than the 2,1.

BUT
the Nokian is still faster rolling

BUT
the Schwalbes are lighter and very close in rollingresistance. i was able to pick light tires at the swiss distributor and could find a 476g Racing Ralph 2,25". Nokians nowadays are close to 500g and have rather slim size the lightest 2,1" Racing Ralph i could find weighed 447g.

Racing Ralphs definitely are REAR only. the Nokian as excellent grip and is very fast rolling.


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## cmv96 (Aug 19, 2004)

nino said:


> there's no 2,0" RR. just 2,1"
> 
> the RR has little grip so as soon as you have some thechnical riding involved you are lost. no braking grip,no sidegrip going into corners compared to the Nokian.
> 
> ...


I agree that the 2,1" RR lacks adequate grip as a front tire. I've been running the 2,1" RR as a (tubeless) rear tire for a couple years now and I'm still trying to find the best tire in the front. Nino, after reviewing these German magazine test results again, I'm curious why you still maintain that "the Nokian is still faster rolling". I'm not debating it, just curious how you arrived at that conclusion when the magazine shows different.
Also, have you found the NBX lite 2.0 to have adequate grip and braking power in the front, as opposed to the 2.2? Not sure I can even find the 2.2 here in the states, so I'm thinking a Racing Ralph 2.25 in the front may be the way to go.


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## nino (Jan 13, 2004)

cmv96 said:


> I agree that the 2,1" RR lacks adequate grip as a front tire. I've been running the 2,1" RR as a (tubeless) rear tire for a couple years now and I'm still trying to find the best tire in the front. Nino, after reviewing these German magazine test results again, I'm curious why you still maintain that "the Nokian is still faster rolling". I'm not debating it, just curious how you arrived at that conclusion when the magazine shows different.
> Also, have you found the NBX lite 2.0 to have adequate grip and braking power in the front, as opposed to the 2.2? Not sure I can even find the 2.2 here in the states, so I'm thinking a Racing Ralph 2.25 in the front may be the way to go.


the Nokian NBX Lite 2,0" is still the fastest!

i guess you refer to one of my scans in the Speed King thread, right? there they show numbers for a Nokian NBX "S" (S stands for semislick!!). that was a different tire than the one i am talking about!
http://forums.mtbr.com/showthread.php?t=296335

the 2,2" NBX is not available in a "light" version. it also rells pretty fast but not near as fast as the slimmer 2,0". it offers excellent grip as well but the weight is definitely too much.

as a front tire i'd suggest:
Conti Speedking 2,1" (lightest at around 400g, excellent grip,rather slim,no fast cornering on paved roads! a bit nervous in gravel (slim size)
Conti Speedking 2,3" (very fast,very light,excellent grip,more cushion than the 2,1, not best on paved roads, just around 430g!)
Nokian NBX Lite 2,0" (fastest,excellent grip, no rocks with the Nokian NBX, cuts easily, weighs from 450-510g)
Schwalbe Nobby Nic 2,1" (best do it all with good bite, pretty fast, bigger volume than the Speed King 2,1", weigh before you buy!! they vary 80g within the same size!! lightest ones are around 450-460g)


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## cmv96 (Aug 19, 2004)

nino said:


> BUT
> the Schwalbes are lighter and very close in rollingresistance. i was able to pick light tires at the swiss distributor and could find a 476g Racing Ralph 2,25". Nokians nowadays are close to 500g and have rather slim size the lightest 2,1" Racing Ralph i could find weighed 447g.
> 
> Racing Ralphs definitely are REAR only. the Nokian as excellent grip and is very fast rolling.


man, those are light! must have some v thin sidewalls...difficult to seal as tubeless?


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## nino (Jan 13, 2004)

cmv96 said:


> man, those are light! must have some v thin sidewalls...difficult to seal as tubeless?


no problem given you have a powerful compressor


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## cmv96 (Aug 19, 2004)

nino said:


> the 2,2" NBX is not available in a "light" version. it also rells pretty fast but not near as fast as the slimmer 2,0". it offers excellent grip as well but the weight is definitely too much.


huh? The Nokian website show the NBX Lite available in the 2,2" (550g), doesn't it?
http://www.suomityres.fi/lite.html


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## nino (Jan 13, 2004)

*wow-correct...*



cmv96 said:


> huh? The Nokian website show the NBX Lite available in the 2,2" (550g), doesn't it?
> http://www.suomityres.fi/lite.html


that must be pretty new. i have never seen the Light so far. but anyway, at well over 550g (make that close to 600) this is not a tire i would mount on my bike. i already had a hard time convincing myself to mount the 2,25" Nobby Nic on the rear when i spent 1 week in italy but at least on a HT you get superb comfort and grip. but on the front i would never mount such a heavy tire.


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## Walter C (Jan 22, 2004)

I run the 2.2 nbx wire bead on the rear, and it is a very fast tire. Faster than the spider 2.1 I had and better grip. I certainly dont notice the weight and I never worry about the wire bead blowing off the rim. [ztr-btw].


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## cmv96 (Aug 19, 2004)

nino said:


> Racing Ralphs definitely are REAR only. the Nokian as excellent grip and is very fast rolling.


Just picked up some '07 Racing Ralphs. The one 2.1" I bought weighed 435 grams and the lightest 2.25" (out of 4 tires) weighed 525g.


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