# why have a 6 inch rotor on the rear wheel?



## hab1b (Jan 15, 2007)

I have seen this around and do not understand it. educate me.


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## SHIVER ME TIMBERS (Jan 12, 2004)

a general rule of thumb is.....the front brake is for stopping and the rear brake is for steering

IMO if you are under 180pounds then you really don't see the difference of stopping power (it is there though) ...when you start getting in to the 200's you KNOW the difference


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## hab1b (Jan 15, 2007)

yea i knew that most of your braking power is in the front and not soo much the rear. i am 160 pounds run two 8 inch rotor i think ill stick with it. i was not sure if the 6 inch was just to save a little weight or what.

edit: how many of you guys run a 6 inch in the back and a 8 inch up front?


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## blender (Oct 28, 2005)

what he said...

a smaller rotor will save you rotational weight.. if you're a light guy you won't notice a difference in braking performance, but might notice the slight weight savings.


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## mtb_biker (Jan 27, 2004)

it also depends on your terrain, length of runs, speed, what kind of brakes you have, how you brake, what you want your brakes to do, and weight


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## EliM (May 6, 2006)

I do, but the only reason I have a six incher in the back is because my frame doesn't have enough room for an 8. 
I only weigh 120 w/o gear so theres not really any need for an 8 inch rotor on the back.


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## SHIVER ME TIMBERS (Jan 12, 2004)

hab1b said:


> yea i knew that most of your braking power is in the front and not soo much the rear. i am 160 pounds run two 8 inch rotor i think ill stick with it. i was not sure if the 6 inch was just to save a little weight or what.
> t?


weight difference is minimal........I would bother wasting my time switching back


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## crisillo (Jul 3, 2004)

mostly for weight savings...


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## euroford (Sep 10, 2006)

i initially ran 8" f & r, but the frame clearance on the 8" rotor was rather slim. so i tried out a 6" rotor in the rear and found that not only did it have more than enough power, but that it was easier to modulate and avoid lockup.


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## dandurston (Jan 20, 2005)

Anyone care to guess what the weight difference is? You'd save the adapter (maybe 35g?) and some rotor weight (75g?) so maybe 100g total?

I'm 160lbs and I run dual 8" Avid BB7. They offers about as much stopping power as 7" hydros at a lighter weight. A 160mm Juicy brake is atleast 420g/wheel whereas a 160mm BB7 brake is 318g/wheel.

Everyone seems to be dimissing mechanical brakes these days because hydros offer slightly more power but it seems to make way more sense to just go 1 inch larger in diameter with mechs and then you are running a setup that's cheaper, lighter, way easier to work on, more reliable and it doesn't cost $100 when you crash and trash a lever.

Avid's new FR/DH brake (the Code) is 561g/wheel for an 7" brake and my similarly powerful 8" BB7's weigh around 370g. The difference is a full pound off my bike and $350 in my pocket.


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## crisillo (Jul 3, 2004)

dandurston said:


> I'm 160lbs and I run dual 8" Avid BB7. They offers about as much stopping power as 7" hydros at a lighter weight. A 160mm Juicy brake is 411g/wheel whereas a 160mm BB7 brake is 318g/wheel.


Very few hydros will weigh more than the bb7... avid's claimed weights don't include the levers, housing and cables, so it is likely that the hydros will be lighter with the same size rotors...


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## dandurston (Jan 20, 2005)

crisillo said:


> Very few hydros will weigh more than the bb7... avid's claimed weights don't include the levers, housing and cables, so it is likely that the hydros will be lighter with the same size rotors...


I disagree but I wish there was a website or something that had more complete information. Consider a mechancial brake vs a hydro:

*Rotor*: Equal because you can use any rotor for either
*Lever*: Advantage BB7...you can run any levers but it's easy to get levers for 150g for a pair which I doubt any hydro can touch since you've got a reseviour of fluid weighing things down.
*Lines:*: Advantage BB7. Cables are lighter than fluid because you've got a lot more fluid...the cable is maybe 2-3mm in diamater vs. about 4mm of fluid.
*Caliper:* This likely varies a lot by model...can't really generalize on this one as the weight isn't inherant to being mech or hydro.

Anyways, unless you're on a factory supported team, mechs just seem to make so much more sense in the real world . I crashed this summer and mangled a lever and picked up a new pair for $13 on Pricepoint (so I have an extra). Back when I was running Magura hydro's I also crashed and busted a lever and had to shell out about $130 for a new one. My point is that you can get similar braking performance at no weight penality in a package that's a lot simpler and cheaper to maintain. Maybe you can find a hydro that's slightly lighter if you look up around $300/wheel but I just don't see a good reason to sell out the extra $225 for a high maintenance system.


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## 08nwsula (Oct 19, 2005)

I ride 8 in front a six in back. I will take the clearance in the rear rather than the stopping power. Even at 200 pounds, I would still rather keep the 8 inch for the front only.


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## crisillo (Jul 3, 2004)

dandurston said:


> I disagree but I wish there was a website or something that had more complete information. Consider a mechancial brake vs a hydro:
> 
> *Rotor*: Equal because you can use any rotor for either
> *Lever*: Advantage BB7...you can run any levers but it's easy to get levers for 150g for a pair which I doubt any hydro can touch since you've got a reseviour of fluid weighing things down.
> ...


well I have a digital scale and put my old bb7s without rotors and adapters (but with housing and avid speed dial levers) and compared them to the complete set of LX hydros on my SS and they were still lighter than the bb7s by about 50 grams with the hoses uncut (and full of fluid of course)... and the LX is not exactly a "light" hydro


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## DHidiot (Aug 5, 2004)

A lot of frames that aren't full on DH frames don't have a wide enough spacing in the chainstay to accomodate an 8" rotor. This applies to mostly older frames since I think most everyone has caught onto that trend. 

The smaller rotors are less prone to warping too, or if they do warp they bend a lot less which could be the difference in clearing the pads and an unholy irritatting rubbing sound.


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## captain spaulding (May 7, 2006)

dandurston said:


> I disagree but I wish there was a website or something that had more complete information. Consider a mechancial brake vs a hydro:
> 
> *Rotor*: Equal because you can use any rotor for either
> *Lever*: Advantage BB7...you can run any levers but it's easy to get levers for 150g for a pair which I doubt any hydro can touch since you've got a reseviour of fluid weighing things down.
> ...


This has been beaten to death in the weight weanie forum, bottom line hyrdo brakes are lighter, when comparing similar braking systems. IE you wouldn't compare the BB7's to codes as they are designed to do different things, you would compare the BB7's to say Juicy's as they are designed to do pretty much the same thing. I have bb7's on my trail bike and codes on my FR bike, and I can say the power and modulation is far superior on the codes, at the price of a weight penalty. Before I built my FR bike I rode my trail bike at Plattekill(ski resort / bike park in NY) and the BB7's just couldn't stop me good enough and were downright scary in some situations although they were a huge improvement over my old hayes h-mx's. maybe it's cause i'm heavy/clydesdale-ish but I just won't do mechanicals again on a something i'll be flying down a hill at breakneck speed.

but on the topic of smaller rear brakes, it's just really to save weight, save costs, as your front wheel is doing most of the braking, additionally, I'm sure there is less brake jack with a smaller rotor vs. a bigger rotor. If i had the choice for a smaller rotor on the back i would have done it, but the deal i got it didn't matter..


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## dandurston (Jan 20, 2005)

crisillo said:


> well I have a digital scale and put my old bb7s without rotors and adapters (but with housing and avid speed dial levers) and compared them to the complete set of LX hydros on my SS and they were still lighter than the bb7s by about 50 grams with the hoses uncut (and full of fluid of course)... and the LX is not exactly a "light" hydro


Sorry I'm unclear on this. Are you saying:

BB7 Caliper + Housing and Cable + Speed Dial Levers is 50g heavier than:

LX Caliper + Housing and Fluid + LX Levers + Adapter?

An Avid BB7 brake is spec'd at 318g which includes the lever and caliper. From what I can tell, the 160mm rotor is around 130g which means that the caliper is 188g which is exactly what Shimano has the LX caliper and adapter spec'd at. This means that the we can essentially remove the rotors, adapter and calipers from this equation since they are equal which means that:

Housing and Cable + Speed Dial levers is 50g more than:

Housing and Fluid + LX Levers

Unfortunately I can't find the information to investigate this further but if you wanted to you could just switch to the Avid FR5 levers which makes up for the supposed difference right there and/or switch to using shifter cables to put the mech ahead.


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## dandurston (Jan 20, 2005)

captain spaulding said:


> This has been beaten to death in the weight weanie forum, bottom line hyrdo brakes are lighter...the BB7's just couldn't stop me good enough.


I realize this topic that has been beaten to death many times so the only two comments I'll make are:

1 - where you using 8" BB7's?
2 - My point is that mechs can be had at a similar weight and power-level as hydro's yet they are much cheaper and simpler to use. If you compare an 8" BB7 to a 7" Juicy you'll find the total weight and power is very similar yet the BB7's are way cheaper and easier to use.


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## crisillo (Jul 3, 2004)

dandurston said:


> Sorry I'm unclear on this. Are you saying:
> 
> BB7 Caliper + Housing and Cable + Speed Dial Levers is 50g heavier than:
> 
> ...


The 318g weight includes the caliper, 160mm rotor and 160mm adapter (no lever, the box doesn't include levers), my 160mm rotors weigh about 95-100 grams.

I weighed the brakes as levers, hose/cable-housing, and caliper...the difference in the front one was about 15 grams and the rear one was about 30-35 grs with the hoses uncut and full (I didn't write the exact numbers down, sorry).

Personally I am not interested in having a lighter mech as I prefer the hydro feel at the lever, which takes more maintenance (cable switch) to preserve over time on the bb7s... that's exactly why I switched the bb7s for LXs...


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## cranberry (Nov 15, 2005)

My rig doubles as my DH and my FR rig. I run a 6" rear because I was tired of bending 8inchers in rock gardens and slipping off of skinnies. I went to a 6 on the rear a year or so ago and I haven't bent one since.
Now that I said that, I'll bend it on the next ride.


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## tempest229 (Feb 5, 2007)

You have to consider the momentum of having the weight on an 8 vs a 6 inch radius


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## jtd (Jan 12, 2004)

It really depends on the terrain. I run a 6" because of the added cleareance it gives me. As it stands with a 6" rotor I bend about 5 a year falling off skinnies or bashing it on something. I can't imagine how many I would bend with an 8"...

I don't notice a difference in braking force between the 2 sizes either...

Jake


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## DHidiot (Aug 5, 2004)

For christsake if you are on a bike that you even think you can put an 8" rotor on you will NOT notice an f'ing weight difference. You will notice a weight diffference in tires and tubes and rims, not a few grams 3-4" away from your axle. If you think you can, buy a road bike and some spandex.


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## tacubaya (Jan 27, 2006)

Damn you weight weenies :madman:


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## crisillo (Jul 3, 2004)

tacubaya said:


> Damn you weight weenies :madman:


yeah Tacu, that's why after comparing the weights I got a 203mm rotor on the front LX to make up for the difference again :lol:


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## BikeSATORI (Mar 20, 2004)

dandurston said:


> I realize this topic that has been beaten to death many times so the only two comments I'll make are:
> 
> 1 - where you using 8" BB7's?
> 2 - My point is that mechs can be had at a similar weight and power-level as hydro's yet they are much cheaper and simpler to use. If you compare an 8" BB7 to a 7" Juicy you'll find the total weight and power is very similar yet the BB7's are way cheaper and easier to use.


yeah, your points here have been beaten to death... to where they are no longer sharp, just dull... face it. this isn't the thread to debate mech vs. hydro anyway...

I use a 160mm rotor in the back of most all my rigs (2 monoM4's/1monomini/1avidBB7 - all on different bikes of course) with the occasional 180 going onto the rear of my DH/FR bike...
I'd agree with euroford, as well as cranberry and the others who mentioned better gnar clearance w/ 6in...
I guess instead of just asking "why 6in. in the rear?" you could also ask, "why 8in in the rear?" different people ride different stuff...


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## Karupshun (Jun 13, 2006)

captain spaulding said:


> as your front wheel is doing most of the braking, additionally, I'm sure there is less brake jack with a smaller rotor vs. a bigger rotor. If i had the choice for a smaller rotor on the back i would have done it, but the deal i got it didn't matter..


can someone confirm if a 6" rotor would reduce jack?

I am about to upgrade to some codes on my chaparral. If a 6" indeed reduces jacking, I'm sure the 6" rotor will still have more than enough stopping power for me.

the added bonus of less disc-bending sounds pretty cool too


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## captain spaulding (May 7, 2006)

dandurston said:


> I realize this topic that has been beaten to death many times so the only two comments I'll make are:
> 
> 1 - where you using 8" BB7's?
> 2 - My point is that mechs can be had at a similar weight and power-level as hydro's yet they are much cheaper and simpler to use. If you compare an 8" BB7 to a 7" Juicy you'll find the total weight and power is very similar yet the BB7's are way cheaper and easier to use.


1 - yes, I was, but like I said I'm a big guy(6' 4" 210) and that's probably more to do with it then anything else.


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## captain spaulding (May 7, 2006)

Karupshun said:


> can someone confirm if a 6" rotor would reduce jack?
> 
> I am about to upgrade to some codes on my chaparral. If a 6" indeed reduces jacking, I'm sure the 6" rotor will still have more than enough stopping power for me.
> 
> the added bonus of less disc-bending sounds pretty cool too


I really don't have a conclusive answer for this one, but logically if you're exerting less force on the swingarm with a smaller rotor that has less mechanical advantage than a bigger a rotor, the brake jack effect would be less.. in theory of course..


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## euroford (Sep 10, 2006)

tacubaya said:


> Damn you weight weenies :madman:


yeah i hear that.... but.... did i notice the weight diffrence of my rotor? no not really. but after doing the rotor, the rear skewer, the spokes, the nips, a couple of bolts, hacking off the seatpost, and a couple of other items i ended up with a really nice cumulative savings without loosing the burl that i need the ride to have. freeride is not the place to be a weight weeny, but some smart choices sure give ya a better riding rig. especially around here were our pedaling to playing ratio is kinda crummy.


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## njhcx4xlife (Jan 9, 2006)

Karupshun said:


> can someone confirm if a 6" rotor would reduce jack?
> 
> I am about to upgrade to some codes on my chaparral. If a 6" indeed reduces jacking, I'm sure the 6" rotor will still have more than enough stopping power for me.
> 
> the added bonus of less disc-bending sounds pretty cool too


I HIGHLY doubt the rotor size would have anything to do with brake jack. it is the same forces being applied to the suspension with either size rotor.


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## XSL_WiLL (Nov 2, 2004)

dandurston said:


> Anyone care to guess what the weight difference is? You'd save the adapter (maybe 35g?) and some rotor weight (75g?) so maybe 100g total?
> 
> I'm 160lbs and I run dual 8" Avid BB7. They offers about as much stopping power as 7" hydros at a lighter weight. A 160mm Juicy brake is atleast 420g/wheel whereas a 160mm BB7 brake is 318g/wheel.
> 
> ...


While BB7s are very good brakes, they don't even come close to touching the Codes.


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## Karupshun (Jun 13, 2006)

captain spaulding said:


> I really don't have a conclusive answer for this one, but logically if you're exerting less force on the swingarm with a smaller rotor that has less mechanical advantage than a bigger a rotor, the brake jack effect would be less.. in theory of course..


In theory, communism works....In 'theory'


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## Karupshun (Jun 13, 2006)

njhcx4xlife said:


> I HIGHLY doubt the rotor size would have anything to do with brake jack. it is the same forces being applied to the suspension with either size rotor.


same lines I was thinking...


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## Ace1 (Jun 14, 2004)

Monetary savings.
Weight savings.
Harder to lock up rear.


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## hab1b (Jan 15, 2007)

my question was answered within the first 2-3 replies. i dont like mech brakes because every pair i had always got sticky on me. so id rather not deal with it.


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## Huck Banzai (May 8, 2005)

Why bother? I dunno.

Old argument - but properly set up brakes - BB7's are great - but if you think they are anywhere near as strong as any quality hydro - you're either 100lbs or insane.

Codes are ridiculous - I'll run a 6" rotor - you can run a 10" - and you wont touch em.


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## dstudentx (Oct 12, 2005)

Sam Hill runs a 6" and Peaty runs a 7" now 
This coming season most of the pros will run 7" rotors


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## Freerydejunky (Sep 21, 2006)

Comming from 6" XC rotors going to full on 8" hayes 9's it makes a big difference for me (at 105lbs  ) The initial bite it way stronger. At least thats what I think. I think the sickest rotor out there is this baby Red Raven 9"
I dont care if it sucks it looks sick!


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## wayodh (Nov 13, 2004)

In longer rides as the ones we have in Peru, you will notice the difference between 6 and 8 inch rotors!
Imagine going down from 4,000 masl to the sealevel! Inclusive 8 inch rotors fail at certain parts of the trails.


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## LarryFahn (Jul 19, 2005)

dstudentx said:


> Sam Hill runs a 6" and Peaty runs a 7" now
> This coming season most of the pros will run 7" rotors


Well there's your answer!

If the pros are doing it, I better start doing it too!


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## Karupshun (Jun 13, 2006)

motormonkeyr6 said:


> Comming from 6" XC rotors going to full on 8" hayes 9's it makes a big difference for me (at 105lbs  ) The initial bite it way stronger. At least thats what I think. I think the sickest rotor out there is this baby Red Raven 9"
> I dont care if it sucks it looks sick!


They look almost as bad as the hope gothics.

I can imagine how awesome it's going to be to bolt another adapter ONTOP of your 8" adapter


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## Rover Nick (Jul 13, 2006)

DHidiot said:


> For christsake if you are on a bike that you even think you can put an 8" rotor on you will NOT notice an f'ing weight difference.


Enough grams turn into ounces. ounces turn into pounds. Most likey you will notice pounds off your bike


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## Zonk0u (Jun 3, 2004)

I like a 6 in the back for modulation. rear for steer is my motto. I've ridden 8's and didn't like the feel. I've never had a problem locking it up with the 6 so I dont really see why I'd need an 8 and Im 250lbs.


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## DHS (Jan 14, 2004)

dandurston said:


> I disagree but I wish there was a website or something that had more complete information. Consider a mechancial brake vs a hydro:
> 
> *Rotor*: Equal because you can use any rotor for either
> *Lever*: Advantage BB7...you can run any levers but it's easy to get levers for 150g for a pair which I doubt any hydro can touch since you've got a reseviour of fluid weighing things down.
> ...


um, i've gone and weighed Hope Mono 6ti front and rear vs Avid bb7s with levers and cables. the hopes were almost a half pound light. cables and housing are much heavier then kevlar lines and fluid


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## hab1b (Jan 15, 2007)

well this is the first 8inch ive had on the rear and i have noticed that it locks up quicker.. i am not a fan of that. i think i will buy a 6 inch rotor and try it out. rotors are not too much $$ so it could worth it.


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## Freerydejunky (Sep 21, 2006)

dstudentx said:


> Sam Hill runs a 6" and Peaty runs a 7" now
> This coming season most of the pros will run 7" rotors


Maybe because he doesnt brake


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## konut (Mar 25, 2006)

i,m,o 6 inch rotors are there for the simple reason of when you brake your weight is transfered forward onto the front anyways.

the whole point of hydros over mechanicals was to do away with the inherent problems of cable stretch and sticky lines.

and no you wont feel the difference in rotational mass with a larger disc but your suspension will as your disc is unsprung mass and affects the suspension ability to work effectvley.

and like i said this is my opinion


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## LarryFahn (Jul 19, 2005)

Rover Nick said:


> Enough grams turn into ounces. ounces turn into pounds. Most likey you will notice pounds off your bike


OMG! Does that mean that my Super Gnar will eventually weigh nothing?!!! YES, I've been waiting for this!

For the extra grams you're adding, you can stop 300 lbs a lot quicker. It's a DH bike. A pound doesn't mean anything when you weigh more than the bike. Argue as much as you want, but grams aren't even noticeable.


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## SylentK (Aug 9, 2004)

I'm running two 8" rotors on my Nomad (built for light DH/FR) and I'm always locking up the rear wheel and not on purpose. I'd def like to switch to a 6", but I got more pressing mtb parts to buy with my $$$. 

I would have to say that I DO think 8" rotors contribute to brake jack more than a 6" rotor. Due to mechanical advantage. Think about it like a lever pulling up on your rear suspension. Is it easier with a longer lever or shorter?


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## solarburn (Jun 27, 2005)

*BB7's are a good set up!*

Cable stretch is easier to deal with than bleeding hydros. Sticky lines are only problamatic with certain cable routing on various bikes or its just time to do it. I suffer none of these conditions on both my sleds. I have the cables housed front to back so no contamination and no hard bends. I change out the cables generally 2x a season. Takes 5 minutes. I weigh 220 and have as much power as any hydros I've used minus Gustav's. 1 finger pull on the lever. Doesn't need to be any better than that for me. Modulation is fine.

I just switched to having a 6 in the back and 8 in the front on one of my sleds. The other has 7 & 7. Both versions work and I don't feel short changed on the 6 & 8. Another good point is that its out of the way and won't get bent as easily as the bigger rotors.


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## Ace1 (Jun 14, 2004)

konut said:


> i,m,o 6 inch rotors are there for the simple reason of when you brake your weight is transfered forward onto the front anyways.
> 
> and no you wont feel the difference in rotational mass with a larger disc but your suspension will as your disc is unsprung mass and affects the suspension ability to work effectvley.


Hmmm not sure.

I think the effect of the difference in rotational mass and the effect on your suspension will both be infinitesimal.

I think like any bike weight-related issues, you can get a bit anal on the effect of shedding a couple of grams - skip breakfast or take a piss before you ride - the effect will be far greater!

Maybe the weight saved allows you to brake later and ride better over mud :thumbsup:


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## Zonk0u (Jun 3, 2004)

konut said:


> i,m,o 6 inch rotors are there for the simple reason of when you brake your weight is transfered forward onto the front anyways.
> 
> the whole point of hydros over mechanicals was to do away with the inherent problems of cable stretch and sticky lines.
> 
> ...


you're not going to notice the gram or so difference in unsprung weight.


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## Zonk0u (Jun 3, 2004)

SylentK said:


> I'm running two 8" rotors on my Nomad (built for light DH/FR) and I'm always locking up the rear wheel and not on purpose. I'd def like to switch to a 6", but I got more pressing mtb parts to buy with my $$$.
> 
> I would have to say that I DO think 8" rotors contribute to brake jack more than a 6" rotor. Due to mechanical advantage. Think about it like a lever pulling up on your rear suspension. Is it easier with a longer lever or shorter?


in speculation, the brake jack isnt going to be any different, because when it comes down to it you're still using the same amount of force to stop with. with the bigger rotor, you're just pulling the lever softer. the forces and momentum you're acting on dont really change. you're still carrying the same weight at the same speed in the same direction, and trying to slow down at the same traction threshold before lockup.


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## konut (Mar 25, 2006)

i personaly feel the torque is better,in a way that the power is more usable


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## dbabuser (Jan 5, 2004)

LarryFahn said:


> For the extra grams you're adding, you can stop 300 lbs a lot quicker. It's a DH bike. A pound doesn't mean anything when you weigh more than the bike. Argue as much as you want, but grams aren't even noticeable.


A pound added to or subtracted from the bike *would* mean less if it was attached to your torso. Instead, it's out at the ends of your appendages, which gives it a bit of leverage. On top of that, any rotational mass has to both stop and start a bit on every corner. Add up these effects at the bottom of a race run when you can barely breathe, and THAT is why the pros are worrying about how much their bikes weigh. 
For the rest of us, it all depends on how serious you are. If you're a 300 lb'er doing cruiser runs down the mountain, then no, it's most likely not worth it for the performance advantage. Don't think just because you can't tell and it's not important to you that it shouldn't matter to anybody.


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## Karupshun (Jun 13, 2006)

solarburn said:


> Cable stretch is easier to deal with than bleeding hydros. Sticky lines are only problamatic with certain cable routing on various bikes or its just time to do it. I suffer none of these conditions on both my sleds. I have the cables housed front to back so no contamination and no hard bends. I change out the cables generally 2x a season. Takes 5 minutes. I weigh 220 and have as much power as any hydros I've used minus Gustav's. 1 finger pull on the lever. Doesn't need to be any better than that for me. Modulation is fine.


I really have to disagree. I find myself spending an amazing amount of time working on my mechanical brakes to maintain any sort of acceptable stopping power. especially on the trail tunging the fine-adjusts all the time. Good hydros need to be bled once a year if done correctly.

granted I use Hayes MX-1s but I am your size. I run them on 8" Saint discs with kool-stop semi metallic pads. The brake fade on the organic pads & stock hayes rotors were a joke on any sort of long decent regardless of grade.

saying bb7s are as good as any hydro other brake beside the Gustav is naieve The force applied through hydraulic pressure from the brake booster to the piston is many times greater than the leverage ratio granted on even the best mechanical levers. Maybe your gigantic man-hand has the power to never fatigue and one-finger it, but mine are normal human-hands that get tired. I think you need to find some long, tight, fast, and technical single track and take a new look at hydros


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## fsrxc (Jan 31, 2004)

Ace1 said:


> Monetary savings.
> Weight savings.
> Harder to lock up rear.


Modulation doesn't actually change, so 8"s will lock up easier only because there's more power/leverage.


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## dandurston (Jan 20, 2005)

Karupshun said:


> I really have to disagree. I find myself spending an amazing amount of time working on my mechanical brakes to maintain any sort of acceptable stopping power. especially on the trail tunging the fine-adjusts all the time. Good hydros need to be bled once a year if done correctly.
> 
> granted I use Hayes MX-1s but I am your size. I run them on 8" Saint discs with kool-stop semi metallic pads. The brake fade on the organic pads & stock hayes rotors were a joke on any sort of long decent regardless of grade.
> 
> saying bb7s are as good as any hydro other brake beside the Gustav is naieve The force applied through hydraulic pressure from the brake booster to the piston is many times greater than the leverage ratio granted on even the best mechanical levers. Maybe your gigantic man-hand has the power to never fatigue and one-finger it, but mine are normal human-hands that get tired. I think you need to find some long, tight, fast, and technical single track and take a new look at hydros


The problem is your Hayes MX-1's. I spend maybe 30 seconds every couple weeks moving my pads in a click and I can easily 1 finger lock up my BB7's. I'm considering switching them to 6"'ers (from 8") because I don't need the power. I could be wrong about the whole 'leverage ratio' concept but I don't think there's a significant difference in the actual ratio here. The difference in power between mechs and hydro's comes from some of your power being absorbed by cable stretch with mechs whereas hydro's use uncompressable fluid so 100% of your power is transfered compared to 90-95%. The rotor diameter seems to be a much bigger factor than whether it's a mech or a hydro in terms of potential stopping power.


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## fsrxc (Jan 31, 2004)

SylentK said:


> I'm running two 8" rotors on my Nomad (built for light DH/FR) and I'm always locking up the rear wheel and not on purpose. I'd def like to switch to a 6", but I got more pressing mtb parts to buy with my $$$.
> 
> I would have to say that I DO think 8" rotors contribute to brake jack more than a 6" rotor. Due to mechanical advantage. Think about it like a lever pulling up on your rear suspension. Is it easier with a longer lever or shorter?


Brake lockup can be affected by many factors other than rotor size,

Pad material
Rotor condition (pad transfer can make them grabby)
Brakes (some modulate better than others)
Lever pull - are you using 1 or 2 fingers? (1 finger modulates better usually)
Rear tire! - some tires skid easier than others - I found a DH24 on the back on loose stuff locked very easily, but a High roller modulated better.
Weight distribution - how you're balanced when braking can make a huge difference, especially on a steep downhill.

Anyway, just pointing out your lockup problem may not be instantly fixed by going to a smaller rear rotor.


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## mtb_biker (Jan 27, 2004)

dandurston said:


> The problem is your Hayes MX-1's. I spend maybe 30 seconds every couple weeks moving my pads in a click and I can easily 1 finger lock up my BB7's. I'm considering switching them to 6"'ers (from 8") because I don't need the power. I could be wrong about the whole 'leverage ratio' concept but I don't think there's a significant difference in the actual ratio here. The difference in power between mechs and hydro's comes from some of your power being absorbed by cable stretch with mechs whereas hydro's use uncompressable fluid so 100% of your power is transfered compared to 90-95%. The rotor diameter seems to be a much bigger factor than whether it's a mech or a hydro in terms of potential stopping power.


hydro's offer a mechanical advantage that cable's just can not compete with.


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## Karupshun (Jun 13, 2006)

dandurston said:


> The problem is your Hayes MX-1's. I spend maybe 30 seconds every couple weeks moving my pads in a click and I can easily 1 finger lock up my BB7's. I'm considering switching them to 6"'ers (from 8") because I don't need the power. I could be wrong about the whole 'leverage ratio' concept but I don't think there's a significant difference in the actual ratio here. The difference in power between mechs and hydro's comes from some of your power being absorbed by cable stretch with mechs whereas hydro's use uncompressable fluid so 100% of your power is transfered compared to 90-95%. The rotor diameter seems to be a much bigger factor than whether it's a mech or a hydro in terms of potential stopping power.


I don't think it's an issue with my calipers, they both function quite well, and the rear was a new replacement when I bought the bike. I have no problem locking up the wheels, I can even balance on the front a little, though I am not that good at it...

This is the dh/fr forum, and to say mechanicals are 95 good as hydros could cause someone seeking info to seriously hurt themselves on that advice:nono: . I have been lucky not to smash into a tree on the several occasions my mechanical brakes have had sudden and intense heat failure. This is not a matter of Avid/Hayes it's a matter of force applied by LEVERAGE

a set of 2004 HFX 9's using a single piston caliper on 6" rotors rest on my GFs ride, and it's incredible the difference in power and reliability. they have been bled twice, once each season since purchase, no failures and need attention 1/10th as often as mechanicals


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## dandurston (Jan 20, 2005)

mtb_biker said:


> hydro's offer a mechanical advantage that cable's just can not compete with.


...and what would that be? Hydro's transfer 100% of the power you apply to the lever to the pads whereas mechs lose about 5% along the way due to cable stretch. It's not some complicated or magical thing. If it was just about leverage ratio's then it would be a super easy fix. In terms of all out stopping power it really just comes down to the grip the pads have on the rotor. If the pads grip well then you won't need to apply a lot of force to lock up the wheel but if they don't grip well then you gotta work a whole lot harder (try locking a rotor with oil on it with any braking system). If you had two brakes that were identical in every way except one was a hydro and one was a mech then they'd perform identically except you'd have to pull a tiny bit harder (ie. 5%) with the mech to make up for the cable stretch.


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## Zonk0u (Jun 3, 2004)

dbabuser said:


> A pound added to or subtracted from the bike *would* mean less if it was attached to your torso. Instead, it's out at the ends of your appendages, which gives it a bit of leverage. On top of that, any rotational mass has to both stop and start a bit on every corner. Add up these effects at the bottom of a race run when you can barely breathe, and THAT is why the pros are worrying about how much their bikes weigh.
> For the rest of us, it all depends on how serious you are. If you're a 300 lb'er doing cruiser runs down the mountain, then no, it's most likely not worth it for the performance advantage. Don't think just because you can't tell and it's not important to you that it shouldn't matter to anybody.


you're talking in minute grams... not pounds. removing a gram from your wheelset is completely irrelevant.


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## BikeSATORI (Mar 20, 2004)

dandurston said:


> ...and what would that be? Hydro's transfer 100% of the power you apply to the lever to the pads whereas mechs lose about 5% along the way due to cable stretch. It's not some complicated or magical thing. If it was just about leverage ratio's then it would be a super easy fix. In terms of all out stopping power it really just comes down to the grip the pads have on the rotor. If the pads grip well then you won't need to apply a lot of force to lock up the wheel but if they don't grip well then you gotta work a whole lot harder (try locking a rotor with oil on it with any braking system). If you had two brakes that were identical in every way except one was a hydro and one was a mech then they'd perform identically except you'd have to pull a tiny bit harder (ie. 5%) with the mech to make up for the cable stretch.


where did you get the 5% from?
I'd agree with the point of lock-up idea... but I don't think that's what it is all about... but indeed is one possible advantage to running a 6" on the rear. don't have to fight as much for modulation and resist unintentional lock-up (not that this is necessarily a hard skill to attain, but ease is what it's all about)


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## mtb_biker (Jan 27, 2004)

dandurston said:


> ...and what would that be? Hydro's transfer 100% of the power you apply to the lever to the pads whereas mechs lose about 5% along the way due to cable stretch. It's not some complicated or magical thing. If it was just about leverage ratio's then it would be a super easy fix. In terms of all out stopping power it really just comes down to the grip the pads have on the rotor. If the pads grip well then you won't need to apply a lot of force to lock up the wheel but if they don't grip well then you gotta work a whole lot harder (try locking a rotor with oil on it with any braking system). If you had two brakes that were identical in every way except one was a hydro and one was a mech then they'd perform identically except you'd have to pull a tiny bit harder (ie. 5%) with the mech to make up for the cable stretch.


Not true. Hydro cables do flex and do not transfer 100% of the power you apply at the lever directly to the pads. Where are you getting these magical numbers from? I'm talking about Hydraulic Leverage ratio's as the benefit.


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## Karupshun (Jun 13, 2006)

dbl post


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## Karupshun (Jun 13, 2006)

mtb_biker said:


> Not true... Where are you getting these magical numbers from? .


from the offical beureau of pulling-numbers-out-of-your-ass


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## XSL_WiLL (Nov 2, 2004)

Karupshun said:


> I don't think it's an issue with my calipers, they both function quite well, and the rear was a new replacement when I bought the bike. I have no problem locking up the wheels, I can even balance on the front a little, though I am not that good at it...
> 
> This is the dh/fr forum, and to say mechanicals are 95 good as hydros could cause someone seeking info to seriously hurt themselves on that advice:nono: . I have been lucky not to smash into a tree on the several occasions my mechanical brakes have had sudden and intense heat failure. This is not a matter of Avid/Hayes it's a matter of force applied by LEVERAGE
> 
> a set of 2004 HFX 9's using a single piston caliper on 6" rotors rest on my GFs ride, and it's incredible the difference in power and reliability. they have been bled twice, once each season since purchase, no failures and need attention 1/10th as often as mechanicals


HFX-9s are opposing two pistons. I find that in the long run, when you're really riding hard, the Nines are more prone to failure. I've had much better luck with the Mags.


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## cranberry (Nov 15, 2005)

.....


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## Freerydejunky (Sep 21, 2006)

XSL_WiLL said:


> HFX-9s are opposing two pistons. I find that in the long run, when you're really riding hard, the Nines are more prone to failure. I've had much better luck with the Mags.


I plan on runing my hayes9 till they break. They arnt the best but they work. Im either going to go mags or maybe juicy 7's? The 9's are really good for XC from my experiance.


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## cranberry (Nov 15, 2005)

I tell my wife I have 8" up front but she swears it's only 6" :madman:


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## dbabuser (Jan 5, 2004)

Karupshun said:


> This is the dh/fr forum, and to say mechanicals are 95 good as hydros could cause someone seeking info to seriously hurt themselves on that advice:nono: . I have been lucky not to smash into a tree on the several occasions my mechanical brakes have had sudden and intense heat failure. This is not a matter of Avid/Hayes it's a matter of force applied by LEVERAGE


You've obviously never ridden Avid mechical discs. Don't take the word of the dh/fr board - most of them have not tried the Avids and just assume hydro's are better. Check out the FAQ in the brake forum for more unbiased opinions. And mechs are dangerous for dh? I guess I'm lucky I survived a season of racing dh in the rockies with them...  I'd take them over Hayes any day.


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## dbabuser (Jan 5, 2004)

*What?*



Zonk0u said:


> you're talking in minute grams... not pounds. removing a gram from your wheelset is completely irrelevant.


Reread my post - I said a pound would make a difference. Where did you see the word gram?


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## BikeSATORI (Mar 20, 2004)

dbabuser said:


> Don't take the word of the dh/fr board - most of them have not tried the Avids and just assume hydro's are better.


I like how you come here and label the ENTIRE dh/fr forum population based on your ONE opinion.... so we are now stereotyped as unbelievable, huh? Coming from a person labeling so many people, I can no longer believe anything coming from your posts, they are so saturated with opinion... And infact, I do have BB7's.


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## BikeSATORI (Mar 20, 2004)

cranberry said:


> I tell my wife I have 8" up front but she swears it's only 6" :madman:


ouch!

man, did you try that adapter she suggested to you? at least there's no hydraulic lock!

hahhaha...


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## Karupshun (Jun 13, 2006)

XSL_WiLL said:


> HFX-9s are opposing two pistons. I find that in the long run, when you're really riding hard, the Nines are more prone to failure. I've had much better luck with the Mags.


really? the 2004s have two actuating pistons? that's cool. 
I thought they was only single piston actually moving with the way her disc was always deflecting when under breaking.

I don't have a manual for them, nor can I find any decent info on the 03/04 calipers


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## Karupshun (Jun 13, 2006)

dbabuser said:


> You've obviously never ridden Avid mechical discs. Don't take the word of the dh/fr board - most of them have not tried the Avids and just assume hydro's are better. Check out the FAQ in the brake forum for more unbiased opinions. And mechs are dangerous for dh? I guess I'm lucky I survived a season of racing dh in the rockies with them...  I'd take them over Hayes any day.


No, I haven't really ridden enough avid mechs to gauge a real opinion. If you decided to actually read any of my previous posts, you'll see that my point wasn't about comparing avid vs hayes, It was about how fast mechanicals fade.

Hydros are better isn't an assumption. It is simply a fact Juicy 3's inspire more confidence...common sense, and the laws of hydraulic pressure differences tell me that no matter how awesome you think your bb7s are, it is simply wishful thinking.

and I will say it again. MECHANICAL DISC BRAKES SHOULD NOT BE USED FOR DH
this is not a DH/FR forum conspiricy, and no one is going to stop you from running your mechs if you want to 'compete'


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## hab1b (Jan 15, 2007)

i just rode today with a 6 inch rotor on the rear. wow what a difference. i love it so much more control over your wheel thatn with an 8 inch.. im glad i made the switch.


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## XSL_WiLL (Nov 2, 2004)

Karupshun said:


> really? the 2004s have two actuating pistons? that's cool.
> I thought they was only single piston actually moving with the way her disc was always deflecting when under breaking.
> 
> I don't have a manual for them, nor can I find any decent info on the 03/04 calipers


Only the So1es are one piston.

If only one piston is moving, hooray, you have a sticky piston! Or a bleed issue.


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## Karupshun (Jun 13, 2006)

XSL_WiLL said:


> Only the So1es are one piston.
> 
> If only one piston is moving, hooray, you have a sticky piston! Or a bleed issue.


fudge:

oh well, it happens. Just another thing for the wrench to service in the spring


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## euroford (Sep 10, 2006)

mtb_biker said:


> Not true. Hydro cables do flex and do not transfer 100% of the power you apply at the lever directly to the pads. Where are you getting these magical numbers from? I'm talking about Hydraulic Leverage ratio's as the benefit.


OMG.... basicly principals of hydralics. its a force multiplyer. its transmits way MORE than 100% of the lever force to the pads.

have you maybe ever operated a hyrdolic car jack? did you need to press down on the lever with 4000lbs?

thanks wiki: http://en.wikipedia.org/wiki/Hydraulic_machinery


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## mtb_biker (Jan 27, 2004)

euroford said:


> OMG.... basicly principals of hydralics. its a force multiplyer. its transmits way MORE than 100% of the lever force to the pads.
> 
> have you maybe ever operated a hyrdolic car jack? did you need to press down on the lever with 4000lbs?
> 
> thanks wiki: http://en.wikipedia.org/wiki/Hydraulic_machinery


That's exactly what i'm saying. He is saying that hydro cables do not flex at all hence the comment about the 100%. Go back and read what i said before that. You've mis-interpreted what i wrote.


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## Karupshun (Jun 13, 2006)

euroford said:


> OMG.... basicly principals of hydralics. its a force multiplyer. its transmits way MORE than 100% of the lever force to the pads.
> 
> have you maybe ever operated a hyrdolic car jack? did you need to press down on the lever with 4000lbs?
> 
> thanks wiki: http://en.wikipedia.org/wiki/Hydraulic_machinery


he's not implying that you get only a 1 to 1 ratio from the brake booster. originally it was stated that hydro transfers 100% of the braking force generated in the lever through hydraulic compression to the caliper, while mechanical brakes transfer 95% and lose 5% through cable stretch

I think everyone can agree that through the laws of hydraulics, cramming fluid from a big chamber into a small one causes incredible amounts of pressure to be exerted

those that wish to argue further:
http://www.theflatearthsociety.org/forums/


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## dbabuser (Jan 5, 2004)

Karupshun said:


> No, I haven't really ridden enough avid mechs to gauge a real opinion. If you decided to actually read any of my previous posts, you'll see that my point wasn't about comparing avid vs hayes, It was about how fast mechanicals fade.
> 
> Hydros are better isn't an assumption. It is simply a fact Juicy 3's inspire more confidence...common sense, and the laws of hydraulic pressure differences tell me that no matter how awesome you think your bb7s are, it is simply wishful thinking.
> 
> and I will say it again. MECHANICAL DISC BRAKES SHOULD NOT BE USED FOR DH


And maybe you did not read my post, or take my advice and do a little more research before you posted more erroneous "facts" again. I ran avid BB7s for a season of dh racing in the Mountain States Cup. I am 185lbs with no gear, and I didn't experience any fade or loss of power. I was running 8" front, 7" rear rotors.
Wishful thinking? I also have a set of Juicy 7's, and while they do feel a bit smoother at the lever, I don't think they are any more powerful than the BB7s. I've also dh tested Hayes Mags, Hope Mono 6ti's and Magura Gustavs. The Hopes and Gustavs are a bit more powerful, but not enough to make them worth the money, IMO. The Hayes were not at all impressive, and I wouldn't ever consider them an option.


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## dante (Jan 12, 2004)

late to the argument, but I've tried almost every type of cable disc with all sorts of teflon cables and compressionless housing, and they still can't hold a candle to a good set of hydraulics. in terms of power and modulation, BB7s are a definitive step below HFX-9/Mags, and that's nowhere near the Juicy 7, Shimano XT/Saint, Codes, Gustavs, Hopes, etc. BB7s with good cables/housing were an acceptable substitute 5-7 years ago when Hydros weren't very good, but now there really is no question.


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## Karupshun (Jun 13, 2006)

dbabuser said:


> And maybe you did not read my post, or take my advice and do a little more research before you posted more erroneous "facts" again. I ran avid BB7s for a season of dh racing in the Mountain States Cup. I am 185lbs with no gear, and I didn't experience any fade or loss of power. I was running 8" front, 7" rear rotors.
> Wishful thinking? I also have a set of Juicy 7's, and while they do feel a bit smoother at the lever, I don't think they are any more powerful than the BB7s. I've also dh tested Hayes Mags, Hope Mono 6ti's and Magura Gustavs. The Hopes and Gustavs are a bit more powerful, but not enough to make them worth the money, IMO. The Hayes were not at all impressive, and I wouldn't ever consider them an option.


good friggin god, talk about not reading posts. the whole argument is based on riders weighing over TWO-HUNDRED pounds. 


solarburn said:


> I weigh 220 and have as much power as any hydros I've used minus Gustav's.





karupshun said:


> granted I use Hayes MX-1s but I am your size. I run them on 8" Saint discs with kool-stop semi metallic pads.


I ride a Banshee Chaparral XL, and have it spec'd out on the burly side of the block. If you weren't so pretentious, you'd find that nowhere am I taking issue with the preformance of the BB7, nor Avid, as on the *first* page plainly shows. I carry a goddamn hell of a lot more momentum into a corner than you do. You can preach how YOU can stop with bombin down a race-run, and how you've tried *everything* and only the most precison german-engineering can compare is a load of bull.

dressed for a long day I bet with my bike i'm at least 275. and looking to mechanical brakes of ANY kind is utterly stupid


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## roaddog (Aug 30, 2004)

My dirt jump has cable discs with an 8" in front and 6" in the rear. My dh bike has 8" front and rear. My thought is that an 8" isn't needed on the rear of the dirt jump because of the amount of braking done on that bike vs the dh bike. the dirt jump is on and off braking while the dh bike can see alot more braking. So I am thinking surface area for heat dissapation. Not much is needed on the rear of my dirt jump bike since the front does more braking. I don't know about bike brakes, but some automotive brakes work best when warmed up a bit.


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## XSL_WiLL (Nov 2, 2004)

dante said:


> late to the argument, but I've tried almost every type of cable disc with all sorts of teflon cables and compressionless housing, and they still can't hold a candle to a good set of hydraulics. in terms of power and modulation, BB7s are a definitive step below HFX-9/Mags, and that's nowhere near the Juicy 7, Shimano XT/Saint, Codes, Gustavs, Hopes, etc. BB7s with good cables/housing were an acceptable substitute 5-7 years ago when Hydros weren't very good, but now there really is no question.


HFX-9s have practically NO modulation. The amount of modulation from the BB7s can be adjusted by the position of the static pad.


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## shopvet (Oct 10, 2005)

euroford said:


> i initially ran 8" f & r, but the frame clearance on the 8" rotor was rather slim. so i tried out a 6" rotor in the rear and found that not only did it have more than enough power, but that it was easier to modulate and avoid lockup.


This is why i run a smaller disc on the rear - better modulation. No matter what, a sliding wheel is slowing you down more than a rolling one, and doesn't have as much control. Motos (on AND off-road) have been using smaller/less powerful rear brakes for decades. It takes a much smaller force to lock up the rear wheel, so a smaller brake is all that's called for.

Try it out before tossing out the idea - you may find it'll make you faster!


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## dandurston (Jan 20, 2005)

dbl post..see page 4


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## dandurston (Jan 20, 2005)

euroford said:


> OMG.... basicly principals of hydralics. its a force multiplyer. its transmits way MORE than 100% of the lever force to the pads.have you maybe ever operated a hyrdolic car jack? did you need to press down on the lever with 4000lbs?


Leverage isn't something that's exclusive to hydraulics. You make it sound like hydraulics are some magical thing that have the sole rights to using leverage. Yes a hydraulic car jack can lift 4000lbs when you press down with way less force, but so can a mechanical jack (ever had a flat tire?). It's not because of the miracles of hydraulics...it's because of the leverage ratio. That's why you press the jack handle down 3 feet and the car only goes up half an inch. The same is true with brakes...you pull the brake lever maybe an inch and then the brake pads move maybe 1/8" so you get about 8x the power (800%). Both mechancial and hydraulic brakes use leverage so the pads are squeezing many times harder than you're pulling on the lever. This idea of mulitplying the force is a pretty basic one and it's true for not only mechanical and hydraulic disc brakes but also for everything from bolt cutters to pliers. 
*The leverage ratio for a set of brakes has nothing to do with whether it's a hydraulic or mechanical system.* Hydraulics are just one of many possible means of transferring the power from your lever to the caliper. They are a particularly good means because they are very efficient so about 99% of the power makes it to the caliper whereas mechanical cables are less efficient due to cable stretch and housing friction so you end up only transferring closer to 90% of the power.

Consider Shimano vs. SRAM rear derailleur shifting...SRAM uses a 1:1 ratio where as Shimano uses a 2:1 ratio yet both are mechanical systems. SRAM shifters are way easier to push because for every bit you push the lever you are only moving the derailluer half as far. The result is that you have to push the lever twice as far but it's twice as easy to push it (assuming equal spring rates for the rear derailleur). My point is that it's relatively simple to engineer any set of brakes (mech or hydro) with withever leverage ratio the engineers desire. Multiplying the force is a basic principle of leverage, not "a basic principle of hydraulics".

The purpose of the hydraulic fluid or the mechanical cables is just to transfer to the power you apply at the lever, back to the caliper. The goal is to do this as efficiently as possible so that you aren't wasting your pulling efforts. It's a widely accepted fact that hydraulics are more efficient but it's not like it's a night and day difference....it's about 5%.

A much bigger factor in the mech vs hydro debate is that the biking industry views hydro's as being superior (and they are) so they use hydraulics for all the high end brakes...but that's not the main reason why these brakes so powerful. When Magura set out to design the Gustav they used a hydro system because hydro's are more efficient but a much bigger reason why the Gustav's have gobs of stopping power is because they use very good pads and have a slew of pistons so they have incredible grip on the rotor. If Magura sold a cable version of the Gustav that was identical in every way except it used cables then it would still be about 95% as powerful as current Gustav.

Anyways, with all that said...I just bought some hydros (see link below). I agree that hydro's should be used on a XC rig where weight is important or on a DH rig where all out stopping power is very important but I think there's a certain group of riders in the 'freeride' segment can't afford to replace a $100 lever whenever they crash and so for them mechs make a lot of sense because 8" BB7's offer a lot of stopping power at a very affordable price and they are very easy to setup and maintain.

I think I'm going to give these a shot with an 8" rotor up front and 6" in the back to save a bit of weight. These aren't the best brakes but they were fairly cheap and they're super light. With an 8" up front they may work fine and if not..I should be able to sell em for about what I paid.
http://cgi.ebay.com/ws/eBayISAPI.dl...MEWA:IT&viewitem=&item=200074617617&rd=1&rd=1


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## hab1b (Jan 15, 2007)

i have those on my hardtail. to be honest i like em a lot.


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## solarburn (Jun 27, 2005)

Karupshun said:


> I really have to disagree. I find myself spending an amazing amount of time working on my mechanical brakes to maintain any sort of acceptable stopping power. especially on the trail tunging the fine-adjusts all the time. Good hydros need to be bled once a year if done correctly.
> 
> granted I use Hayes MX-1s but I am your size. I run them on 8" Saint discs with kool-stop semi metallic pads. The brake fade on the organic pads & stock hayes rotors were a joke on any sort of long decent regardless of grade.
> 
> saying bb7s are as good as any hydro other brake beside the Gustav is naieve The force applied through hydraulic pressure from the brake booster to the piston is many times greater than the leverage ratio granted on even the best mechanical levers. Maybe your gigantic man-hand has the power to never fatigue and one-finger it, but mine are normal human-hands that get tired. I think you need to find some long, tight, fast, and technical single track and take a new look at hydros


Oh hellls no. I ride all kinds of singletrack here in Washington especially tight windy up down and long declines. My brakes are set up to have exceptionally easy pull. I make minor adjustments only while riding but power and modulation are always fine. Brake pad changes are easy and on par with any other disc brake as far as durability.

They worked great at Whistler this summer although my forearms were wasted after the day of riding. So were my buds from their hydros. Brake fade was not an issue. My Hayes Mags power and modulation were not as good(sold that bike). My Gustav outshines them though. Half finger pull lol. Did I forget to mention I use hydros too? My bad.

BB7's are competetive with hydros in performance and especially cost and ease of maintenance. I did suffer performance loss on the rear after 3 yrs using them. Pad changes didn't do it. Put on a new disc and bang it was back. The wavey discs Avids uses now are shiat. I just put new BB7s on one bike and the wavey discs ruined performance. I replaced with Hayes disc cause cheaper then the Clean Sweeps and bang performance was there.

Bad pads, shotty discs, and bad routing of cable can mess up any set up. Make ya think Mechs suck even. I can work shiat out though. I will admit there is nothing easier to pull than a good hydro, especially one that has no fade. My set up is very usable and really close to that kind of pull and power.


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## solarburn (Jun 27, 2005)

XSL_WiLL said:


> HFX-9s have practically NO modulation. The amount of modulation from the BB7s can be adjusted by the position of the static pad.


Not to mention continual brake rub. BB7's are a better performer than these.


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## dandurston (Jan 20, 2005)

The Hayes HFX 9's? According to the MTBR reviews they seem a little high maintenance but when they're dialed they're supposed to work good.

My issue now is that I wanna run 8" up front and 6" in the rear but these brakes comes with 6" rotors and my BB7's are 8" rotors and I hate to mix and match. I'm going to need to find someone with one of these brakes and trade a 8 for a 6 or a 6 for an 8.


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## hab1b (Jan 15, 2007)

rotors are fairly cheap... and yes i love the hayey HFX 9. They were a pain t get dialed but once i did they were awesome. right now im running mags and they are nice but somthing bout my nines that i miss.


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## JSUN (Jun 22, 2004)

hab1b said:


> rotors are fairly cheap... and yes i love the hayey HFX 9. They were a pain t get dialed but once i did they were awesome. right now im running mags and they are nice but somthing bout my nines that i miss.


are the levers different? dont the nines have a sort of rounded feel, where the mags are somewhat square?


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## BikeSATORI (Mar 20, 2004)

JSUN said:


> are the levers different? dont the nines have a sort of rounded feel, where the mags are somewhat square?


other way around... mags are rounded, 9's are squarish with like ridges... that's the only differences between the two, is the levers I believe...


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## dandurston (Jan 20, 2005)

BikeSATORI said:


> other way around... mags are rounded, 9's are squarish with like ridges... that's the only differences between the two, is the levers I believe...


There's gotta be more to it than that. The Mags are an extra $40-$50/wheel. Other than the colour they do look pretty similar though.


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## dbabuser (Jan 5, 2004)

Karupshun said:


> good friggin god, talk about not reading posts. the whole argument is based on riders weighing over TWO-HUNDRED pounds.


You're funny - I think you're not even reading your own posts now.
What about this statement?
_and I will say it again. MECHANICAL DISC BRAKES SHOULD NOT BE USED FOR DH_


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## BikeSATORI (Mar 20, 2004)

dandurston said:


> There's gotta be more to it than that. The Mags are an extra $40-$50/wheel. Other than the colour they do look pretty similar though.


don't quote me on it, but yeah, as far as I know, they both use the Generation 2 caliper and same hose... so, it's just down to a different lever body/master cylinder.
I'm not a big fan of either, the mags are trusty, solid brakes, but not my fav. by any means... I'm a Hope Mono man myself, be it M4 or mini...


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## dandurston (Jan 20, 2005)

I'm a fan of the Hope Mono's too but I'm not a big fan of the price. I'd be suicidal if I wrecked one of those in a crash.


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## Karupshun (Jun 13, 2006)

dbabuser said:


> You're funny - I think you're not even reading your own posts now.
> What about this statement?
> _and I will say it again. MECHANICAL DISC BRAKES SHOULD NOT BE USED FOR DH_


...Sigh ...

I'll say it again and again too because it's an industry standard for a reason
This is an amazing show of how you can hold up an asinine argument with nothing more than opinion... Good show .

In a race application, -- those riding for Team Bro-Kass -- mechanical brakes will function adaquately for racers of the right size. The whole idea is to stay off them anyways

In a day-to-day application of park-riding it is irresponsible to reccomend mechanical brakes. If they indeed were truly adaquate, we would see manufacturers speccing out more DH/FR oriented bikes with mechanical brakes, no?

or is this a conspiricy to more expensive bike components

If you want to continue trying to troll, go ahead, you've already shown to just about everyone whoe had the joy of reading this thread that you're just a blowhard good luck being taken seriously


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## fsrxc (Jan 31, 2004)

XSL_WiLL said:


> Only the So1es are one piston.
> 
> If only one piston is moving, hooray, you have a sticky piston! Or a bleed issue.


Or the caliper may not be centered on the rotor...


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## solarburn (Jun 27, 2005)

Karupshun said:


> ...Sigh ...
> 
> I'll say it again and again too because it's an industry standard for a reason
> This is an amazing show of how you can hold up an asinine argument with nothing more than opinion... Good show .
> ...


I just noted you used Kool Stop pads on your mechs. Man I tried these out and had the same thing happen to me out on a ride where it was crucial to not have fade(lots of downhill stretches). The fade was so bad it was scary. I switched them out straight away. Very unsafe especially at our weights. Ruines the flow.

Be cool man. The contempt was a bit thick. I can't add you to my Buddy list if you Bully around like that he he.


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## dandurston (Jan 20, 2005)

Karupshun said:


> In a day-to-day application of park-riding it is irresponsible to reccomend mechanical brakes. If they indeed were truly adaquate, we would see manufacturers speccing out more DH/FR oriented bikes with mechanical brakes, no?


Hydro's are better brakes and so when a company designs some new high end DH/FR brakes they use hydro's so that the brakes are consistantly good...it's silly to use an inferior means of power transfer (mechs) when you're designing a 6 piston brake with carbon fibre levers....you want to make all the aspects of the brake top notch.

As a result, even though someone could make amazing 6 piston mechs they don't because they wouldn't be quite as amazing as 6 piston hydros. The point is that mechs do not appear on many high end bikes because high end bikes use high end components and there are very few high end mech brakes. Avid's BB7's are the most 'high end' mech brakes that I'm aware of.

To answer your question, I think you are being a little close minded when you say recommending mechs is irresponsible. Mechs are more simple and reliable than hydros. If there's a brake that's going to suddenly fail you, it isn't going to be a BB7.

Furthermore, 8" BB7's are more powerful than any 6" hydro that I'm aware and probably more powerful than most 7" hydro's as well. According to Hayes's website, a 7" brake is about 35% more powerful than a 6" brake and so even if mechs are only 90% as a hydro, an 8" BB7 is still going to at least hold it's own against a 7" hydro.

So I guess I don't understand why you say recommending them is irresponsible. They are at least as reliable and tons of guys rock the park with 7" brakes or less so the power is there if you're using 8" mechs. I don't see what I'm missing here....

We don't see more manufacturers spec'ing out DH/FR bikes with mechs because no one puts low end components on a high end bike but mechs can still do the job which is why you do see them on some lower end DH/FR bikes for example:

- 2007 Kona Shred (billed on KonaWorld.com as a DJ/FR bike)
- 2006 Rocky Mtn. Flow (rated for Bike Park/Freeride on RM site)
- 2007 Specialized P.1

Anyways, I don't have time to research all the bikes that use mechs but the point is, they are a viable option for park riders on a budget. Going with a 8" Mech over a 7" Hydro may add some weight to your rig and maybe a smidge more fatigue to your fingers but it seems rather elitist to say that riders without hydro's shouldn't be in the park.


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## Karupshun (Jun 13, 2006)

solarburn said:


> I just noted you used Kool Stop pads on your mechs. Man I tried these out and had the same thing happen to me out on a ride where it was crucial to not have fade(lots of downhill stretches). The fade was so bad it was scary. I switched them out straight away. Very unsafe especially at our weights. Ruines the flow.
> 
> Be cool man. The contempt was a bit thick. I can't add you to my Buddy list if you Bully around like that he he.


what can I say, I like serving sarcasm by the slice but yes, this whole conversation has gotten out of control. I think we can just agree to disagree, eh debabuser?

Ya, I burned up two sets of Jagwire pads before I tried the kools. They've worked the best so far, I've consumed too many pads too quickly, but getting a set of real hayes issue pads are 75 bucks a set at my lbs.

I'm really hoping the codes work well for me. the lever is tough enough, and has a cool break-away feature to help during crashes.


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## LarryFahn (Jul 19, 2005)

dbabuser said:


> A pound added to or subtracted from the bike *would* mean less if it was attached to your torso. Instead, it's out at the ends of your appendages, which gives it a bit of leverage. On top of that, any rotational mass has to both stop and start a bit on every corner. Add up these effects at the bottom of a race run when you can barely breathe, and THAT is why the pros are worrying about how much their bikes weigh.
> For the rest of us, it all depends on how serious you are. If you're a 300 lb'er doing cruiser runs down the mountain, then no, it's most likely not worth it for the performance advantage. Don't think just because you can't tell and it's not important to you that it shouldn't matter to anybody.


Actually, I'm not a "cruiser" or a "300 lb'er". I'm 255lbs. my bike is 55 and my Camelback and knee/shin guards are prolly around 15. I only do a handful of races per year. I ride Creek or Platty every weekend. If you think the east doesn't compare to the Rockies, come ride with us. When you're riding a fall line on loose shale and have to brake for a 90* turn to a 6 foot drop and a right turn 15' away in between trees... My brakes do make a difference.

Anyway, Your arguement is getting beaten down by 10-15 people. I think the majority wins this arguement. Fahn

ps, Can't forget that I RIDE WHITEFACE too!


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## Rover Nick (Jul 13, 2006)

LarryFahn said:


> Actually, I'm not a "cruiser" or a "300 lb'er". I'm 255lbs. my bike is 55 and my Camelback and knee/shin guards are prolly around 15. I only do a handful of races per year. I ride Creek or Platty every weekend. If you think the east doesn't compare to the Rockies, come ride with us. When you're riding a fall line on loose shale and have to brake for a 90* turn to a 6 foot drop and a right turn 15' away in between trees... My brakes do make a difference.
> 
> Anyway, Your arguement is getting beaten down by 10-15 people. I think the majority wins this arguement. Fahn
> 
> ps, Can't forget that I RIDE WHITEFACE too!


What does where you ride have anything to do with weight? Are you 255 with the bike or without?


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## Rover Nick (Jul 13, 2006)

LarryFahn said:


> . It's a DH bike. A pound doesn't mean anything when you weigh more than the bike. Argue as much as you want, but grams aren't even noticeable.


Grams aren't noticable, but pounds are. They are especially noticeable with something as light as a bike. My bike is 40lbs. So that means that a pound is roughly 2.5% of my bikes total weight. I would think that is noticeable for someone who is paying attention. Especially if that is multiplied by being rotating mass. If we were talking dirtbikes or especially cars then no, a pound would not be noticeable. Also, you say you are 300lbs(with gear and bike, im assuming) while I'm 190lbs with bike and gear, so I would probably notice more than you. And it sounds like you just don't care about weight which is fine but don't tell me what I can notice and what I can't.

And your excuse of "its a DH bike" is really lame. Any thing that weighs more will take longer to accelerate, longer to slow down, and longer to turn. You can try to argue the laws of physics, but you won't win that one.


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## XSL_WiLL (Nov 2, 2004)

fsrxc said:


> Or the caliper may not be centered on the rotor...


Even if the caliper is not centered, both pistons should move. And he said that one piston is pushing the rotor and causing it to deflect into the other pad. While it does have a dominant piston, it should not be to that extent.


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## XSL_WiLL (Nov 2, 2004)

BikeSATORI said:


> don't quote me on it, but yeah, as far as I know, they both use the Generation 2 caliper and same hose... so, it's just down to a different lever body/master cylinder.
> I'm not a big fan of either, the mags are trusty, solid brakes, but not my fav. by any means... I'm a Hope Mono man myself, be it M4 or mini...


The Nine HD is kind of rounded as well. The HD and the regular Nine are both the same, just the lever casting varies slightly.

The Mags and Nine differ in both the lever casting and the MC. The Nine uses a hard MC while the Mag has sort of a "soft" MC.

The modulation and durability of the Mags are siginificantly improved (IMO).


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## Whitebread (Aug 28, 2006)

shopvet said:


> This is why i run a smaller disc on the rear - better modulation. No matter what, a sliding wheel is slowing you down more than a rolling one, and doesn't have as much control. Motos (on AND off-road) have been using smaller/less powerful rear brakes for decades. It takes a much smaller force to lock up the rear wheel, so a smaller brake is all that's called for.
> 
> Try it out before tossing out the idea - you may find it'll make you faster!


Sliding friction is less than static friction for any given rolling object. The only way a sliding tire would slow you down faster is if trail material gathered infront of the tire. The problem wiht that is a sliding tire cannot provide you with any sttering capabilities, it will go wherever it pleases.

You never, ever, want to lock up any wheel on your bike, car, etc unless you are trying to induce a skid on purpose. Braking on the threshold of static friction is where its at.


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## Freerydejunky (Sep 21, 2006)

Whitebread said:


> Sliding friction is less than static friction for any given rolling object. The only way a sliding tire would slow you down faster is if trail material gathered infront of the tire. The problem wiht that is a sliding tire cannot provide you with any sttering capabilities, it will go wherever it pleases.
> 
> You never, ever, want to lock up any wheel on your bike, car, etc unless you are trying to induce a skid on purpose. Braking on the threshold of static friction is where its at.


so ur telln me that all the pros that lock up the rear tire for some turns are wrong and they have no control?


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## LWright (Jan 29, 2006)

"No matter what, a sliding wheel is slowing you down more than a rolling one,"
ummm, no,
probably just a missing "not"


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## Ojai Bicyclist (Nov 4, 2005)

Drifting does not equal skidding.


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## Whitebread (Aug 28, 2006)

All this debate of power, power, power is completely USELESS. What you guys don't realize is that locking up a wheel is completely useless to the rider in question. Its been agreed that both mechanical and hydraulic brakes can lock up the wheels at high speed. The characteristic that will seperate mechanical from hydraulic is feel, modulation and reaction time, THATS IT! 
Reaction time:
Hydraulic's will have a higher reaction time. With mechanicals, you must take up any slack (no matter how small) in the lines, calipers and levers before the pads contact the rotor. With a properly setup hyrdaulic, the system will always have fluid in teh caliper resting against the piston. The only limiting factor is how fast the fluid reacts to the pressure gradient created by the squeezed lever. 
Feel and modulation: Hydraulics win here as well. The fluid can "transmit" force in both directions meaning that the level can push on the piston and the piston can push on the lever. The rider can feel what is happening as the pad is pushing against the rotor with more percision than mechanicals can. In order to really see this in action, just look to car brakes. Its not uncommon for the average driver to feel as little as .0004" of run out or surface variation in the rotor when braking under normal load. Mechanicals just can't match that. Furthermore, fluids never suffer from plastic deformations, they do compress and change volume in the same way that a metal wire will stretch under load, but they don't suffer from fatigue. And though the fluid will change volume at different temps, you can adjust that with the small pad position adjustment knobs and you set! Fixing a stretched/broken wire requires you to take the whole system apart. With fluid, you just drain, refil and rebleed.

The advantages that hyrdaulics carry out weigh its shortcommings (boiling temp of fluid, hydroscopic properties, complexiticy and cost). I'd rather have the hydros for aformentioned reasons.

Heed what I've said and stop wiht the foolish arguements about power. Wheel lockup does not a good brake make.


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## Ojai Bicyclist (Nov 4, 2005)

LWright said:


> "No matter what, a sliding wheel is slowing you down more than a rolling one,"
> ummm, no,
> probably just a missing "not"


You're mis-reading.


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## Whitebread (Aug 28, 2006)

motormonkeyr6 said:


> so ur telln me that all the pros that lock up the rear tire for some turns are wrong and they have no control?


I should have rephrased, its not a absolute. You just have more control over where the wheel goes if you don't lock it up.


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## Whitebread (Aug 28, 2006)

Ojai Bicyclist said:


> Drifting does not equal skidding.


Yes it does, its just a controlled skid. But take note from the autoracing industry, its not the fastest way to get through a corner. :thumbsup:


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## Ojai Bicyclist (Nov 4, 2005)

You don't use brakes to drift.

And yes, it's not always fastest, but it can be: just ask Sam Hill!


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## Whitebread (Aug 28, 2006)

Ojai Bicyclist said:


> You don't use brakes to drift.
> 
> And yes, it's not always fastest, but it can be: just ask Sam Hill!


In order to drift, you have to induce a skid in some direction, usually the direction you actually want to point, this can be induced by the brakes, or by power input.

Please note that I am speaking from the point of view of an auto racer, I have far more experience in auto racing than bike racing, although the physics is exactly the same.


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## Ojai Bicyclist (Nov 4, 2005)

In DH I guess I'm just used to hearing drift associated with no brakes.

I feel you, but remember that rally cars drift all the time to carry speed around loose corners. That's probably closer in terms of technique to DH than pavement racing.


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## mrpercussive (Apr 4, 2006)

Whitebread said:


> In order to drift, you have to induce a skid in some direction, usually the direction you actually want to point, this can be induced by the brakes, or by power input.
> 
> Please note that I am speaking from the point of view of an auto racer, I have far more experience in auto racing than bike racing, although the physics is exactly the same.


i used to race autocross and did a lot of touge and drift too... And no, drifting is not skidding... 2 different concepts. And drifting can be the fastest way around a corner if done correctly, ask Tsuchiya...

It all really depends on conditions.


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## collaborator (Jun 26, 2004)

Whitebread said:


> In order to drift, you have to induce a skid in some direction, usually the direction you actually want to point, this can be induced by the brakes, or by power input.


Controlled skid? What the **** are you talking about. I would be fine if you said controlled oversteer but skid?



Whitebread said:


> Yes it does, its just a controlled skid. But take note from the autoracing industry, its not the fastest way to get through a corner.


I guess those rally guys have it really messed up then. BTW judging from what you have said so far, and the constant backtracking and "rephrasing" you either:
1. English isn't you're first language..
2. You suck at explaining things...

OR

3. The only racing experience you have is Gran Turismo...


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## Whitebread (Aug 28, 2006)

mrpercussive said:


> i used to race autocross and did a lot of touge and drift too... And no, drifting is not skidding... 2 different concepts. And drifting can be the fastest way around a corner if done correctly, ask Tsuchiya...
> 
> It all really depends on conditions.


When I say its the same, I mean that its a lack of traction.

I can only comment on the physics of a moving object, I don't know much about the techniques of bicycle racing so when I say that drifting is not the fastest way through the corner I didn't think to apply it to off road racing (duh!).

Haha


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## davec113 (May 31, 2006)

Whitebread said:


> Yes it does, its just a controlled skid. But take note from the autoracing industry, its not the fastest way to get through a corner. :thumbsup:


That depends on the surface, the car, and the corner.

Ever seen a rally race? :skep:


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## tacubaya (Jan 27, 2006)

Retarded thread.


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## Whitebread (Aug 28, 2006)

davec113 said:


> That depends on the surface, the car, and the corner.
> 
> Ever seen a rally race? :skep:


I was speaking from experiences on road courses, which I guess doesn't have much bearing on a mountain bike forum.....sorry.


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## Iranian-Mechanic (May 6, 2004)

Its been discussed for a million times here.
For better control .For feathering .For avoiding rotor crash .For skinny guys .


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## erol/frost (Jan 3, 2004)

Karupshun said:


> from the offical beureau of pulling-numbers-out-of-your-ass


Hahaha this made me crack up


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