# Does my Tire Pressure seem high??



## Bttocs (Jun 21, 2014)

I am running GEAX AKA 2.2" tires with tubes on my 29er and been riding in some rock gardens recently in New England. I have an Airborne Seeker hardtail. It seems anytime I run less than 40 psi in my rear tire my tire is flat the next day. I am 6'4" and 245lbs. I am using a standard tube and the flats seem to be pin holes in the outer surface of the tube, basically under the tread covered surface of the tire. I have checked the inside of the tire for anything sharp and did find a small piece of metal that caused one flat. All have been slow leaks that go flat overnight. My questions are:


1. does 40 psi sound a bit high ?? I see most riders on this forum running low 30's. I did buy a digital pressure gauge to make sure I was getting good readings and have checked it against other gauges (gas station pump gauges)


2. what is a pinch flat ?? and where on the tube do you get them?? I assume the tube gets pinched between the tire and rim and they are on the inside surface of the tube.




Thanks in advance for the info.


----------



## Surfdog93 (May 30, 2005)

40 psi is pretty high for that tire, IMO. I used to be 230 psi, but never ran more than 34 psi in rear.
Were your tubes OK on other terrain ? If so, then sounds like pinch flats / snake bites…yes, as you noted in 2. 

I would try going tubeless, assuming your wheels will permit.


----------



## Bttocs (Jun 21, 2014)

Thanks Surfdog,

Anyone else care to reply with what pressure you run in your tubed tires?? and what you weigh.

I googled pinch flats and now understand what they are. they are not what I thought they were. I am getting a single snake eye leak, not double leaks, but they are in the area of the tube where pinch flats happen. It is probably due to my lack of technique, but staying above 40 psi seems to eliminate it. The ride is a little bouncy at that pressure, but I guess for me, I will have to make changes to run lower pressures.


----------



## NYrr496 (Sep 10, 2008)

When I still ran tubes, I ran about 32 psi in my tires. Now, tubeless, I run about 28 in my front and 30 in the rear. 
This is a 2.3 in the front and a 2.2 in the rear on 30mm rims. 
How wide are your rims? I'm exactly your size, maybe a few pounds heavier and have no tire issues.


----------



## singletrackmack (Oct 18, 2012)

Not sure how wide your rims are, but a wider tire will allow you to run less PSI without pinch flats. I weigh just about the same as you and because of that weight I wouldn't run anything less than a 2.35" front or back. If your riding rocky terrain you would be well off to get wider tires and run a lower psi.

I use tubes and just put some 2.5" front and back on my AM bike and run it in the low 20psi range when out on the singletrack trails in North Lake Tahoe. Very rocky black diamond tech trails and have no issues with pinch flats. I couldn't imagine running 40psi on that chunk. Wheels would be bouncing and slipping all over the place.

2.5" tire might be pretty heavy though since your riding a 29er, but if your running big wheels anyways I assume rollover is the priority and weight isn't really a concern so you might as well get big tires to match the big wheels and the big rider


----------



## TaupoRider (Jan 6, 2012)

A bit off topic. But I'm 220pounds on a 29er, I found the best thing I ever did was convert to tubeless+sealant I run 35psi rear and 20/front. Tonns of grip and never any flats
Arch ex rims and a no tubes kit = win


----------



## mark! (Jun 1, 2012)

Unless I'm riding a sandy trail or soft trail, I'm usually around 32-35 front/rear, for a few trails around here I'll run lower rear for sand etc. I'm 285/290lbs.


----------



## Kajjal (Dec 14, 2013)

Check the sidewall of the tyres for a suggested pressure range. I am about 220lbs and run both at 40psi as I prefer the ride and it makes punctures a lot less likely where I ride.


----------



## Locool (Feb 25, 2006)

I don't know what wheels you have but check the rim tape for any spoke or sharp edge protruding through. And then go tubeless. It's a ride changer in that there are no more pinch flats. We're about the same size and I used to pinch flat regularly. 7-10 years ago went tubeless and tire issues do not effect my riding at all, except when my inner weight weenie takes over and I try a rear tire that is too small or race orientated. The AKA is such a tire I tried and found that, although it has good volume, it is for lighter riders or race only applications. The Geax Saguaro 2.2 has good volume and tread for an example. I ride 23-25 up front and 32-35 out back. Go tubeless, get more aggressive tire and ride on.


----------



## Bttocs (Jun 21, 2014)

Thanks for the info. Like you all have said, the tire size and type require higher pressure for someone my size. BTW, my rims are 24mm wide, Weinmann Disc Bull's. I will work on my technique of un-weighting as well. I figure I will ride the tires till they get worn and then convert to larger, stiffer, tubeless set up. Thanks again. It seems that 40 is a bit high, but it's not completely out of whack for my situation. If went from 40 to 35 psi and got pinch flats. Maybe 38 or 37 will work and ride a little softer. Time for small psi changes to fine tune.


----------



## tahoebeau (May 11, 2014)

The rule of thumb for mountain biking is you want lower pressure for rough rocky terrain and can run higher pressure if you want for smoother trails. If your hitting up rock gardens then you ned lower PSI for your tire to be able to conform to the terrain and roll over without losing as much speed. Higher pressure will make the tire deflect off the chunk. 

If your not able to get your pressure to at least below 35psi or ideally 30psi without pinch flats then you may want to take a look at you equipment. 2.2" works good for a light rider in rough terrain, but for clydes as most things go, you need bigger equipment. Wider tires will allow you to run a reasonable PSI below 35 and preferably below 30 due to more volume. I ride in the mid 20's due to the rough terrain in Tahoe with wide 2.5 front and 2.4 rear tires and 25mm inner width rims.

You say your rims are 24mm wide. Is that inner or outer width? If it's outer width that is probably too skinny for rough terrain being a clyde. Finally, tubeless would stop pinch flats, but you will still have issues with rim dents running such a skinny tire on skinny rims in the chunk.

Tires and their pressure is the most important component on a mountain bike. Trying to run skinnier tires to lose a few grams is a bad idea if your riding in the rough and will hurt the performance much more than what you gain from a little less weight, even if it is in the wheel.


----------



## Bttocs (Jun 21, 2014)

My rims are 24mm inner width, about 30mm outer width. So they seem reasonable, maybe a little narrow? The 2.2 width GEAX AKA tires came on the bike, Airborne Seeker, about 2 months old. Sounds like they are not the ideal tire for my weight and rocky terrain. At 40 psi rear, 35 psi front, they are definitely bouncy. They feel a lot better at 30-35 psi, but they go flat after almost every ride. Up to 40 psi rear and no flats.


----------



## mabrodis (Oct 19, 2005)

Bttocs said:


> They feel a lot better at 30-35 psi, but they go flat after almost every ride. Up to 40 psi rear and no flats.


Going flat after a ride is over should have nothing to do with a pinch flat. A pinch flat will be flat instantly and often times end up denting your rim because you can't stop the bike fast enough.

Btw I've seen several new tubes with pinhole leaks which you can only see when compressing the tube under water for a long time. I guess it's possible a leak like that could 'seal' itself with higher pressure pushing it harder into the tire, seems unlikely but I wouldn't say impossible.


----------



## huckxc (May 11, 2012)

Pushing 225 @ 5'10".. I ride between 42 and 45 psi on 2.2s. Small blocks and slant 6 on the front. Haven't had a flat yet this year. I do any and all gardens everyone else does. Wet flat chambered rocks, mud uphills, short sprint tough climbs...name it and I'll high pressure do it. All FS too....love your pressure, high or low... It's your story to tell!


----------



## mongreluc (Aug 9, 2014)

i would be prone to agree i am up around 275 and i ran 40-50 pound range with a 2.3s front and back and don't have an issue with flats or traction in pea gravel


----------



## Bttocs (Jun 21, 2014)

The flats I have been getting are slow leaks that take a day or two to go flat. It has happened about 3-4 times now. They are right where the typical "snake eyes" holes occur, but they are only on one side, never both. They are pin holes that I find using water. I am going to try some talc in my tires next time I take one off the rim. I think it is a variation on a pinch flat due to hitting a sharp rock on one side and getting a local compression. At 40 psi, they just don't happen. At 35 psi they start happening again if I ride rocky trails. It seems that 40 psi is higher than most run, but not out of whack for my situation. Thanks all for the info


----------



## mongreluc (Aug 9, 2014)

do you feel as though your getting more traction when you run them at 35 then what you do at 40 if not just run them at 40


----------



## Bttocs (Jun 21, 2014)

I do think the traction is better at 30-35, but the biggest difference is the ride quality. The bike bounces over rocks and ruts like a pogo stick at 40+. It calms way down when the pressure is close to 30. I have a hard tail, so like someone above said, the tires, especially the rear, are part of the suspension.


----------



## scottzg (Sep 27, 2006)

tahoebeau said:


> The rule of thumb for mountain biking is you want lower pressure for rough rocky terrain and can run higher pressure if you want for smoother trails. If your hitting up rock gardens then you ned lower PSI for your tire to be able to conform to the terrain and roll over without losing as much speed.


From what i've seen, this is only true for slow riders.


----------



## tahoebeau (May 11, 2014)

scottzg said:


> From what i've seen, this is only true for slow riders.


Then you haven't seen any fast mtb riders.

On a mountain bike you will always be faster running a lower tire pressure than a higher pressure whether you ride DH, trail, AM, XC, Enduro or whatever you want to call it. For some reference on how tire pressure works for mountain bikes here is a good article. Very thorough with references and all.

Tire Pressure and Width | RIDING FEELS GOOD

As far as what a fast riders looks like and what they run for tire pressure check out some videos of these guys:
Jerome Clementz runs 22psi front 25psi back
Sam Hill runs in 23 to 25 front and 28 to 30 rear
Jared graves runs 27 front 30 rear

You will be very hard pressed to find a pro enduro rider who rides above 30psi. Ya, these guys may be lighter than us clydes, but the courses they ride and amount of speed and stress they put on their tires is probably greater than anything us heavy guys could do mashing as hard and as fast as we can on the gnarliest course we dare to ride.


----------



## singletrackmack (Oct 18, 2012)

Great article. I think I will add it too the thread I started regarding whether or not bigger riders should ride bigger tires. People still seem to be under the impression that running higher PSI will reduce rolling resistance.

It's funny, when my roadie friends go mountain biking they just can't seem to wrap their head around the fact that lower PSI will make the bike faster. They always ver on the side of increasing their tire pressure, even after I remind them that ideal tire pressure for MTB is the opposite of road.

The rule of thumb for me is to run as low PSI as possible without risking a pinch flat or tire roll. If I have to run over 30 psi to prevent a pinch flat due to the trail, then that means I am not running enough air volume and need a wider tire and/or wider rims.

Ran across this article and video on pinkbike and it also does a good job of explaining the benefits of running lower PSI and the negatives of running it higher than needed.

Tech Tuesday - Find Your Tire Pressure Sweet Spot - Pinkbike


----------



## scottzg (Sep 27, 2006)

tahoebeau said:


> As far as what a fast riders looks like and what they run for tire pressure check out some videos of these guys:
> Jerome Clementz runs 22psi front 25psi back
> Sam Hill runs in 23 to 25 front and 28 to 30 rear
> Jared graves runs 27 front 30 rear
> You will be very hard pressed to find a pro enduro rider who rides above 30psi. Ya, these guys may be lighter than us clydes, but the courses they ride and amount of speed and stress they put on their tires is probably greater than anything us heavy guys could do mashing as hard and as fast as we can on the gnarliest course we dare to ride.


What a pro racer is doing has very little to do with what the rest of us are doing, especially on this forum. We buy our own parts, put 20-50% higher loads into our equipment due to weight, and aren't riding smoothly to chase the clock. In this thread you're comparing guys riding DH tires/ DH tubes/tubeless to some dude running tubes on an XC hardtail. Ridiculous.


----------



## tahoebeau (May 11, 2014)

Maybe i am confused by what you meant when you said that only slow riders use low tire pressure in the chunk and high pressure on smooth flow trails. Please explain.

But regardless, plenty of people in this forum and on this thread ride tubless, ride smoothly and compete in local races or race the starva clock.

Also, did you read the article? It makes it pretty clear that lower pressure will help make you ride faster. Even for XC. So again, what did you mean by only slower riders run low psi in the chunk and higher psi on smooth flow trails?


----------



## tahoebeau (May 11, 2014)

On another note, if an enduro racer damages his wheel beyond repair, he's done, out of the race, not allowed to continue. And if he gets a flat, he's pretty much out of the race since he will loose valuable time fixing the flat. So even though he doesn't buy his own equipment, that doesn't mean he can risk damaging it. Plus, they don't ride DH tires, they ride enduro tires which are much lighter since climbing is part if the event and are no where near as strong as pure DH tires where weight is not really a concern.

Also, the stress they put on their equipment is probably higher or at least equal to the stress we clyde's put on our equipment at a much slower speed.


----------



## scottzg (Sep 27, 2006)

tahoebeau said:


> Maybe i am confused by what you meant when you said that only slow riders use low tire pressure in the chunk and high pressure on smooth flow trails.


A rider using low pressures in chunk is usually a rider that is focusing on each rock individually. Slow.



tahoebeau said:


> On another note, if an enduro racer damages his wheel beyond repair, he's done, out of the race, not allowed to continue. And if he gets a flat, he's pretty much out of the race since he will loose valuable time fixing the flat. So even though he doesn't buy his own equipment, that doesn't mean he can risk damaging it.


Again, elite riders racing whatever are not intermediate clydes knocking hardtails around in the woods. It's not a helpful comparison.



tahoebeau said:


> Also, the stress they put on their equipment is probably higher or at least equal to the stress we clyde's put on our equipment at a much slower speed.


 The peak stress is probably similar, but the clyde is gonna be bumping against it a lot more frequently. It's why you hear about clydes that crack alu frames every couple years, and why we need to run more air and/or stiffer tires for them to perform correctly.

FWIW, my 6" bike has 2.35 UST DH tires and runs 30f/35r psi. My long travel hardtail has 2.25 tubes and runs 32/40. I weigh 230lbs and have been riding for 9 years.


----------



## Bttocs (Jun 21, 2014)

In doing searches on tire pressures, I came across this post which is the best description I have read for what tire pressure to use on your mtb. It basically summarizes what the articles listed above say. FWIW, my tires (Geax AKA 2.2) say the pressure range is 35-60 psi. 

Copied from:

Squash

The reason that most mtb tires are faster on dirt at lower pressures is really rather simple. A tire at lower pressure will flow or comform to bumps, smaller rocks, or square edged obsticals. A tire at higher psi doesn't do this, rather it has to make contact with the obstical and climb over it. This creates a bump that you can feel and in many cases the tire looses contact with the trail surface. It takes more time for the tire to bump over the obstical than it does to have it flow over it. The effects of higher pressure are, slower speed, less traction, less control. The lower pressure tire will have the opposite effect. But as the others have noted there is a limit to how low you can go. Rider weight, riding style, tire volume, tire construction, terrain, etc. all work to determine the "sweet spot" for a given tire. The sweet spot is that golden compormise pressure where the tire provides the best traction and performance without feeling squirmy or being so soft that you ding rims, etc. And I've never had two different tires that had the same sweet spot, and it takes a bit of work to find it. But if you go at it right it can be allot of fun.

As for where to start, Surly29 had it right. Start with the lowest recommended pressure for the tire and ride it. If you don't get a pinch and the tire doesn't feel squirmy on the first run, drop pressure on the next run by 2 or 3 psi. If you do get a pinch or tire squirm up it by 2 or 3. So drag your pump and your bike to the trail and have fun. Oh and just as a side note, make sure you take a couple of spare tubes and have an inflation device along on the bike. Cause you will most likely pinch flat at least once.


----------



## Alias530 (Apr 1, 2013)

6'6" 240lbs

DHF front, HR2 rear
24psi / 28 psi
Tubeless


----------



## scottzg (Sep 27, 2006)

Bttocs said:


> As for where to start, Surly29 had it right. Start with the lowest recommended pressure for the tire and ride it. If you don't get a pinch and the tire doesn't feel squirmy on the first run, drop pressure on the next run by 2 or 3 psi. If you do get a pinch or tire squirm up it by 2 or 3. So drag your pump and your bike to the trail and have fun. Oh and just as a side note, make sure you take a couple of spare tubes and have an inflation device along on the bike. Cause you will most likely pinch flat at least once.


This doesn't really work though. Squirm will limit what you will try without your being aware of it; that 'out of control' feeling comes sooner. You end up not knowing that you're slow. Or using tire pressures to compensate for poorly tuned/sticky suspension.


----------



## tahoebeau (May 11, 2014)

I agree, Surly29 is spot on. Running the lowest tire pressure possible without risking pitch flats or tire squirm will be faster, give more traction, increase rollover, decrease resistance and make for a overall better ride regardless if you ride a rigid, HT or full squish, xc or AM. 

Tire squirm is very easy to be aware of and is instantly noticeable. You will be aware of it right away, in which case your tire pressure is too low. 

As far as lower tire pressure making you slower either on a regular singletrack or chunky section, that just doesn't make sense. If running higher pressure had an advantage in speed, then we would see racers, xc, enduro or whatever running higher pressure. But they don't, they all run the lowest possible pressure for a very good reason. These guys look for an edge wherever they can get it, if they don't run higher pressure than needed there is a very good reason for that. Also, we would see articles suggesting to run higher pressure than needed, but I have never read a single one that says that. They pretty much all say to run the lowest pressure possible, and increase pressure if your concerned about pinch flats in the rough or feeling the tire squirm. 

Also, tires are a far more important component than suspension. In fact, you don't even need suspension to mountain bike. Far more important to make sure your bike is griping the trail and providing maximum rollover and lowest possible resistance than fine tuning your suspension. If your tires ain't right, your ride ain't right no matter how much you tweak and tune the suspension.


----------



## Bttocs (Jun 21, 2014)

I have been avoiding the sharp rocks on the trails lately, and I am finding I can go with lower pressure and not get flats. Slowly dropping from 40psi rear to about 36psi rear. I am not sure if I can go lower without a change to a beefier tire, since I am about 245lbs. 

Thanks for the info and I am confident now in the approach to finding out where I need to run my tires.


----------



## tahoebeau (May 11, 2014)

Bttocs said:


> FWIW, my tires (Geax AKA 2.2) say the pressure range is 35-60 psi.


As far as the tire pressure range, you should not be concerned about going below that range. Below is taken from a bikeradar article, but I have seen the quote form from Schwalbe in a few articles about tire pressure:

"Tire pressure is a critical component in getting the most out of your mountain bike. There are a number of variables that go into figuring out the ideal pressure range for a bicycle tire. Many of those are completely out of the control of the manufacturer, causing them to err on the side of caution. "It's a lawyer thing, for sure," said Schwalbe's North American OE sales manager Henry Horrocks.

A tire's maximum pressure is not the pressure at which it will burst like a balloon; more often than not it's the rim that can't withstand the pressure. Not all bicycle rims are created equal; some can withstand much higher pressures than others. Companies have no way of knowing which rims you, the consumer, will be pairing with their tires. Consequently, their maximum recommended pressures tend to be conservative.

For mountain bikers, the maximum pressure rating generally isn't the issue, as most riders run well below this number. Many - myself included - often run pressures well below the minimum rating, especially with tubeless setups.

Why go lower? Well, it can allow your tires to roll faster and absorb more trail irregularities, and can increase traction as well as comfort. There are numerous studies that offer supporting evidence."


----------



## Bttocs (Jun 21, 2014)

I am now down to 28 psi front and 32 psi rear. This feels really good and is probably about where I will stay until I go tubeless or get beefier tires. This works as long as I stay out of the rock gardens. Will raise it up if the trail requires. No flats since I started to lower the pressure a little at a time. Thanks everyone for all the useful info.


----------



## Tjaard (Aug 17, 2007)

Bttocks, it sounds like you've got the idea:
Run the lowest pressure you can without squirm or pinch flats.
If this leaves you with a high pressure compromising ride quality you can do the following:
-Run a high volume('wide') tire with a reinforced casing
- run it tubeless (as noted, this still hits your rims)
- once tubeless, install Schwalbes Procore system when it comes out.
- get a full suspension bike

I'd say 40 psi sounds normal for a guy your size on a hardtail in a rock garden


----------



## BR101 (May 10, 2014)

I have a Airborne Goblin and run the AKA 2.2 tires at about 50psi. I am 290lbs and it flys..


----------



## Tystevens (Nov 2, 2011)

I'm about 245, and would pinch flat the hell out of my tubes if I hit my local rock gardens at less than 40 psi (when I ran tubes, that is). They are full of sharp rocks which can't be avoided, and I like to hit them at as much speed as I can. I'm with scottzg -- low psi going fast in a rock garden with heavy rider is a recipe for pinch flats. With tubes, I'm always around 40 psi front, 45 rear.

Tubeless, I go a bit lower, but I don't like feeling my tires squirm in the corners, so I still stay around 30-35 with my tubeless setup.


----------



## theMISSIONARY (Apr 13, 2008)

checked your rim tape? that was giving me hell for quite some time.....


----------



## Bttocs (Jun 21, 2014)

Hello everyone, thanks again for all the great info. I wanted to post an update because I think I finally sorted out my "pinch flat" issue. I did get a couple of true pinch flats, but what was causing most of my 8-9 flats this season is small thorns that were stuck in the tire. They were imbedded in the rubber and hard to see. They didn't quite stick out and touch the tube, unless I lowered the pressure enough that the tire wall started flexing a lot and then they would poke through. I looked at the tire with a magnifying glass and pulled 2 thorns out of the tire with needle nose pliers. Haven't had a flat since and I am down to high 20's for tire pressure. Feels really good on my hardtail bike. I now have some "tire suspension" on my bike for those smaller type roots.

In New England we a have thorn bushes that I like to call "picker bushes" and I guess I managed to run over and imbed some thorns in my tire.


----------



## Alias530 (Apr 1, 2013)

I couldn't imagine that... between road and mountain I got 1 flat all year and it was from a pothole on my road bike. Had to choose between hitting it and hitting a car, so the choice was simple


----------

