# tire psi ?????



## VAC357 (May 16, 2011)

A while back I read a thread concerning tire pressure. Can't find it, so pardon the redundancy. 

How much air pressure are you using? I know there are many variables, but is there a "chart" that's somewhat suggestive?

I'm 330# and have ridden trail with 30-33psi. However, it's much different on pavement and I have to add more. Turning corners can be a little sketchy at times, yet I thought enough air was used.

How much do you use? Have you ever inflated to the point of blowing the tire? Is 40psi safe and realistic?

Thanks,
V


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## O2begrn (Jul 19, 2012)

interested also thanks for asking


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## BigKahuna (Jan 19, 2004)

In many years of riding, I've NEVER used a gauge on my mountain bike tires. I go purely on "feel". 

But I always use on on motorcycle tires!


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## timk125 (Jun 28, 2010)

I'm 250 and run around 40 on 2.4 tires. Any less in the rear and it feels like I'm riding with a flat, I try and run less in the front because it feels like I have more grip. Not saying you do get more grip that's just what it feels like to me.


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## SeaHag (Jul 14, 2011)

I'm 260 and just started running about 35 pounds front and rear since reading the articles about lower tire pressure being more energy efficient off road. It's taking a little getting used to but the traction does seem to be superior.

PS: This is with MAXXIS Ardent 26 X 2.4" tires


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## fatguybiking (Jul 14, 2012)

I'm 315 now, but was as high as 343. I run my rear at 60psi and my front at 40. I'm not sure if it is my stock tires, but even at 60 my rear tire looks like it is low on air. No problems thus far, but it seems like I'm in the extreme minority running that high. Pretty sure it is a 26 x 1.95 tire.


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## jeffscott (May 10, 2006)

VAC357 said:


> A while back I read a thread concerning tire pressure. Can't find it, so pardon the redundancy.
> 
> How much air pressure are you using? I know there are many variables, but is there a "chart" that's somewhat suggestive?
> 
> ...


Max tire pressure is quoted on the tires themselves...

Some rims have a max inflation pressure....Stans Mavic Shimano XTR....mostly higher end tubeless set-ups....see rim documentation...

Rule off thumb ride.....in rough terrain ride as low as possible without the tires squirming in the corners....or pinch flatting...

Smooth riding ride a max inflation limit...

We actually have some rides that have a relatively smooth climb....then a very rough downhill.....we will let some air out for the downhill section.


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## phoeve (Mar 10, 2008)

6'8"/275 on Weirwolf 29-2.55's. 30psi rear, 25psi front. 1 FS bike and one hardtail. I run tubeless on the HT and tubes on the FS.

30/25 gives a nice ride over roots and rocks without pinch flats w/tubes. The bike tends to not stall on roots or rocks either. Nice traction too. Sometimes I go even lower psi on the tubeless bike.

40+ psi would jar my molars loose. Not sure how you guys survive that. 

Your tires are your best, most compliant suspension. Go big with low pressure !


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## Joules (Oct 12, 2005)

there is no chart, it's sort of like asking 'how long is a rope?'

if you are pinch flatting, or the bike gets weird on corners, add air. If the ride is harsh, let some out. 40psi is within every tire or rim's max spec I've seen. 

another thought: it's pretty common to run more pressure in the rear than front. Maybe take that into account when making adjustments.


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## mark! (Jun 1, 2012)

6'1 350-360, I run 40 in the rear, 38 in the front.


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## masonmoa (Jul 11, 2011)

6'5" 330
Running tubeless on both 29" and 26"
32ish front 2.4
40ish rear 2.2


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## sss18 (Jan 11, 2011)

I am 6'3 210 and I typically run 30 in the back and 26 in the front. When I was heavier I ran more in the back typically 35 to 40.


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## Leech73 (May 4, 2012)

6'8" 240
Tubes on a 26" with Geax Saguaro 2.2
Rear 30, Front 28


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## BigKahuna (Jan 19, 2004)

I actually checked, and here's what I found. I weigh 285 and have 2.2 Kenda Nevgals on my 29er. 

Rear was closer to 40 and the front closer to 35.


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## 4nbstd (Apr 12, 2012)

220 lb, on rigid 29er, Panaracer Rampage 2.35".

I just inflate till the beads hook and the deflate to the point where beads stay hooked. Usually between 25-30 psi for both front and rear.


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## bigwooly (Aug 14, 2012)

good info here i'm trying to figure out what to get for my 1st adult MTB now i know that these tires need way way way less PSI than my road bikes.


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## Tystevens (Nov 2, 2011)

240# here.

With tubes, always 35-40 psi front, 40-45 psi rear. I hate pinch flats.

Tubeless, subtract 5-8 psi. So far, so good, at least until I ripped a hole in the rear tire sidewall last ride (I'm back to a tube in that tire for now!).


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## druidjaidan (Aug 14, 2012)

I tried running 40/40 and just couldn't keep grip on the trail

So I dropped to 35/30 and my ride it much much better. The rule I've heard is basically goes as low as you can until you start hearing/feeling rim impacts (or you get a pinch flat). Then Increase it. Or keep reducing it until you stop feeling a difference (assuming you don't get pinch flats rim impacts)


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## bishop29er (Aug 9, 2012)

Good thread! 
I'm 6'6" 240 and I run 33 psi front, 35 rear on trek xcal 29er ht with stock bonty 29-1 experts. I ran them as low as 28 psi but they started to get squirrelly in corners. Just converted to schwalbe tubeless setup, so hopefully I'll be able to run lower pressures.


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## brent878 (Apr 17, 2007)

200#'s here. All 29er tires and running stans tubless.

WTB Dissent 2.5" about 20 psi
Kenda Slant six 2.2" 33 psi
Kenda small block 8's 2.2" 38 psi
Kenda Navagal 2.2" 32 psi
Halo Twin Rail 2.1" 40 psi


It really depends on individual tires and sizes. I run them as low as I can while they still feel stable in the corners. I find that bigger and thicker sidewalls let me run lower tire pressures and the thin light tires I seem to have to really pump them up. Best way is to expermient. But be careful of max tire pressures both on the tire and rim. My stans flows rims says max pressure of 38 psi. I have had a few tires blow off rims due to too much pressure and every time it ruins the tires. The bead gets streched and they blow off very easy after that.


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## ProfGumby (Feb 27, 2008)

There is a lot of sand around here, so I tend to run 55 psi in the rear tire and 50 up front. No science behind it but any less pressure and cornering is sketchy and I feel like I am riding on flat tires. Lower pressure on roots and rocks and the tires seem to grip the roots and want to throw me sideways off the bike...and more pressure and there is a lot of slip and spinning tires and a really rough ride. 

Like I said, no science behind it, just what I like. And if I do ride the bike on pavement (around town or some nonsense) the tires are at their max psi.


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## zx1421 (Jul 31, 2012)

in the dirt, 20 front, 35 rear, on the street 55 front 65 rear, I be 275# Carve Pro 29er


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## cautery (Aug 1, 2006)

I use Stan's "rule of thumb" formula for my tire pressures, and it seems to serve me well. I run tubeless-ready tires, Stan's tape and sealant.

Front: (Weight divided by 7) - 1 (215/7) - 1 = 29.714, round UP to 30 psi
Rear: (Weight divided by 7) + 2 (215/7) + 2 = 32.714, round UP to 33 psi

*NOTE:* NOT TO EXCEED max rated pressure on tire OR rim.

This is for trail riding... When I train on the road, I sometimes ride with slightly higher pressure to reduce rolling resistance.

Can't wait to get down to 175, when my pressures will be approx. 24 and 27 psi.

I'm an air pressure consistency freak, so I have taken THIS pressure gauge:










And replaced the gauge with a super accurate, liquid-filled pressure gauge with a range from 0-60 psi (to make sure the desired pressure is near the center of the gauge range for max accuracy) This is the gauge I used:










Hope this helps...


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## Jphill1301 (Jun 25, 2012)

I've never seemed to have a problem with my tires. Only had one flat in 300 miles. I run mostly pavement at 60 PSI.


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## CSCHMITT (Jul 26, 2011)

250 35/37


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## Tillers_Rule (Sep 11, 2004)

6'4" 200

Kenda Nevegals on both my 26 FS and my 29 FS.

26 = 35 front 2.35" tire, 40 rear 2.1" tire
29 = 30 front, 35 rear, both tires are 2.2"

This is for the southern California dry, hard pack, some loose sand, slightly rocky sections trails


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## jonshonda (Apr 21, 2011)

The problem with each post in this thread is that each tire and wheel combo has a different volume. My Stans Flow EX adds volume on its own over the C29SSMAX's it replaced. 

I don't think big dudes should ride small mtnbike tires. High volume, chubby rubber is better for clydes. You can get away with 35psi and still have some give over roots and rocks, vs 50psi on a small tire/wheel combo that will damn near shake you off the bike. 

I run a 2.2 tire front and rear, and go 28psi front and 32 rear. But today the trails were so dry and lacked much grip, I should have dropped the front a bit to see what happened.


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## atomicmanatee (Sep 1, 2012)

260# running 2.1 tubed tires 26" and 29" running about 35 rear 30 front. dropped down to 30 rear 30 front and pinch flatted the rear on my full rigid.


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## Locool (Feb 25, 2006)

At 6'5 225, I've found going 25-27 w/ non ust converted conti explorer 2.3 up front, and 35-37 rear w/ ust 2.2 conti mk works about right. I've tried converted rear tires, but found nothing that really worked w/out the occasional burp.


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## big terry (Apr 22, 2012)

im 235ish without gear, and with tubes in nevegals i have been running 40ish in the rear and low 30s up front. i pinch flat like a mofo because of the terrain i ride, and my poor form, so i like the extra pressure in the back to help alleviate those pinchers.

got a set of mavic 819 ust to set up this week. ill start off using stans formula for tubeless, but will likely run a little higher just because i like it that way.


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## Locool (Feb 25, 2006)

big terry, you'll like the change. I ride in the Colorado Rockies where every conceivable rock exists. Inbedded rock, slab rock, slate, loose, volcanic, river rock, are some of the conditions. My size and being an aggressive rider I pinch flatted w/ regularity before. I've been tubeless for a while now and tried many different set-ups, some better some disasters, but tubeless has been the constant. I don't pinch flat anymore. My failures in tubeless usage has been trying to convert lighter tires to do heavier work where the tires were not made to go.


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## phoeve (Mar 10, 2008)

*Stans Flows ROCK !!!! 18 front 20 back*

18 front 20 back
6'8" 275 lbs - Flows tubeless Weirwolf 2.55 back and Ouster 2.25 front

No burping, flats no bottoming out on roots and rocks. Ride faaaast and like a dream.

Same setup on Ventana FS and Lynskey HT.

Stans Flows ROCK !!!! They are wide and the tires seal tight.


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