# MTB Tire Pressure



## WoodCore (Apr 16, 2009)

Obviously this will vary for numerous reasons but what tire pressure do you typically run on your MTB?


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## o3jeff (Apr 17, 2009)

Around 37.


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## bvibert (Apr 17, 2009)

It depends on how anxious I am to change a pinch flat.  I like around 35, but it's usually more like 40 to help keep the pinch flats down...


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## RootDKJ (Apr 17, 2009)

I run around 40+ as well


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## Greg (Apr 17, 2009)

Started with 37 this season. Going to probably soften them a bit.


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## JD (Apr 17, 2009)

30psi, but I run 2.3s.


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## RootDKJ (Apr 17, 2009)

Besides from "pinch flats" what are the advantages of running at a lower psi?


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## Greg (Apr 17, 2009)

RootDKJ said:


> Besides from "pinch flats" what are the advantages of running at a lower psi?



Better traction, but more rolling resistance. And lower PSI is not an advantage in terms of pitch flats. They are more likely at lower pressures. It's a trade-off. I'm light so I can get away with lower 30's. A big guy like Brian is going to pinch flat at the same PSI that works fine for me.


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## o3jeff (Apr 17, 2009)

RootDKJ said:


> Besides from "pinch flats" what are the advantages of running at a lower psi?



Better traction


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## RootDKJ (Apr 17, 2009)

Greg said:


> Better traction, but more rolling resistance. And lower PSI is not an advantage in terms of pitch flats. They are more likely at lower pressures. It's a trade-off. I'm light so I can get away with lower 30's. A big guy like Brian is going to pinch flat at the same PSI that works fine for me.





o3jeff said:


> Better traction


Cool, thanks.  When I first started biking, I was getting them all the time until I raised up my psi.


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## marcski (Apr 17, 2009)

I run 2.35"s at 40 psi.  I get plenty of traction....and like the firmer feel.  When I ride in the winter...in snow and/or some ice...I will lower the pressure some...but that is rare....where I actually lower the pressure.


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## rueler (Apr 17, 2009)

I usually run 35 psi...but, could easily go much lower because I run a tubeless set-up...the trails have been really dry lately so I have been running around 40 psi so I can roll a bit faster.


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## bvibert (Apr 17, 2009)

rueler said:


> I usually run 35 psi...but, could easily go much lower because I run a tubeless set-up...the trails have been really dry lately so I have been running around 40 psi so I can roll a bit faster.



Do you have a UST setup?


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## rueler (Apr 19, 2009)

bvibert said:


> Do you have a UST setup?



Yeah...one of my tubeless wheel set-ups is definitely UST...the other probably is too!


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## gorgonzola (Apr 20, 2009)

35ish w/ tubes


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## Greg (May 4, 2009)

I rode Friday night and checked pressure on Saturday for the first time in a few weeks and I was well below 30. :-o Luckily, I didn't pinch flat, but I only brought it up to 35.


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## Marc (May 4, 2009)

Aside from better traction, riding with lower pressure will generally be conducive to NOT bouncing off every rock and root in the trail.  Usually you'll have, or at least feel like you have, better control.

I ride around 35.  I could probably get away with lower, but since I have softie full suspension and I abso-fing-lutely hate changing flats on the trail, I'll stay there.


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## Talisman (May 4, 2009)

Marc said:


> I could probably get away with lower, but since I have softie full suspension and I abso-fing-lutely hate changing flats on the trail, I'll stay there.



I run at ~35 to 28 PSIG to avoid pinch flats.  My typical pinch flats come from a slow leak from a thorn early in the ride to a flat while biting flies are at their worst.  Fixing flats is fun in a well lit area with cold beer and no deer flies.  Kneeling in the mud with a swarm of mosquitos as night falls while fixing the flat is another story.


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## bvibert (May 19, 2009)

Interesting study on rolling resistance off-road:

http://www.bicicletta.co.za/Downloadable docs/Rolling Resistance Eng illustrated.pdf

Fat tires and low pressure seem like the way to go. :beer:


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## Greg (May 19, 2009)

bvibert said:


> Interesting study on rolling resistance off-road:
> 
> http://www.bicicletta.co.za/Downloadable docs/Rolling Resistance Eng illustrated.pdf
> 
> Fat tires and low pressure seem like the way to go. :beer:



I found these sentences amusing:



> The rougher the ground, the greater the advantage, as the data obtained on grass proves.





> ...but the rougher the ground, the greater the effect, as the grassy ground shows.



:blink: I never thought of grass as being "rough ground"... :lol:


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## bvibert (May 19, 2009)

Greg said:


> I found these sentences amusing:
> 
> 
> 
> ...



Well, I don't think they meant someones yard.  Sounds like it was more like the grassy area next to a road.  It's not necessarily flat under that grass.  They should have tried the test on rocky and/or rooty terrain though.


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## bvibert (May 24, 2009)

bvibert said:


> It depends on how anxious I am to change a pinch flat.  I like around 35, but it's usually more like 40 to help keep the pinch flats down...



I lowered my pressure in the rear a bit today, since I'm on the HT now, and sure enough I got my first pinch flat since switching to 40psi last year.


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## Greg (May 24, 2009)

bvibert said:


> I lowered my pressure in the rear a bit today, since I'm on the HT now, and sure enough I got my first pinch flat since switching to 40psi last year.



You owe me a beer. I predicted that as soon as you started releasing air.


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## JD (May 24, 2009)

You have to be smooth to take full advantage of low pressure...you can't just sit and spin thru everything.


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## bvibert (May 24, 2009)

Greg said:


> You owe me a beer. I predicted that as soon as you started releasing air.



I don't remember making that deal, but I'm sure I owe you one or two anyway.


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## bvibert (May 24, 2009)

JD said:


> You have to be smooth to take full advantage of low pressure...you can't just sit and spin thru everything.



Smooth is something I've never been accused of being.  However, I was far from just sitting and spinning through everything today.  I was up out of the saddle quite a bit.  The pinch flat happened when I was descending a rocky section and the rear tire inadvertently came down on a jagged rock.

But, yeah smoothness is definitely something to work on.


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## Greg (May 27, 2009)

You were running way too low on the rear on Sunday Brian. You probably released 10+ PSI. I've found a quick half second tap on a presta valve releases easily 2 PSI. When I was riding behind you, that tire was all squashed.


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## JD (May 27, 2009)

bvibert said:


> Smooth is something I've never been accused of being.  However, I was far from just sitting and spinning through everything today.  I was up out of the saddle quite a bit.  The pinch flat happened when I was descending a rocky section and the rear tire inadvertently came down on a jagged rock.
> 
> But, yeah smoothness is definitely something to work on.



Didn't meant to sound like a dick there....sometimes it just happens.


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## bvibert (May 27, 2009)

JD said:


> Didn't meant to sound like a dick there....sometimes it just happens.



I didn't think you were being a dick, sorry if I came off too defensive sounding.  I definitely have to work on smoothness.

For now I'm just gonna stick to 40 psi, even if means a rougher ride.


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