Mountain Biking - PSI anyone?

So after looking over my new Rockhopper 07 and with a fingerprint duster mind you I found that the tires on it read that they take 35-85 psi. My question to everyone who's been doing this much longer than me is... What pressure do I use for trails with roots, stumps, up hills, down hills, etc. Oh, and 85 psi seems like it would make the tire explode. I have been filling them to about 40 psi.

Thanks

On my ht

30psi front
30ish rear

Dually
30psi front
45psi rear

on my bike i have 45-50 in front and rear.

I generally run between 35 and 40 psi depending on course and conditions. However I run tubeless so this probably won't help you out too much.

I run 40-35ish

Its not worth risking a pinch flat to go any lower imo.

35 front, 40 rear, full rigid. Front is a 2.1 and rear a 2.3, both Contis, though....

I run 40 front, 50 rear on both my HT and FS.

about 40 psi on may ht

Most of the time I'm using by bike on the street, so both wheels are around 55-60 psi. Sometimes I lower the front for more grip. On trails though, both go down to 40-45.

BMX: 110 front, 120 back.

Fully: 35 front, 40 back.

Hardtail: 40 front, 45 back.

for my boulder i pump them all the way up to 60 no matter what course i'm racing or riding. I love a harsh ride and i like to feel absolutely everything.

I run 40-35ish

Its not worth risking a pinch flat to go any lower imo.


I should mention I only run dh grade tires. Pinch flats happen a lot less infrequently. If I were running standard xc tires...45ish probably.

(xc ht) 40-45 front and back

I ran 50 front and back a couple of days ago and noticed that my rear slips on some rocks. And my fronts a little squirmish. I think I should back off about 5 lbs each and try again.

Everyone will ride different PSI depending on their weight. So you can't really go off someone else. (Just try experimenting...buy a pressure gauge and take it on the trails with you to check different pressures and get an idea!).

But here is mine anyway:

50PSI - Road, Bike Paths Gravel

35PSI - Hard Packed single track, loose gravel, going faster offraod, roots, logs, jumps.

25-30PSI - Wet, Muddy, single track, very loose conditions. NO jumps, NO roots, NO logs. (pinch flats arn't the funnest thing to fix and have).

:)

I'll also mention i'm quite light! I also tend to run a lower pressure by 5psi in the front then in the back.
:)

My 5000lb truck recommends 35 psi and my 2900lb coupe recommends 35 psi. I don't get it.

The size of the tire makes a big difference for autos/trucks ...same would also apply for your bike. On my 4000# 4x4 I run under 15psi in the rocks on 36" tires. otoh to tow 6500# I need 85 psi or so.

On my Rockhopper with 2.2" tires I run 35-40 rear and 5# less in the front. For rocks, roots and general rough stuff the lower the pressure the better the traction ... offset by avoiding pinch flats. For faster dirt trails higher pressure will be faster. You need to experiment and find what works best for your weight, trail conditions and riding style.

I ride 25-32 rear and 55-65 front.

45-50 for street, 35-40 for trails.

I mostly ride on the street and run 80psi front and back(max on the tires). I ride like that on trails too but sometimes air down if i need more grip. Higher pressure=lower resistance=less work.

You roll a lot faster with a higher PSI and it's easier to pedal. But on the downside, you lose grip.

it depends more or less on the tires.. width... and what they can handle