Tyre psi

[stilly]

Hi all just wondering what psi should I be running in my front and rear tyre, I have had around 7psi in both, is this too much or not enough,

[benbeta23]

I run 4 1/2 in the rear and 5 1/2 in the front, Depends on your weight though really.

[eastcoasthopper]

I run between 3 and 4 psi in the rear and 5 to 7 in the front. If it's muddy and really slippery I run a bit lower, if it's dry and rocky, I run it a bit higher. I no longer use a gauge, just my hand. I like the front to be fairly firm and the rear I can put my thumb against the center of the tread and push it in about halfway to the rim. BenBeta23 is right about the weight thing too. If you're heavy and run it too soft, you risk denting the rear rim and getting a front flat.

Edited December 15, 2010 by EastCoastHopper

[helloyes]

I run 6psi in the front and 2.5-3 psi in the rear seems to work down here in muddy gloucestershire !!!

[chewy]

probably what the other guys said but also dont forget that ambient temperature makes a big difference as well cold tyres are stiff like old trials riders

[stilly]

Thanks for the info I will try 4 rear and 7 front f now and go from there.

[neo]

Tuning tyres is like tuning suspension and one effects the other too. Be aware of the limitation and try-test, try-test, try-test, try-test, try-test, try-test, try-test, try-test!!

Best of Xmas balance to you

Neo

[shercoben12]

I run 2 -2.5 psi (but I am only 12 and not that heavy!)

Not sure what to run in the front at the moment but it is about 7psi and always tends to slip away from me on down hill turns

[zippy]

Shercoben12 The front tire slipping away on down hill turns could be too much air pressure (sidewalls too hard and not flexing with the downward pressure of the bike as it tries to turn to the side. If it flexes a little then the tread contact patch will stay put, if it don't flex then tread contact patch slides), or possibly technique (for example too much front brake applied will not allow tire to rotate well and it slides down hill, someone once told me about gravity but I am not so sure it exists. Look at Toni Bou)

But if you are running 2 - 2.5 psi in the rear and that works good for your weight, I would suggest dropping the front pressure down to about 5 and adjust from there to see if there is a difference on those downhill turns.

[shercoben12]

Thanks zippy

Just been down to my woods and tried what you recommended it worked I might even try lower ,what would you think would be as low as I could go.

I now understand what you mean by tyre flexing.

Thanks alot

Ben,12

[tony27]

Probably safest to not go lower than 5 in the front especially if you ride rocks/slabs, too low on grippy stuff has a quite nasty effect where the tyre resists any steering imputs, if turning it wants to keep turning & if going straight then it takes a fair amount of effort to start the turn then as much to stop the wheel from turning more than required

[shercoben12]

ok thanks

[zippy]

Thanks zippy

Just been down to my woods and tried what you recommended it worked I might even try lower ,what would you think would be as low as I could go.

I now understand what you mean by tyre flexing.

Thanks alot

Ben,12

Glad it worked for you. I would tend to agree with Tony27 that about 5 is probably the lowest to go. What you want is a good middle ground of a little tire flex to keep a contact patch in place but also enough air so that the tire will still turn when and where you want it to go.

[samy]

I normally run with about 4.5 in the rear and 6 in the front but last weekend i was at a trial that was quite cold (well, for Australia!) and the tyres didn't seem to want to flex very much. There was a small amount of water and wet rocks but a fair bit of mossy, damp hillsides and on my first lap i was slipping all over the place having a hard time of it. I dropped down to 3.5 in the rear and 4.5 in the front and it made a big difference! I almost cleaned the rest of the day! It's amazing how much difference 1psi can make!

cheers