Correct Tyre pressures

Best to take readings when at the ambient temperature but there is always the problem
that winter is colder (errrrr that sounds a bit obvious ). To determine the correct
pressure measure the tread depth of your tyres every 2-3 thousand miles. If they wear
even you have it correct already. If they wear faster in the centre the pressure is too high,
if they wear faster at the edges the pressure is too low. Try adjusting pressure a couple
of psi at a time. Do it this way and you'll have the correct pressure for your car and your
style of driving.

FWIW I'm running 35psi on the fronts and 34psi on the rears on my 205/45/17 non runflats. Tyre wear appears to pretty even, if a little faster than I would like.

My understanding is that if the tyres are warm when you check them then add 2 or 3 psi. That is, if you would usually run them at 36psi and they are warm when you check them, then inflate to 38-39psi. ???

Also I think so long as you keep the pressures even on each axle then really anything from 32-38psi is probably going to be okay. However, Steve's advice above is very good. You just want to make sure you tyres are wearing evenly across the tread.

hmm...interesting

thats for the replies!!!

but i still have a very confusing question...

as you suggested minigolf of raising the pressure by 2psi, that means your intentionally over-inflating the tyre. But the temp of air being pumped into the tire is cold(that is, below temp induced when driving)...This means when the tire reheats again, the tire would increase evermore in pressure, thus over-inflating more. (That explanation came out better than expected ) This is what im assuming, correct me if im wrong somewhere.

Chosta

chosta said:

t
as you suggested minigolf of raising the pressure by 2psi, that means your intentionally over-inflating the tyre. But the temp of air being pumped into the tire is cold(that is, below temp induced when driving)...This means when the tire reheats again, the tire would increase evermore in pressure, thus over-inflating more. (That explanation came out better than expected ) This is what im assuming, correct me if im wrong somewhere.

Click to expand...

He didn't mean add an extra 2psi to the tyre but to the readings on the gauge. So if 35psi
is when cold then allow 37psi if measuring when warmed.

chosta said:

I've been thinking about what pressures i should be running my tyres on. Right now i run my yoko ES100 205/40/17 at 36psi, which i think is pretty high. How do i determine the right pressure?

When i do regular checks on my tyre pressure, i realise that the air im pumping in is pretty cold, and since i drive to the service station to pump them, they are considerably warm. So does this mean i should under-inflate them by 1 or 2 psi to allow for expansion during normal driving, or do i pump them up to the suggested pressure by experts/manufacturers (thus, the expansion factor has already been factored in) ?

Thanks!

Click to expand...

Actually, you can to check the pressure at home, then drive to the service station and check the pressure again and calculate the difference. Just add the difference to the desired cold pressure you desire. Don't worry about the temperature of the air that is going into the tyre, it will not affect anything.

Steves suggestion about checking tread depth across the width of all the tires on a regular basis is spot on. Buy yourself a proper tread depth gauge, it will make the job very easy and quick. Speaking about buying, make sure you have an accurate pressure gauge. It is no place to "cheap" out. Anything you save on a cheap gauge you could easily spend on worn out tyres from under or over inflation.

Just one hobbits opinion.

SteveM3 said:

He didn't mean add an extra 2psi to the tyre but to the readings on the gauge. So if 35psi
is when cold then allow 37psi if measuring when warmed.

Click to expand...

Yep, that's what I meant.