How much tyre pressure???

[Simon Motorsport]

I am just asking myself what would be the best pressure for my tyres?

I am running 255/30/21 in the front and 295/25/21..

The reason why i am asking is because the last time when i changed my rear Tyres @ pirelli, the guys told me i was running low pressure!


Raad, i hope you can help me out:please:

[jmeister]

u need to check the pressure every week cos the expansion and contraction of the tyre means it will bleed pressure during normal driving. the road surface being v.hot doesnt help in Dubai. best solution is to get nitrogen and check it weekly.

the best pressure in your non-standard tyres should be judged by yourself. You could do the below: carry a gauge and fill on the high side. then wipe the tyre down then drive a few metres and have a look at the tyre afterwards and check how the dirt is being picked up-if it not even adjust accordingly until the tyre makes full contact, keeping in mind bimmers usually run with negative camber. otherwise just pick a number like 2.0 bar and see how it wears in a few months and adjust accordingly.

[Simon Motorsport]

Thats not a bad idea... yeah.. beemer usually have negativ camber and my one has extreme negative camber, also because of the lowering kit..

[Ayham]

For track I run 25-28psi upfront with 30-32psi in the rear, for street use I run 32psi all around. Try with 32psi and test what J said above...

1bar = 14.5psi

[the eldest boy]

For track I run 25-28psi upfront with 30-32psi in the rear, for street use I run 32psi all around. Try with 32psi and test what J said above...

1bar = 14.5psi

Ayham, you run 32psi on your 18's...would that be suitable for my 19's too? Mine are up at around 35, and i do somtimes feel that the car is slightly less grippy than i'd expect it to be, expecially as i have new Hankook S1 Evo's...

[Bruno]

i run 30psi all around

[the eldest boy]

i run 30psi all around

On 18s or 19s?

[Bruno]

19s

[Haissam]

i used to run 30-32 psi for the street.. for both 18s & 19s :)

[Nabil]

Guys u need to remember that those figues should change from summer to winter, as AIR expnads more in Summer than in winter

[jmeister]

Guys u need to remember that those figues should change from summer to winter, as AIR expnads more in Summer than in winter

no... the pressure u are measuring is only the differential pressure so it matters not whether its summer or winter-the pressure, which is actually the pressure difference, should remain constant. i wont get into the science about density etc, but tyre pressure is tyre pressure-pumping up when your vehicle loaded is a special case: here the main reason is to stop low frequency vibrations which will lead to a blow out at speed. thankfully, the lower the profile, the lower the chances are of that happening.

[Nabil]

??!

What i know for a fact that it does make a difference as streets becoem really hot in summer, after a few kms of driving your tires will become hotter and hnece the tire pressure will increase, hence you will need to note that while filling air in ur tubes!

[Bruno]

nabil has a point. psi increases in hot weather... run 30psi and be on the safe side.

[jmeister]

??!

What i know for a fact that it does make a difference as streets becoem really hot in summer, after a few kms of driving your tires will become hotter and hnece the tire pressure will increase, hence you will need to note that while filling air in ur tubes!

all the literature i have read say NEVER decrease tyre pressures when HOT...
tyre pressures are always checked when COLD.
summer/winter adjustment of tyre pressure SHOULD occur when u check your tyre pressure WEEKLY so that there is not a big jump in pressure.

[Nabil]

J, what u r saying is true, but i meant is for example, when COLD but in summer adjust to 32psi but in winter adjust to 35, cause in summer ur psi will jump to 35 after driving from 30, but in winter they will jump from 32 cause its colder, kapeesh?