tyre pressure investigation

[yiano]

ive been experimenting with tyre pressures on my cooper s for a while now ive both the standard 17 inch s pokes with pirelli tyres and an aftermarket set of 17 inch with dunlop sp 9000 tyres.

mini reckons 33 psi all round ,so i began from there as i have eibach springs and i felt the ride too soft. using a digital gauge i recorded about 29 psi all round , so i reset to factory 33 psi ,not enough grip in my opinion and a tendancy to understeer so up the pressure again to 38 psi front and 40 psi rear this has increased grip on the front and reduced the ammount the back steps out during over steer, i feel its at optimum the balance of the car now feels quite controlled 38 psi front and 40 psi rear seems to work

if anyone has found better settings please let me know !

[pocketrocketowner]

2-3 pounds higher in the rear works best for the dunlop run flats. I try to run them in the 35 and 37 range HOT all the time so what I do for consistency is when I come off the track, I bleed them down to that pressure.
Cold start temps are a bit of a guess cuz of the weather and the track itself. Anyways, you are on the right track.

[Tracie]

Isn't that a little high??

[pocketrocketowner]

Quote: Originally Posted by Tracie

Isn't that a little high??

Not for the track on 'street' tires, not at all.