How can I find out the best tyre pressures to run on a Porsche 911 with non standard wheels??

The fronts are 225/40/18s and the rears are 265/35/18s

Any ideas? :)

top

Start off with standard pressures, someone once told me that no matter what size wheels or tyres you fit, the pressures should stay the same, something to do with vehicle weight!

that can't be right coz it lists various wheel sizes on the car and they have different psi ratings! it just doesn't have the size of wheels I'm after! :)

...someone must be running these size tyres??

If you can get hold of a gauge then you can do what the race teams do and take their temperature. You'd need to go on a reasonably long run to get them warm, then check the temps on the inside, centre and outside of the tread.

If the inside and outside are hotter than the centre then the pressure is too low, if they are colder then it's too high.

If the outside is hotter than the middle, and the middle is hotter than the inside then you probably need more negative camber.

Regards
Matthew

edited to say 'sorry, i didn't read the qustion properly';)

[Edited by RRH - 1/31/2003 10:05:52 PM]

Ring the manufacturer, or contact the supplier that sold the wheel/tyre combination.

Good thinking Craig, i'll give that a go... :)