Increased tyre pressure

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Fri 28 Sep 2001 18:09
Increased tyre pressure - DanJ_uk
I know there have been a few issues with swearing on this forum recently so I will be very careful and say "blimming heck!". After reading earlier posts re increasing tyre pressure to improve handling I read the Michelin site and increased my front tyre pressure from 31 to 33 and the back from 30 to 38 (didn't dare go quite as far as Michelin were suggesting!) on a late plate 1.8 Cavalier to see the effects. The difference is nothing short of astounding - I found the car understeered to an extent one could possibly even call dangerous (Hired Vectras I have had have been worse!) and I have always been very meticulous with tyre pressures as per the handbook but increasing the back tyres a few PSI has made the car handle not quite like a dream but not far off it, the steering is also much lighter now as well.

If the drive is so much more improved (as I bet it would be on many other FWD cars) why do manufacturers quote such low pressures?
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Fri 28 Sep 2001 20:52
Re: Increased tyre pressure - Mike Harvey
Dan, the rule when I went racing (as a mechanic) in the 70's was get the tyre pressures right first, then adjust the damping for turn in. Softening the front gives more grip, and therefore better turn in, softening the rear gives more understeer. (and vice versa) There starts the balancing tricks for the whole of practice. Once Driver is not moaning quite so much, have another go at the tyre pressures for a final tweak. Of course softening both front and back too much inevitably leads to roll oversteer, and back to square one. Never quite get it right, and it's ALWAYS the mechanics fault!
Regards
Mike
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Fri 28 Sep 2001 20:56
Re: Increased tyre pressure - Andrew Hamilton
Thanks for the explanation. Explains my van handling on corners when unloaded!
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