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Old 09-11-2007, 07:06 AM   #9
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Join Date: Jul 2007
Location: Sydney
Posts: 150
Thanks Jim

You haven't answered my question. Obviously you can't improve the handling balance by just increase the tyre pressure but it will help and it might be most cost effective way to do so.

As for taking driving conditions into consideration, Porsche obviously has done the homework for you already. They only have one recommendation for most continents and mostl driving conditions for standard size summer tyres which is 29psi at the front. In other words this is the most ideal tyre pressure for most driving condition regardless Potholes, Freeway expansion joints, paved vs unpaved, etc. So if Porsche didn't worry about using different pressures in different conditions why would you worry? Also, don't worry about "too low a pressure can cause rim damage more easily" because in this scenario we are trying to increase tyre pressure not decrease.

Having said that, however, it won't hurt to increase the front tyre pressure a little over the factory recommendation to improve understeer (not eliminate) Hence my question again to those who have actually tried various front tyre pressures what do you think is the most ideal front tyre pressure over the factory recommended 29psi?

Originally Posted by MNBoxster

Tire pressures are always measured COLD. You cannot eliminate or neutralize the Boxster's steering with Tire pressure alone, you can only make it more neutral. Alignmentspecs and perhaps even a change in some of the suspension hardware would be necessary to make it totally neutral.

I run a higher pressure than OEM spec as well, it gives the car better turn-in and it lowers the rolling resistance which aids acceleration and range (MPG).

But, there is no absolutely BEST Tire pressure. You need to take into account your driving conditions (consider Potholes, Freeway expansion joints, paved vs unpaved, etc.), your driving style, even the type of wheels you use (too low a pressure can cause rim damage more easily). It's best to experiment using an accurate Tire Gauge until you find a pressure that you think gives you the best ride and response...

Happy Motoring!... Jim'99

Last edited by panameras; 09-11-2007 at 07:12 AM.
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