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      03-06-2011, 07:42 PM   #15
kmarei
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Drives: 2018 Audi RS5 coupe
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Location: Reston, VA

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Quote:
Originally Posted by Lotus7 View Post
Anyone who has ever raced on a track or participated in an autocross will usually wind up with pressures substantially above the factory rec. settings if they want any chance of being competitive.

This is well documented in race oriented magazines such as "Grassroots Motorsports" where they routinely do tire tests on various chassis, as well as every basic book on how to improve your cars handling for competitive purposes. "Grassroots Motorsports" last comprehensive test on a Miata wound up using pressures in the 41 to 46 psi range for a car that has a factory rec. pressure of 32 psi. This was for a autocross at the TireRack's test track in Indiana.

Personally, EVERY street car and race car I’ve driven, road raced or autocrossed from my full race SCCA A-Modified Corvette and Lotus S-1 to my wife’s Subaru wagon has had significantly higher grip as well as better transient response at a tire pressure higher than the factory recommended settings. Sometimes it’s only a few psi more and sometimes it’s as much as 10 psi. I’m speaking about ultimate dry road grip independent of ride quality.
not sure how anything to do with taking a car on a track has any relevance a SUV driven on the road
plus 10psi more means if you are driving on a hot day on hot asphalt, your tires could increase in psi due to heat, above the 51max psi
i've seen an 8psi increase from the start of a journey and 30 minutes later after driving around 65-70mph on a highway
8psi increase if you set your tires at 46 means you are at 54psi
that's 3psi more than the maximum tire pressure set by the manufacturer

i don't feel i can trust your judgement in a car that carries my entire family
you can put what makes you feel more racey (in an suv)
but the recommended psi is put there for a reason
you wanna go higher be my guest

and that's not even taking into account the shape of the contact patch or how uneven the wear is going to be on your 46psi tires.

not everything learnt on the track is relevant in the real world.
we don't change our tires after 1 or 2 track events
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