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Discussion Starter #1
we all know what the tire pressure suggestions are from the side of the door jam, with 48 psi rear and 44psi front being the maximum, but what pressure settings have people found the best to:
1. minimize understeer?
2. maximize "track" handling performance?
It seems that my front tires have more bite with about 35 psi vs. 44psi.
I know this varies with load, but what have others experienced?
 

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I also want to know how to convert psi to bar, since the tire pumps here are in bar and I have no idea how much to pump in.
 

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1.0 Bar = 14.7 PSI.

- Alps
 

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Interesting. Craig -is that based on track testing, gut feel, what?

I just upped my pressures from 36/40 to 44/48. Haven't had too much chance to drive it hard but I would say it feels a little more squirrely. That doesn't necc. mean less grip, of course - the opposite could be true. But if I don't get use to the firmer feel, I will go back to 36/40 - works real well and is very forgiving.
 

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I've been playing at the autocrosses now for a few months with mine. if you drive your car even close to the limits - 34/38 is NOT the way to go! You have a severe risk of the tire rolling off the rim at high speed hard turns - not pretty for your wheel, tire, or the rest of your car. My first autocross - I ran 38/40.... this was as low as I would rec going - the grip was nice - tire wear was severe - especially on the fronts. I have since been running 42/45 cold. Not as much wear - almost as much grip - virtually no chance of a tire removing itself. The Rec tire pressure is there for a reason - too low - you could lose a tire easily - too high (and when they heat up) you could have a blowout. stick within a few notches either way. Even the pro CCAers and autocrossers couldn't rec lowering too much (in normal situations - with smaller wheels and larger tires - they said it would be less likely to roll a tire - but with the extremes the M5 are set at - huge wheel, tiny tire - they didn't want to be responsible for sending me poor (or uneducated) information causing me to lose a wheel or worse. If there are any people out there - that have a real rec for autocrossing - someone that REALLY know's the answer - please pass it on - cause if I can lower the pressure some - with little risk to me or the Mach-5 - I would prefer the grip. (airport tarmac is real rough on tires to begin with!)

Please Help!!!!! (no offense to Craig - those settings are most likely good for 9/10ths of driving needs - it's the 1/10 you might hit at a driver's school, autocross or track event that I'm worried about!)

Cheers,
Sean
 
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