if you take the higher ramp aggresively...left front tire will loss pressure faster than the rest...sometimes i've got 29 psi on the left front tire

 

I usually run 36/36 on the street, I'm trying 34 all around right now. At autocrosses, I usually run 40 all around.

 

37 front 35 rear, a little better response than the recommended 32. Often manufactures list presures lower (32) because it increases ride quality (if you like soft and quite). I run more in the front to help tame the Oversteer characteristics of the car at it's limits. YMMV

With modern hi performace tires, you have more leway in the presures settings. The casings are very ridgid, changing presures do not have much effect on the contact patch shape. More effect is noticed in side wall ridgidity.

andy

 

38 Front
34 Rear

 

Interesting thread because this last weekend I checked the pressure after not driving the car for a week. It had just come back from the dealer and I was on a motorcycle trip. It had 34psi all around so I lowered it to 32psi. Took a trip through the Green Mountains of Vermont and I've never had more slides. I'm going back to 34psi. I'm puzzled though since I would think that a higher pressure would make the car more prone to sliding.

 

After driving on the freeway for about 25 minutes, my tire pressure is at 34psi on all 4 corners. I guess this is the hot termperature, so what would the original cold tire temperature be? say ... in the neighborhood of 29-31 maybe?

I find 34 all around nice for everyday driving, and not too bad on the track.

BTW, does lower pressure shortens or lengthens the tire's life?

 

32 Front
34 Rear

 

Street: 36/36
Track: 37/38
I'm getting great grip and balnce, with even tread wear.

As for "manufacturer recommendations":
1) Clearly, the pressure recommended by a vehicle manufacturer can, at best, only be considered authoritative for the OEM tires. If you go to a different tire, why assume that the owner's manual still applies? Also, some cars are available with different wheel/tire combos as a factory option; but does the owner's manual distinguish between these fundamentally different setups? In most cases, I suspect not.
2) I think vehicle manufacturers tend to recommend lower pressures than what their tire suppliers would consider optimal. For example, there was great hullabahoo about the different recommendations from Ford and Firestone on those Explorer tires that were suffering delamination. Another example: my '91 Honda CRX-Si manual called out 28psi (!!), but I found best results (even wear, nice ride, good handling) running 32-34 psi.

So why do car manufacturers like low pressures? After all, proper (higher) pressures can improve tread life, ride comfort, and fuel mileage, not to mention decrease road noise! Well, if I were to guess, I'd suspect a lower-pressure tire is less likely to have a blowout when hitting a sharp bump. Remember, blowouts are traumatic: often, people who experience a blowout at speed are sufficiently shaken up afterward that they simply get rid of the car and buy something completely different; they don't stop to think about the role of the tires. So spec'ing lower pressures may be a way to deal with the realities of poor road conditions and potential loss of customers who are unnerved by a blowout.

So, anyway, as others have said, use the owner's manual to get "in the ballpark", then adjust as needed to get the results you're after.

 

I always stay with 34/34 on the street and have had excellent grip, reasonable tread wear, and a fairly comfortable ride.

At a driver's school this past summer at Watkins Glen, I started at the recommended 40/40 and found the car to be very loose. I changed the pressures down to 34/34 after that first run and found that I had a lot more confidence in all of the corners.

Coming off the track after a 30 minute run, the pressures were sitting around 42-44 psi.

I am still running on those same S02's and feel that the most important thing is to check them often and keep them even left to right.

 

[QUOTE]Originally posted by honda_s2k
[B]I always stay with 34/34 on the street and have had excellent grip, reasonable tread wear, and a fairly comfortable ride.
Coming off the track after a 30 minute run, the pressures were sitting around 42-44 psi.