Correct tire pressure for the 930
02-13-2010, 09:30 AM
#16
Three Wheelin'
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Well mine's a euro model, and the rear tire contact patch story seems consistent with what I've seen and experienced, although I said "cupped" bow is probably a better description of the phenomena. I haven't tried to run the fronts that low before. As cold as it outside in FL right now if I check pressures they may be close though ;-)
02-13-2010, 10:50 AM
#17
Burning Brakes
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In North America it says 29/36 while in Euope the same car is 29/44. A Pirelli Tech explained it to me once.
In Europe the cars spent a significant amount of time at high speed on the autobahn. When running at such high speeds, the carcass of a wide low profile radial will bow out in the middle due to centrifugal forces. The higher rear pressure helps keep the tread face flat.
He then went on to explain that all those general tire books are outdated. When the Popular Mechanic's guide shows that tire wear in the center is caused by over inflation, they are not referring to modern high performance low profile radial tire. In this case it's actually caused by under inflation.
In Europe the cars spent a significant amount of time at high speed on the autobahn. When running at such high speeds, the carcass of a wide low profile radial will bow out in the middle due to centrifugal forces. The higher rear pressure helps keep the tread face flat.
He then went on to explain that all those general tire books are outdated. When the Popular Mechanic's guide shows that tire wear in the center is caused by over inflation, they are not referring to modern high performance low profile radial tire. In this case it's actually caused by under inflation.
02-13-2010, 01:41 PM
#18
Sorry I should add that I never run the front that low either. I usually run about 2-4 lbs difference front to rear. Usually 32-36 or so for the street.
On the track I run about 37-38 hot all around. I'm using Toyo R888 R-Comps 225/295 on 9/11x18. I run the same tires on the street.
On the track I run about 37-38 hot all around. I'm using Toyo R888 R-Comps 225/295 on 9/11x18. I run the same tires on the street.
