changing tire size
10-20-2005, 02:15 AM
#1
4th Gear
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changing tire size
I have a 996 Turbo. I'm thinking of changing my rear tires from 295/30/18 to 315/30/18. The overall diameter would increase by 0.5 inches. Without changing my front tires, would this have much effect on the safety features of the Porsche or the overall performance???
10-20-2005, 02:37 AM
#2
Burning Brakes
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I think it's been said that Porsche allows for a 4% variance in diameter for PSM, etc. Keep in mind that 10/32" worn down to 2/32" (legal limit) is 1/4" x 2 = 0.5 inches. If your fronts are bald and your rears are new that could be up to 1" difference which is right at the limit. Also, all diameters are nominal and vary from tire to tire. Further, your rears will be running more tire pressure than the fronts, so your rolling diameter will be proportionally more. You could very easily pass the limit which is probably something you don't want to be pushing anyway with AWD. You may wish to wait until you can replace all 4.
10-20-2005, 12:44 PM
#3
Rennlist Member
Originally Posted by zzzxxx
I have a 996 Turbo. I'm thinking of changing my rear tires from 295/30/18 to 315/30/18. The overall diameter would increase by 0.5 inches. Without changing my front tires, would this have much effect on the safety features of the Porsche or the overall performance???
