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RandallNeighbour · 03-19-2006, 03:40 PM

I have aftermarket wheels (ROH) on my boxster. When I bought the car nearly 2 years ago, the Tire Rack guy recommended that I go with 255/40/ZR17 on the back and 225/40/ZR17's on the front. I am now experiencing some cupping on the front tires, and have never been able to get them properly balanced.

My rim sizes are 8.5 x 17 on the rears and 7.5 on the fronts.

I'd love to upgrade to 18's (even though Porsche doesn't recommend it) but I just don't have the cash right now. So I must put more rubber on these rims for another year or so.

Anyone willing to tell me the correct tire size for these rims? I don't want cupping from too wide a tire again, and I think that's what happened, but I'm not sure.

03-19-2006, 03:40 PM	#1
RandallNeighbour Registered User Join Date: Jul 2004 Location: Houston, Texas Posts: 7,243	Correct Tire Size I have aftermarket wheels (ROH) on my boxster. When I bought the car nearly 2 years ago, the Tire Rack guy recommended that I go with 255/40/ZR17 on the back and 225/40/ZR17's on the front. I am now experiencing some cupping on the front tires, and have never been able to get them properly balanced. My rim sizes are 8.5 x 17 on the rears and 7.5 on the fronts. I'd love to upgrade to 18's (even though Porsche doesn't recommend it) but I just don't have the cash right now. So I must put more rubber on these rims for another year or so. Anyone willing to tell me the correct tire size for these rims? I don't want cupping from too wide a tire again, and I think that's what happened, but I'm not sure.