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Why go for the 17" front / 18" rear diameter wheel split when upgrading tires and wheels? Why not just keep all the wheel diameters the same. The SMZ and the new Corvette have it figured out. When doing a tire and wheel upgrade, if for the sake of this discussion tire width is kept constant, the same diameter wheel front and back will maintain the car's aptitude for under-steer or over-steer. Going to the 17/18 set up has a tendency to "tighten" the rear and "loosen" the front by eliminating sidewall flex in the rear relative to the front. This tightening will increase the car's tendency to over-steer. Conversely if you were to loosen the rear, you would promote under-steer. Other suspension adjustments, shocks, sway bars, springs, will effect the car's balance as well. But going to a 17"/18" wheel set up on a stock suspension will dial out some of the car's tendency for under-steer. I can personally verify this tech note from my car's set up. In my opinion, just what the doctor ordered. :-)

Taken fromhttp://www.georgiazclub.com/tips/ztech/300ttbasics.htm

Cheers. Bob.

yeah but isn't running different size wheels illegal, and it looks silly

shorty wrote:yeah but isn't running different size wheels illegal, and it looks silly

Two different rolling diameters would be illegal. Different size rims??? Look at the lambos ferarris and the porche they all got diffrent front to rear.

Problem is it wont really solve the stiffness problem of the standard suspension, although it is an interesting alternative to dialing out understeer/oversteer.

Just incase your wondering, i have tried it. My Gemini had 14" wheels on the front and 13" wheels on the back, it was suprisingly taily out of corners with moderate speed.

Nick-