I am new to these message boards, but have been driving my S2000 since 11/99. I love my S. Its the best car I have ever owned. She has been stock until last year, when the OEM rear tires were so gone that driving in the wet, felt like black ice. I replaced the rears with Kumho 712s Z 225 50 16s. (The salesman at discount tire talked me out of a wider width because that "was what the suspension was set up for." After reading posts here, I have learned several things. one of which is that a 225 width isn't always a 225 width. My OEM front tires will need replacing soon and my question is should I shift the Kumho's to the front and replace the rear with 255s or 265s vs upgrading to 18" wheels when the fronts wear out. The front tires are still holding well. My rear end will break loose before the front. Will changing to 18" wheels adversely affect the handling? I am planning on getting 3 piece Simmons custom made. They should be able calculate the suspension geometry, shouldn't they?

 

The reason your year end brakes loose is the mixture of tires and a much narrower tire than OE on the rear of the car. The Kumho tire is no way as good of a handling tires as the S02 that came on the car. The best set up with the Kumho is 205/55R16 front and 245/45R16 rear. You will get better all around handling with the same tire on all four corners.
If I can help in the future let me know. Obviously the salesman at Discount tire didn't know your car very well.
Thank you

Jim 800-428-8355-364