Currently it has factory stock wheels and tires in size 215/60/15 and I wanted to go to something with a wider contact patch because it just doesn't have enough ultimate grip for my driving style. Just wondered if I could go to something like 225/55/15 or 225/60/15 without messing up the speedo or tire rubs or not fitting the rim. I have a Grand Am GT that has 225/50/16 and it has sufficient grip. I have a gps to plot how much speed is off if I have to. Thanks for any info.I want to change the tire size of my 99 Grand Am SE?P225/50R16 91V is the standard tire for GT models, but that car uses a 16x6.5J wheel where your car has 15x6J wheels. Clearly you need new wheels to go to a +1 size like that.
Because your wheels are only 6 inches wide it really does limit your choices on upgrading to a different 15 inch tire size while still maintaining good roadholding and response. It is too narrow a rim to really go wider. And if you are going to have to buy new rims, why not just get 16's anyway?
Have you considered just getting a better tire in the OE size? There is a big difference between different tires within the same size in terms of how they grip the road. For example you may have some low-budget, generic S-speed rated passenger all-season P215/60R15 93S tire on there now. You could see a remarkable improvement in going to a high quality H-rated (P215/60R15 93H or 215/60R15 94H) Performance All-season tire that would provide improved grip and steering response while sticking with the factory size.
The Bridgestone Potenza 960AS Pole Position would be a tire that I think could provide you with considerable handling improvements while still retaining excellent all-season capability. For a little bit less money the Firestone Firehawk GT or Bridgestone Potenza G009 would also be an excellent option. Or the Yokohama H4s. Any of those will provide more than enough grip for safe and sane street use and I recommend them from personal experience in the order they are listed.
PS
I should add that shocks and struts contribute a great deal to the handling qualities of a vehicle and on a 99' there is a better than even chance you still have OE shocks and struts that are well past their prime. 50k miles is when they should be replaced according to industry guidelines.
KYB produce their AGX adjustable high-performance shocks and struts for this vehicle and these would certainly be worthwhile for getting the most out of those tires. The best tires in the world won't help you if the rest of the suspension isn't pulling its fair share of the load. Proper wheel alignment is also critically important. I know I can tell the difference in how my car handles if the front toe is even 0.10 degrees off where I like it.
ASE Certified Automotive Service Advisor working in the tire industry
