I'm thinking of buying new wheels and tires. I want to go to a lower profile tire while I'm at it but I want to keep the wheelwells filled the way they are now. Stock is a 45 profile tire. If I just buy a lower profile 35 sidewall tire for 18-inch wheels, the outside diameter of the wheel will be smaller. I know this would be good for acceleration but I'm afraid I wouldn't like the way it would look unless I lowered the suspension too, and even then, probably not. Can anyone tell me approximately the difference between the outside diameter of a 45 profile 18-inch tire and a 35 profile 18-inch tire? Is there a certain profile tire that I could put on a 19-inch wheel to get the same rollout? Basically, what I'm asking is if you had the stoch wheel and tire off the GTS and mounted some different profile tires on a 19-inch wheel and sat them on the ground next to eachother, which profile tire on the 19-inch wheel would make it the same height as the stock GTS wheel and tire?

 

45 and 35 are percentages. Not measurements.

For example, if you have 215/45/18s on the stock car, your "profile" is 96.75mm. If you bought a 215/35 tire, the "profile" would be 75.25mm - these tires would make your wheel/tire combo nearly 2 inches smaller than the stocks (because of the shorter sidewall).

Continuing the example, if you wanted a 225-width tire, you'd need a 43 profile - which doesn't exist. You could conceiveably buy a 245/40 tire and it would be roughly the same sidewall size as stock.

Might want to call up Tire Rack and discuss your needs with them. They can help you figure out what's best overall.

 

Yup... tire sizes are really the strangest measurement I know of. The full measurement includes a dimension measured in inches, a dimension measured in millimeters and a third dimension which is given as a percentage.

I'd like to know who the joker was came up with that idea.