Tire vs. Wheel Width

[fastbacker]

I've always wondered this. On average, how much wider should the tire be over the wheel width - for a street car? I know it would vary with the tires shape but I'm just looking for an ideal average.

A popular example would be the guys running 11"(279.4mm) rear wheels with 315mm tires. The difference would be 35.6mm (1.4") or about 12.7% difference. Is this about the average?

Thanks-
Craig Backer

[masraum]

generally if you look up the tire on the manufacturers website it'll give a range of wheel sizes that the tire should fit.

For instance, a 195 50 15 may say that it fit's 5.5"--7" wide wheels. If possible you want that tire on a 6.5" or 7" wheel for optimal handling.

When you put the tire on a narrow wheel it causes the carcass of the tire to pinch which distorts the shape of the tire and allows for more flex under lateral loads. Wider wheel with narrower tire will give less flex and better handling to a point. You can get too large too.

[RarlyL8]

My personal rule of thumb is to use a tire tread width that is the same as the wheel total width.

For example, an 11" wide wheel has total wheel width of ~12".
305mm is exactly 12.0" so that is where I would start. Tire wall hieght will play into how you adjust that measurement for your application.

You must also consider that each tire manufacturer has their own ruler. A 295 Yokohama is the same width as a 315 Pirelli.