Tire too wide?

[egzlilgituarboy9]

Im look to get some new tires pretty soon and I currently have the continental extreme contact 275/40/17 in rota rb's 9.5 wide I was wondering if I could fit a 315 tire in the 9.5 wide rim because I have a friend who's got a 2011 gt500 cobra and says he's got a 315 on a 9.5 inch rim anyone done this? Or can anyone suggest a good tire for me?

Edited October 5, 2011 by egzlilgituarboy9

[JMortensen]

There's a bit of room for discussion here. Just because you can put a 315 on a 9.5" rim doesn't mean that you should. Ideally the rim width would be a little larger than the tread width (315 is the section width [widest part of the tire], not the tread width). On the other hand, sometimes putting more tire under the car will make it handle better just by virtue of having more rubber available, even if the tire would perform better on a wider rim. If you want the car to turn, putting a tire that is too wide on the rim will make transitions feel sloppy. I ran a 250mm wide slick width on an 8" rim, and you could really feel the tire flopping over before the car took a set. It was a lot faster than a 205 on a 7" rim that fit perfectly though. That 250mm tire should have been on a 10" rim according to the manufacturer. If you really want to run a 315, ideally you would get a rim that fit a 315 best. If you have to run that rim, then you can figure out how much tire floppiness you want to deal with and take it from there. If you want a suggestion for how to get the most out of the tire that you want to run, I'd say find the tire you want, look up the tread width, and buy it .5" narrower than the rim.

Edited October 5, 2011 by JMortensen

[Driven5]

Well, no manufacturer recommends less than a 10.5" minimum wheel width. Another factor is rubber compound. If there is a specific tire you want to run, a 315 tire might provide some additional grip over a 275...However all of that goes out the window when you start looking at two totally different tires with two totally different rubber compounds. It's very possible for a 275 tire in a stickier compound to provide more grip than a 315 tire in an inferior compound, even when both are on ideal width rims. Consider too there is appreciably better availability of 275mm tires than 315 tires. While it's probably able to be made to fit, I personally I wouldn't bother trying to squeeze a 315 tire onto a 9.5 wheel unless I was specifically in a racing class with wheel width limitations.

 

Suggesting a good tire make/model depends heavily on your intended use(s) for the car, and what compromises you're willing to make in regards to the tires to achieve those goals.

Edited October 5, 2011 by Driven5