I know that when it comes to what looks good on a car, a wider wheel and tire looks better thank a thinner one, but at some point wouldn't the width of the tire becomes counter productive? By that I mean as a wheel and tire gets wider, they get heavier, which requires more power to produce the same outcome. What I'm wondering is how wide of a tire would be needed per given horsepower or torque. The CT230 sat on 265/35-18s when it was setting time attack records. Is anything more than that just overkill? sorry if this was mentioned before, I tried searching and couldn't come up with anything...

 

It depends what you are doing with them. Most people run 265s and that is plenty for them, or maybe 275s. Really big track ****** run 285s. if you are running a stock turbo I wouldn't go with anything over 265 unless it's for looks.

the way to loose more weight is the wheels you run. Usually the cheaper the wheels, the heavier they get.

 

It all depends on the use of the car and lot of other things like suspension set-up and etc. What do you plan to do with your car?

 

Spirited street driving for the most part with a couple track days a year. Really I don't want super wide wheels if there is not a difference from ones that aren't as wide. I mean isn't there a point where you achieve maximum grip for say 450 hp and then anything wider is just extra, meaning more resistance?

 

Yes, at some point, more wheel and tire is counter-productive. But with a 3400# car, that point is way beyond what you'll ever get to fit.

 

It depends on the tire compound at that point. You plan on running an all season or something that has grip?

A 265/275 in a nice summer tire will suit you nicely I would think.

 

Another thing to think about with tire performance is tire temperatures. If you run a skinny tire on a big heavy car on the track, the tires will get too hot and get greasy and not grip well. If you run wider tires than are needed on a small light car you wont get the tires up to proper operating temperature and they wont grip well.

Of course all of this doesn't matter much with daily driving.

 

I'd personally stick with a 265 or 275.

 

As a track *****, I run 285/35-18's on 18x10.5" wheels. Diameter is the same as stock but because the width is 2" wider it gets really dicey on fiting them inside the wheel wells. You will need adjustable rear control arms to get -2.0 to -2.5* camber in the rear and probably have to run at least -2.5* camber in the front which means aftermarket coilovers or larger offset camber bolts. Fenders had to be rolled in the rear and plastic wheel well pieces had to be heat gunned for clearance.

I would probably stay with the 265/275 sizes unless you are willing to go through all the extra work to fit the 285's and get maximum contact patch. Even with my MR on the stock turbo at 400 crank hp and losing some straightline performance, most road courses will still give you enough benefit in the turns to compensate for that and then some. Once you are in the 600+ crank HP range, the widest tires possible are pretty much required to stay competitive.

Going with lower profile 19's can help response with the shorter sidewalls, but bumps will be more severe and if your roads are bad you have a higher risk of bending/cracking a wheel. Tires also start to get harder to find in all the sizes you want to use where a diameter similar to stock is desired.

Hope that helps.

 

Also remember that compound is more important than width. So if you want grip, that's what you should look at first.

 

I've had this conversation with a lot of people and I'm still at a loss.

FWIW, Sierra Sierra, AMS, and all the fast stateside evo's mostly use 285/30/18. I know some other stuff, but I'm not going to get into it because its a little off topic but I really question when you have a car that weighs well over 3000lbs and 600hp, how could you not benefit from a 315 vs a 285?

To answer my own question I'd say that of course you will get more grip with the larger tire, but are you sacrificing the balance of the car? Reducing rotating mass helps more with agility than anything else. The answer, I really don't know.

All I'd have to do to run a 315 in my car is get a new rear trailing arm and possibly 6" springs, but then again I'm not running race compound, probably not worth it for me although the car will have 600whp......

In the end you'd really just have to test it for yourself. However, budgeting for that is problematic...

 

Indeed, forgot to mention that.

Hankook R-S3 are about the stickiest street tires you can get your hands on and would help quite a bit. Only drawback is that they are a bit weaker in the wet handling/hydroplaning department but such is life when you want an extreme performance summer tire.

 

Completely agree with you, Chris, on the R-S3s. Reminded me of old Victoracers on dry pavement. What would you suggest for rainy days on the street and/or in STU?