I want to get some 265's.

1) How will it affect performance to have 265's on all four wheels? For some reason, something tells me that performance would be better with 235's on the front and 265's on the back.

2) How wide does my wheel have to be for the 265's to not look stupid? I mean, how wide should the wheel be so the tire doesn't hang over the edge of the wheel?

3) Are these good tires: BFGoodrich g-Force Sport? I'm not looking for "the best" or even extremely high end. I'm on a budget and those are $150 each for 265's...best price I've found by far.

Thanks for the help!

 

1.) Since these cars are closer to a 50%/50% weight distribution, I think the same size tire all the way around would probably give you the best cornering ability.
2.) Having a tire that is an inch wider than the rim is a good thing if you ever plan to make a parking mistake near a curb stone. When the rubber and the rim are flush, just one minor touch is major damage to your rim. My brother had to replace all four rims on his wife's car after she banged all four of them up, and then finally bent one hitting the curb stone. Better get curb feelers for flush-fit tires/rims.
3.) I'm paying $100 each for my tires (255/50ZR-17). I believe this is the least expensive option, and with 10� wide rubber on a 17"x8" rim, I have an inch of "curb bumper".
4.) The stock tire diameter on your GT is:
23.5mm * 1/2.54 inches/mm * 55% * 2 sidewalls + 17 inches = 27.2�
5.) If you use the economical size 255s, then you would have the following:
25.5mm * 1/2.54 inches/mm * 50% * 2 sidewalls + 17 inches = 27.0�
At 60 MPH Indicated, you would be traveling 60 * 27.0 / 27.2 = 59.6 MPH Actual
This is pretty close to spot-on.
6.) If you do go with 265s, then you would have the following:
26.5mm * 1/2.54 inches/mm * 45% * 2 sidewalls + 17 inches = 26.4�
At 60 MPH Indicated, you would be traveling 60 * 26.4 / 27.2 = 58.2 MPH Actual
26.5mm * 1/2.54 inches/mm * 50% * 2 sidewalls + 17 inches = 27.4�
At 60 MPH Indicated, you would be traveling 60 * 27.4 / 27.2 = 60.4 MPH Actual
Also, this is pretty close to spot-on.

 

Wow man, great post. I especially like the speed calculations that take the width/height ratio into account. Until I read that post, I didn't even give the width/height ratio any thought.

265 mm = 10.43 in, thus with 9" wide rims, I'd have 0.71 in of "curb bumper"...that sounds good to me.

What kind of tires are you using and where did you get them? I wonder how much more they would be for 18" diameter and 265 mm width.

Thanks.

 

I built this spreadsheet when I was in the market for wheels/tires a few months ago. Comes in handy for quickly comparing sizes.

 

Hi Again,
The 255 tire is from Les Schwab, and is described as follows:
Product Code: 01410750 255/50ZR-17 RH06 All Season Blackwall $100.83
I will have to call and find out the name of the tire.