I need new tires, and the man at the local tire shop says I can run 275/40 on my stock GT/CS rim, not the brembos. 245 on it from the factory.

That sound right? Will it look like its too wide for the rim?

 

I think I've read a bunch of times on here that you don't want to go over 265 on that wheel. 255 would be more appropriate.

 

Im in the same boat..Looks like we can only get the 255(same ones that come with the brembo package) on the 8.5 rims..going for contentinal extreme tires

 

I thought that sounded kinda off. I've heard great things about Michelin pilot tires, anyone have them? Pirellis are ok but they cost too **** much haha

 

I always read on the forums of certain tires being too wide for wheels. For example, 285 should be the largest on a 9.5" rim. However a lot of tire shops say its fine to run a 305. So who the hell knows lol. I'm sure there's a guide somewhere

 

Yep....same boat here. Like to keep the CS rims with wider tires on the rear....

Tire rack is a good source for info.....but.....who knows. So much of the sizing really depends on how you drive the car....IMHO.... If you are not doing a lot of hard racing, a bit oversized might not be bad.

I would say mount it and see how it looks. Plus, if the shop says it is ok.........but we are all experts on the net too.....lol.

I will push mine to the largest I can on the rim.....always have on every car I have had.

 

You can always have your factory wheels widened as well.

 

This guy is running 275s on 8.5x19 inch wheels. https://themustangsource.com/f726/mo...012-gt-506355/

 

Never did post a closeup pic of them.

 

proper wheel width for a 275 is a 9" wheel. Ive seen people run 275's on 8" wheels and it bulges like crazy. I would feel more comfortable running a 265 max on a 8.5" wheel.

 

http://www.1010tires.com/tiresizecal...cde-gen-by-svr

Here's a calculator for tire Sizes. Just put in what size tire you would like to run and hit submit down the bottom. It will show you what size rim the tire is meant to be mounted on. Of course I've heard of people running 275's on 8in rims so I guess its really up to you lol

 

So I can run a 275/40/19 on my brembo wheels and it will be ok? Bout to order the hankook ventus evo k110 next week and was thinking about a staggered setup. 255/40 up front and 275/40 out back.

 

you can run wider tires on the 8.5" rims, but all you're going to get out of it is looks. The wheel will slide around on the extra side cushion and steal a lot of the performance on turns. It will feel mushy if you go as wide as 275s. Keep in mind, the Shelby wears 285s on 9.5" rims in the back. That's a full inch more. I would save my money and buy wider rims or have the ones you have now widened, but that's just me.

 

I would like to have them widened, but nobody does it anymore. Several places in the Austin TX area no longer does it, they fix curb rash sure, but not widening.

 

Just google wheel widening . There are places still doing it.

 

What's funny is a 285 is over an 1-1/2" wider then a 245 yet the rim they use is only an inch wider. I'd say if you will trade off a little cornering performance a 265 would be ok, especially if you kept the aspect ratio in check.

 

it's been pretty well covered above, but my suggestion is to stay with the tire manufacture's recommendations on wheel width

you can find that on TireRack ; look up the tires you are considering ; then look at the "specs" tab and it will show you the wheel width size range for that tire

from what I have seen, 255 is the widest that will have 8.5" in the range

 

You and I had the same thought. I wanted to keep my CS rims too. But the rim is just too small. I have the Michelin pilot sport tires and they are great! Tons of grip.

 

When I had the GT with the stock five spoke wheels I ran a 275/40 in the rear. Had no problems, little bulge, but it wasn't bad. I'll see if I can find a picture.

Edit, don't have one in the album or on my work computer.

 

This is a 275/40/ on the stock rim on my previous '07 GT Vert. Ran them for 30,000 with no issues. I believe that was an 8" rim but memory is getting old. I know it was not a 9" rim.