Vader GT

I have to agree with Howarmat & D'Prived! The set up on his car looks the best on 18's. The 275's all around will work, but IMO does not look as tough as the staggered option. Good luck!!

captbill51

I have an '11 with Brembo brakes. this eliminates many wheels. I like the staggered look so I went with SVE.



255 / 275 on 18 inch wheels. The brembo's really fill the front hoop. This car came with 19's but I like the 18 look better, and have more tire choices

mayo

275 seems like overkill on the fronts unless your going to the track, the 255 is a better option imo. The back in a 275 would be good, but a 285 would be better and yes it does have more sidewall according to the tire calc.
275/40/18 sidewall comes in at 4.33in, while the 285 is 4.48in...not much, but every little bit helps when you eat a pothole brother! More contact patch = more grip as well, really a no brainer to me. 285 all day is the choice...unless your one of those crazy people that get 295/45/18 in the rear

jrockgts197

I agree that the 255 front 285 rear staggered option looks the best. I struggled with my decision for weeks before I pulled the trigger on my setup. In the end, the ability to rotate the tires was more important to me than the staggered look and AM had the 275 at a killer price, so that was a no brainer for me. I ended up going with the 99-04 offset rims which makes the tires appear larger than they are because they sit farther out in the fender. It's really personal preference and I chose a little more practicality over a little better looks. I think the OP was more concerned about the sidewall comparison, which is almost dead even.

Norm Peterson

Here's a near head-on shot of mine. 255/45 Goodyear Asymmetrics on the FRPP 1895 wheels. Yes, that was the front tire/wheel package on at least the 2008 GT500.

It's the package that I tried to get the dealership to package for my GT (two sets of GT500 fronts) when I ordered the car, but they wouldn't go for it.

With anything less powerful than a tweaked 4.6 (meaning more than just a cold air & tune), there isn't much reason for going wider out back for strictly performance-based reasons. Appearance is something else, and something I'll (mostly) stay out of.

There is VERY LITTLE sidewall bulge or shape . . . and sharp cornering response. Maybe I'll put them back on today if I get too pissed doing taxes (Asymmetrics or any other summer tire comes off during the winter).



FWIW, there isn't a whole lot of visual difference between 255/45 and 275/40 when they're both mounted on 9.5" wide wheels. Nowhere near what 20mm worth of size difference might lead you to expect. I'm not making this up; there is a reason based on how tires are measured.


Here's a side-on shot (hope it works this time). Stock ride height.






Norm

05 Mustang

+1

same sizes that come on the GT500 from the factory

Norm Peterson

Don't forget that OP's car is a 4.0, which doesn't have the acceleration traction requirements of a GT (let alone a GT500).

Unless "creating the image" is the single, absolutely overriding consideration, the ability to directly rotate the tires is really going to be worth more in his case.


Norm

Jasoon

I hadn't considered 275/40's until I stumbled into LRS... Such a wide tire, though... almost 11 inches? And, the price i've been quoted locally for 275's is less than the other sizes, at least so far... still need to call around and decide to buy tires locally and order the rims, or order as a package. The nearest FRPP dealer is 200 miles away.

Define win: looks, performance, or overall ride quality?

Norm Peterson

I'd guess that there isn't likely to be much difference in ride quality - although the 255/45 has a little taller sidewall, the 275/40 has slightly more sidewall curvature when both sizes are mounted on 9.5" wide wheels. I see it being pretty close to a wash, as long as both tires are the same mfr and model, and a couple psi change in inflation pressure making more difference.

The 255/45 stretches out a little when you mount it on a 9.5" wheel, so your comparison should maybe be between 275/40 and imagining what 265/43's would look like (if anybody actually made such a size), and perhaps you could use this to help with your own appearance-based considerations. Neither size is going to have much sidewall bulge (or "belly"). And the 275/40 would normally have the wider tread (you'd have to look this up for each specific tire).

The 275/40 is a little shorter, so you could expect your acceleration to be just a tiny bit better with them even though they likely do weigh a little more than the 255/45's. But it won't be enough better to honestly SOTP-feel the difference, just enough for electronic dragstrip or possibly autocross timing to find for you.


Norm

partsbill

285/40/18 rears on 18x10 rims offset +45mm (1.8") backspacing 7.2" (184mm)
245/40/18 fronts on 18x9 rims offset +36mm (1.42") backspacing 6.32" (160mm)
tires fit flush.