This is my first post and I wanted to get your everyones opinion. I just purchased 20x8.5 (front) and 20x10 (rear) Anthracite Bullit Wheels from American Muscle for my Tungsten 06 GT. Their web site recommends 255/35/20 for the fronts and 285/30/20 for the rears. Does this seem right? I want to stay around the factory tire height, but dont want the rear tires to look smaller than the front tires. Any other recommendations? I've also seen people go with 275/35/20 for the rears versus the 285/30/20. Which do you guys prefer for the front and rears. Any help would be appreciated as I come from the world of truck tires where everything is a lot bigger. Thanks in advance.

 

I did the exact same set up and did 255/35/20 front and 275/35/20 rear, but my car is lowered, check out the pics in the "show us your wheels " post I could not be happier with the look and fit

 

255/35-20 is as close as you can get to the stock tire height.

Stock tire height = 27.2 - 27.3"
255/35-20 height = 27.0"
285/30-20 height = 26.7"
275/35-20 height = 27.6"

If you want to play around, click on this Tire Calculator. Put what you are getting for the front in the left "stock tire", and what you want to get for the rear in the right "new tire". It'll overlap the tires showing you the difference and tell you how far off your speedo will read. But, I don't know if our speedos are set by the front tire height? or the rear tire height?

Either way you go for the rear will make you a little off from the front, but I don't think either will be noticable unless you went out with a ruler. I would go with the 275/35/20's for the rear because it is .6" more in diameter, so that will fill the wheel well gap in a little over 1/4".

 

Thanks 06TUNGVERTGT and 89Trooper for your advice . I originally wanted the American Racing Shelby Razors but after seeing 06TUNGVERTGT pics I knew I needed to get the bullitts. After reading 89Trooper's post, I think I will be going with 255/35/20 in the front and 275/35/20 in the rear. Once I get them mounted I will post pics. If anybody else has an opinion, please keep posting as Im sure I am not the only one with this situation.

 

Most people get the 30 series in the back because as you stretch the tire out wider 275 or 285 it brings it down a little bit, I dont think that chart 89trooper had is too accurate. Thats why you see most everyone with those tires on mustang with 35 front and 30 rear.

i put 285 in the rear and 245 in the front. No rubbing or any issues. its also lowered 1.5"

 

True, that Tire Calculator is theoretical and doesn't take the width of the rim into consideration, but it's pretty darn close.

So, in this case, the rear rims are 10".

A 285mm wide tire is 11.22" wide at the tread, and a 275mm wide tire is 10.86" wide at the tread.

A 285/30 has a 85.5mm (3.37") tall sidewall.
A 275/35 has a 96.3mm (3.79") tall sidewall.

Neither one of those tires will need to be stretched that much to fit onto a 10" rim, so either way you go, I think you'll be fine.

I'm lowered 7/8" up front and 1 1/4" in the rear, and I have 255/45-18 on the front and back on 18x9" rims so I can rotate front to back at every oil change.

No, the reason that people get "30 series" in the back is because the second number is the aspect ratio, or how tall the sidewall is in relation to the width. If you go wider in the back, of course you have to have a smaller aspect ratio or the tire would be too tall.

That's why 255/45-18's in the front and 285/40-18's in the back is a perfect match. 45% of 255 is the same as 40% of 285 (within 1mm).

When you go to 20's, you won't get a perfect match like that... so you have to choose whether you want the rear tire a tad shorter, or a tad taller. Like I said, both are so close you won't see it unless you take a tape measure to the car...

 

With 275/35/20 will the tire look too stretched out?

 

No... Your rear rims will be 10" wide, (or 254mm wide). 275's or 285's will fit just fine. People take stock 18" rims and put 255's on them, and stock rims are 18x8" (203mm wide).

Call Mustang Tuning (American Muscle) and talk to them (it's toll free 1-888-782-6448). Ask why they recommend the 285/30-20 tires. Also ask them how they think a 275/35-20 would look. They may have a specific reason for saying to get the 285's. Or it may just be the closest tire they can find to the stock height.

They may help you choose one way or the other.

Let me know what you finally choose and post pics!

 

Thanks 89Trooper! Will do!