My Stang came with 235 50 18 all around and I want to get a wider SVT look so i want to go to a 275 45 18 on just the rear.....will having two different size tires mess something up?

 

It should be close enough. Do a google search for tire size calculators. If the overall height is with in about 1/2 inch or so I wouldn't worry about it.

 

I plan on going with 255/45R18's all the way around with .25" wheel spacers for a slightly wider stance. (Also plan on a 1" drop)

The recommended rim width for the stock 235/50R18 tires is 6.5 - 8.5 inches.

The recommended rim width for the 255/45R18 tires is 8 - 9.5 inches. Still within .5 inches.

The recommended rim width for 275/40R18's is 9 - 11 inches. Out by .5 inches.

The stock 18" wheels may not be wide enough for 275 series tires. The tires will probably balloon out. You may want to test fit one on the stock wheel to see how it looks first or if there may be a width problem.

A 255/45R18 or a 275/40R18 should be close enough to the stock diameter so that your speedometer isn't thrown off very much. If you go with a 275/45 aspect ratio, the tire will fill the rear wheel well up since it would be slightly taller than a 40 series, but it would also throw off your speedo more.

http://www.1010tires.com/TireSizeCal...?action=submit

Hope this helps.

 

275's are too wide to fit the stock 8" wide wheel correctly. You could put them on there but they won't work the best.

 

A 245 tire is as wide as you will want to go with a 8" wide wheel. A 8" wide wheel is 202mm while you are trying to fit a 275mm tire on it. That mean over 36mm per side will be bulging out the sides, which is over 1.5". You will need at a minimum a 9" wide wheel to accomodate a 275 tire. Even that wouldn't be optimum, 9.5" would be.

Dave

 

Thanks for the info guys