I am looking at a set of wheels, 17x9 in front and 17x10.5 in the rear. The website suggests that I get 275/40R17s all around. Shouldn't I have a bigger tire for the rear? Something like 285/40 or even 315/35? Any suggestions?

 

Check the stickeys at the top..

275 are perfect for a 9" wide wheel. The sidewall is nice and flat. Not bulged in anyway. (I have GSD3's so they fit over the wheel rim anyway). I have 285's on my 10" wide rears. They're fine too, but the tire is a smidge too thin. You can do 315's on a 10.5 fine. 295's or 305 would fit better on a 10.5, IMO.

 

ok so 295 or 305 would be good for the 10.5" wheel, but what about the sidewall? I know that the sidewall number is the percentage of the width of the tire, so if I got a bigger witdh tire, should I get a smaller sidewall to make the tire thickness the same in the back as it is the front? (I.E. 275/40 = 305/35?)

 

^ check the stickies up top.
http://web.camaross.com/forums/showthread.php?t=312442

They will give you diameter info according to tire size..

 

They don't make 17's in 295 or 305.

A 315/35-17 is exactly the same outside diameter as a 275/40-17.