different rally backspacing

[bustedknuckles]

does anyone know the difference in the back spacing between the 15x8 and the 15x7.ralley wheels? im wanting 235/60/15 on the front and 275/60/15 on the rear. do you think i will have any problem with the 275's on the rear or should i go with the 255's ? mine are 15x7's . with 245 on the rear and 205/65 on the front. they were on the car when i bought it. pros or cons gimme so advice, thanks

 

[Ribbedroof]

All the GM factory ralleys I've ever had in 15x7 were the same 4" backspace as the 8".

255s will have plenty of clearance, 275s should be fine, although some folks don't care to put them on a 7" wheel.