2008 GMC Sierra ext cab 4x4 has 265 70 r 17
235/65/R16
Open the drivers door and look at the door jam and you will see a sticker with that info. on it
15 inch sould be the stock rims and 31 should be the norm for the tire size
235/75/r15
my stock ones are 265/75/r16
This matters if a 1500, 2500, or 3500...
if its a 16 in wheel and 1988-1998 then biggest is a 285/75 R16
There is a sticker on the drivers side door that will tell you.
Listed in the owner's manual and on the driver's door post.
35
What is the stock size tire for a 1994 sierra Z71
Tire size is 235's. That is the stock size.