This thread is a subjective mess. Everybody has a different setup on their blazer. By this I mean no blazer sits exactly like any other so somebodies advice may not apply to certain blazers. Factors like z85 package, how old your blazer is, sagging leaf springs, torsion bar movement etc...

The general rule of thumb however is some lift is needed to make 31s or bigger work. If you have lower backspacing than stock (4wd only) and add a body lift you will probably need to trim the fender a bit still. If you have stock backspacing and the wheel still sits all the way in the fender, chances are 31s will rub the frame. This is fairly unsafe, if you have to swerve at any speed you risk a rollover (tire hits frame at a certain angle). To counteract this, a suspension lift of some kind is necessary. (Imo, body lifts work better if you have a lower backspacing.) If GM knew 31s would fit ALL blazers at the stock height they would have put 31s on these trucks from the factory. It is common sense now to think some modification will need to be done to fit something that originally didn't come on these trucks. (This statement doesn't hold true for Zr2's obviously, because they have 31s stock.)

 

FWIW my old truck had 31" BFG's with stock wheels and the t bars cranked / shackles. It barely rubbed the frame at full lock when making a u turn... other then that it didnt rub at all, even offroad with the sway bar disco'd.

When i switched to steelies with 4.5" backspace i had to chop the fenders quite a bit... and it still rubbed.

 

[QUOTE=KM346;574257]FWIW my old truck had 31" BFG's with stock wheels and the t bars cranked / shackles. It barely rubbed the frame at full lock when making a u turn... other then that it didnt rub at all, even offroad with the sway bar disco'd.

When i switched to steelies with 4.5" backspace i had to chop the fenders quite a bit... and it still rubbed.[/QU

yea imma just stick with 30x9.50 in bfgs cuz if you had to trim with 4.5 back space i only got 4 although i am gettin.2.5"lift but they still wouldnt clear im not butchering the truck.up with a saws all to clear tires hell my grandmother helped me get the truck ive got other things i could do after i do what.i have ordered

 

Heck I'm far from stock offset and I rub something horrible on near stock size tires