what brand tire we talking here ?? If they are Nitto Trail Grapplers the 35/12.50's are 13.39 wide and 35.04 tall with an agressive sidewall lug..

backspaceing

If it was the 295/65R20 it would be trail grapplers if it was the 35x12.50R20 it would be cooper STT's
The back spacing on my rims are 6.13

You'll be fine with either tire.

Ok I'm gonna go with the 35x12.50R20 cooper STT's then

You can have Brad come over and do any trimming you need done...

^ Is a dick!!!

I've ran mulitple wheel tire setups so I'm just trying to help the guy out. I actually had 2.5 autospring and 3" block and 295/65/20's for a couple weeks on stock wheels and didn't rub at all. My buddy has pretty much the same setup has the op 20x9 +35 KMC monster with toyo m/t 35x12.50x20.

I agree with brad. There are tons of guys on here running a 35x12.50 on stock wheels with no rubbing. The only rubbing you may experience will be on the upper control arms, this may or may not occur, but has been known to do so. If it does a small 1/4" wheel spacer will stop it. Cooper tires in my experience with them tend to run a little small anyways.

I run 34s on the stock rim and they rub a little on my mud flaps with a 2 inch level.

Thanks for the kind words Brad... all I wanted to do was like the OP know that all 35/12.50/20 do not measure the same...some are as wide as 13.5" and will cause rubbing if not installed on the proper wheels...the Cooper STT's measure 12.5 wide and 34.66 tall on a 10" wide wheel...so your right he should be fine. so...what tire you running now ? 295/65 or 295/60 ?