What is the maximum tire size that I can use on my stock spare tire rack (whitout any modifications).
Is there any problem with the 265/70/17 size?
Many Thanks

 

That size is just slightly larger than stock. I don't know for sure, but I can't imagine it would cause you any problems. I've seen much larger than that hanging off the stock carrier.

 

I managed to fit a 35x12.50x17 m/t tire back there. No issues

 

Wheel backspacing will have something to do with it. I'm not sure about stock wheels but I run AEVs with BFG KM2s in 315/75 r/16 (35") and it's a perfect fit: the tire rests a little on the scalloped-out portion of the stock rear bumper, hopefully taking some of the extra weight load off the tailgate.

I still want an aftermarket rear bumper with tire carrier but don't have that kind of cash laying around at the moment

 

Running 285/75 (read ~ 33 x 11.5) load d's back there, and though I can tell it's heavier, I don't see any issues.

 

Mine had Cooper tires in that size when I bought it. They fit fine, just make the small bumpers on the tailgate are the right length. May have to trim them a bit if you're stock wheels, or get the longer daystars if you have different wheels.