Discussion in 'Wheels and Tires' started by Howard Rogers, Feb 16, 2020.
what is the biggest tire i can run on stock suspension.. 1986 gmc 2500 4x4... thanks
I ran 31x10.5x15s on my 87 Suburban 4x4 (1/2 ton) when it had stock suspension, no clearance issues whatsoever.
Ive got the same size on my 2wd 78 with saggy front coils and no issues.
I am pretty sure you can fit 32's
I'd say 31's. I had 33x12.5 on my k20 but needed a 2" lift.
The tires would hit the back fender opening unless you want to clearance.
My k5 came with 31x10.5 from the factory.
If you're using the factory rims then 33x10.5x15. That's what I run. 12" wide you'll need a lift.
I had a 4x4 3/4 ton Suburban that ran 33"x12.5's and factory wide steelies on bone stock suspension. No rubbing even offroad.
But there's a definite gray area with 33's. A 1/2 ton will almost certainly need trimmed. The exact same wheel and tire combo can actually rub on the same truck with lift springs. Soft lift springs can provide much more axle droop, so if one side is dropped and the other side is stuffed, it can put the stuffed tire closer to the fender than with stock springs.
I have run 31x10.50x 15 on my 87 stock short box 4x4 for decades. Even when airing it out they do not rub.
First picture is Frankenchevy's truck. He is running 285/75R16's (32"x11") with 16x8's with 4"BS on his K30 w/o rubbing. They would probably fit a K20 without issues. Second picture is my truck (also K30) before I bought it with old school 33x12.50x16.5's on a 9.75" wheel. It has minor trimming on the front fenders.
31x10.50x16 no rub.
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