tire size?

[1971C10Blown]

what is the biggest size tire you can fit on a stock suspension truck with stock box. front and back. can you fit a 305on the back and a 275 on the front? also how tall. I'm using an 18" wheel no backspacing yet. also truck has leafs.

[Mike C]

My truck is a stepside, so if yours is a fleet you can probably get away with a bigger tire. Rim diameter doesn't have a whole lot to do with fitment. Section width and overall height do.

I have 275 55 17 on the rear on a 17x9 wheel with 5" backspacing. This is pretty much as big a tire as you can get on a step without inner bedside mods or lip rolling. I have a DJM flip that lowers the truck about 7".

On my truck I went with a narrower tire on the front because that's the look I wanted. 235 55 17 on 17x8 with 4.5" backspacing.

I swapped in a wider '72 rear axle. If your truck is a 71 like your screen name you have the wider rear. If it's a 70 like your signature it's probably the wider but no guarantee. That affects backspacing tremendously.

[OKGMC4]

I am curious about this as well. I have a 4.5/6 drop and would like to run 10" rims all the way around with 305/35r20 tires. I just don't know how far the stock inner fenders can be pushed. Everyone seems to have skinny tires on the front, or the pro touring trucks I've seen run big tires up front with no inner fenders at all.

[1971C10Blown]

Originally Posted by Mike C

My truck is a stepside, so if yours is a fleet you can probably get away with a bigger tire. Rim diameter doesn't have a whole lot to do with fitment. Section width and overall height do.

I have 275 55 17 on the rear on a 17x9 wheel with 5" backspacing. This is pretty much as big a tire as you can get on a step without inner bedside mods or lip rolling. I have a DJM flip that lowers the truck about 7".

On my truck I went with a narrower tire on the front because that's the look I wanted. 235 55 17 on 17x8 with 4.5" backspacing.

I swapped in a wider '72 rear axle. If your truck is a 71 like your screen name you have the wider rear. If it's a 70 like your signature it's probably the wider but no guarantee. That affects backspacing tremendously.

i really like that truck

[Mike C]

Thanks! I've had it for almost 15 years and it's been lowered for 5 days! Been fun driving it around this week.