Tire size question

[1984 t type]

About to pick up a stock 84 Jimmy, suspension seems to be in real good shape and the springs do not appear to be sagging. Currently it has the stock rally wheels with 31x10.5r15 tires on it, it needs new tires and i am purchasing it out of town while im here on business and planning on ordering new wheels and tires and having them delivered to my hotel and driving it home. What im wanting to do is order a set of 18x8.5 -6mm rally wheels and mount some 285/60/18 Atturo Trail Blade X/T tires on it, they measure out at 31.5x11.5x18 so a half inch higher and 1 inch wider. Has anyone ran this size tire or think i will have any issues with them on a good stock suspension truck ?

Thanks

[rpmerf]

I sold my neighbor my 89 K5 Blazer. He put 33x12.5s on it. They seemed to fit well. Pretty sure I drove it once after they were on, and didn't notice any rubbing. They filled out the wheel wells really nice.

[Ski-me]

It will fit fine, I'm sure....being around 31" tall. Offset might be worth looking at, just in case though. BUT, 18" wheels may look different on these trucks. Personal taste is the main thing, but I will say that I don't see a lot of this era of truck on much bigger than 16" rims.

I've had 32x11.5r15 and 33x12.5r15 on stock height 4x4 blazers. You may have a touch of rubbing on the 33's.

[1984 t type]

Any idea what the ideal offset would be on a 17-18” rim ?

[rpmerf]

Depends how wide it is. Offset is based on width, not diameter.

https://www.tirerack.com/tires/tiret...jsp?techid=101

[trukman1]

I ran 33x12x15 BFG All-Terrains on stock wheels on a 1983 GMC Jimmy and had no issues whatsoever. Great ride and looked better than 31's IMO. Just saying.