I have tried and tried searching and can't find anything, so I'll risk posting what HAS to have been asked a million times...

On the 88-91 Trooper, what's the largest tire that can be mounted without rubbing? I am interested in what will specifically fit a Trooper with a stock ride height. Are 31's as big as they go (largest OE tire)?

I was at a 1.5" lift or so (t-bar crank and shackles) but I had all kinds of alignment and ball joint problems since I was using aluminum shims and no ball joint spacers. I'd consder going back and doing that "right" if it's what it takes to fit a larger tire than the 31.

I'm also specifically looking to use a 7" 0 offset wheel like the "Wide Tire" option (with 31's) from the factory used. The wider offset will help clear stuff on the inside, but might violate the fenders. As it is, my 31x10.5's on these wheels look like they are close during compression of the suspension.

Thanks!!!

I am affraid this topic has been hammered unmercifully...

search for "tall and skinny". I made that comment in a post and folks replied about tire sizes. HTH - JL

EDIT - I have 31x10.50 on 15x8's with 3 5/16 BS without rubbing. Suspension/truck height is still stock.

FWIW - I've got a 91 Trooper running 33x10.50 BFG AT's on plain old Discount Tire black steelies. No rubbing. Just no power...

- mike

Thanks, jackleg, for the search tip. Will do. What's a "BS"?

sweater, are you on stock ride height? Are those rims zero offset? IIRC, the OEM steel wheels w/o the "wide tire" option had an 1/2 or 1" of offset (wheels inset 1/2" or 1" more than the wide tire ones).

Edit: So I know now that 33x10.5 will fit fine, no rubbing... will 33x12's fit?

Other than the commonly-known variety (bull----) the other use of that term on automotive forums refers to "backspacing" -- in his case, 3 & 5/16ths. Backspacing and offset usually go hand-in-hand, although there are some variances. In any case, 3 & 5/16ths BS on an 8-inch rim would equate to an offset of -11/16ths, or in the more commonly-used metric, -17.5mm offset, or somewhere right around there. That's a pretty high negative offset, which would only serve to hit the fenders more than a neutral offset... So if you're planning on 0-offset rims, I'd bet you'd get away with the same tires without any issues at all... As for the 12.5's, well... Lemmie think about that a minute. Sweater's tires are set outboard an additional 17.5mm from where yours would be... In other words, his rims will emulate a tire that is 35mm wider than his tires really are, at least on the outboard side anyway. Frame rub is a different story, but as far as the fenders are concerned, his tires appear to be 35mm wider (approx 1.5 inches) than they really are. So the question is, Sweater, ya think you'd be able to fit another 1/4-inch of tire width on there without rubbing? Check it at steering lock where the tire comes closest to the fender, and speculate whether or not another 1/4-inch would be a deal-breaker or not...

-Chris

-Chris

Thanks, Chris.

By my math, if a 10.5 will work with a ~ .7" negative offset, then putting on a 12 with .75" more tire on the outside of that MIGHT work. That's assuming that I don't run into trouble with the "more" tire on the inside.

That said, my new question: has anyone has run a 33x12 on the "Wide Tire" (7" wide, 0 offset/3.5" BS) rim on the 88-91 with no lift...

Chris is absolutely correct. about 1.5" more toward the outside on the truck. Note the pic. Tires sticking out



This is why I listed the "bs". Wheel size and the BS is what (to some degree) limits or dictates tire size allowable. I liked these wheels even though they do not have the most desirable "bs". In my case (these wheels), I would have to lift the truck to get a tire any larger in width or diameter and they would stick out too far for my liking. 10.5 is as far as I think I am going. However, one could get fender flares and chop fenders. This is a better option in my opinion than rubbing steering components or frame rails.

I do not think 12.5 would fit. You "should" use a wider wheel for that tire size. Even if you could find a wider wheel with the correct "os/bs", I think they would rub.

Now, Mike's tires are most likely on the stock plane (same centerline as the original tire) where mine are about 1.5 outboard. - JL

33x10.50's fit fine on 15x8 rims. Have them on my RS.

I have 33x12.5's on 8" rims with I believe 4.75 (4.25 at the very least) backspacing I think (they were customed ordered by Eric, the previous owner). They stick out pretty far, and w/o lift rub on the fenders and with an inch or so on lift rub on compression in turns. I stuffed the rear the other day and got it to touch as well.

Well worth the rub for the look to me, but not really feasible to take off road.

From what I remember about this, 33x10.5's were fine, and it's the width that's the deal breaker.

JL, those are 31's, right? That's what I'm running now, on 3.5" BS 7" wide rims, no rub.

Thanks for all the input, people. Sounds like the 12.5's might not fly w/o rubbing w/o lift, especially in 33" trim.