fitting 31s

[xComancheKidx]

just picked up a decent set of 31s and i was just wondering what i need to fit them on my rig without any rubbing

[MrSimon]

Street driving or off-road?

 

2 or 4 wheel drive?

 

Sagging suspension?

 

Willing to trim fenders?

 

As a general rule, without trimming, a two inch budget boost will clear 31s for street driving, 3.5" for off-road.

 

If you want more info on how to do those types of lift, search the site - tons and tons of info.

[xComancheKidx]

off road..4 wheel drive..sagging suspension :fs1:

[Pete M]

Which tires are they? Some manufacturers are true 31s, others are more like 30".

 

Add an inch or so of bumpstop and some WJ lower control arms and you can run them on 0 lift. It'll be tight, but with the proper bumpstopping it should work ok. A full blown 3" kit would be much better though. :thumbsup:

 

 

This is my 90 on 31s (no lift and WJ arms):

[Sir Sam]

This is my 90 on 31s (no lift and WJ arms):

 

Man, non lifted jeeps with good sized tires look awesome.

[Darren]

Put the 31's on. Relocate the flares up a few inches and get some wheels with better backspacing. I've seen guys run 33's on no lift. You just have to trim and bumpstop until it works.

[NWPhotog]

This is my 90 on 31s (no lift and WJ arms):

 

Man, non lifted jeeps with good sized tires look awesome.

 

I second that!!!

[mnkyboy]

here's mine when it was bone stock on 31s,I drove it like this for awhile even went offroad a little. It rubbed bad with the stock wheels but after i changed wheels it was fine. I have the 4cyl so i have less weight out front,thats probably why i got away with it on a stock setup.

[xComancheKidx]

yea i have american racing wheels.not sure on the backspacing...i might be able to pick up a pair of zj coils.. my stock coils are shot and i was wondering if the zj coils would give me any lift?

[Eagle]

ZJ V8 coils will give you approximately 1" of lift. The XJ "Up Country" front coils are the same part number as ZJ V8 coils.

 

But coils will not help you with rubbing. Where tires larger than 31s rub on the front of an XJ or MJ is the lower control arms. Replace those with the LCAs from a WJ Grand Cherokee, and the problem goes away. The WJ LCAs have a bend t clear the tires.

 

And run OEM Jeep rims. They allow the 31s to stuff up inside the flares. Aftermarket wheels all have less backspacing (stick out farther), resulting in the tires hitting the flares and the sheet metal. On OEM rims, 31x10.50s will cycle through the full range of suspension movement without hitting. The LCA rub is on sharp turns, not "articulation."

[dakineJ]

ZJ V8 coils will give you approximately 1" of lift. The XJ "Up Country" front coils are the same part number as ZJ V8 coils.

 

But coils will not help you with rubbing. Where tires larger than 31s rub on the front of an XJ or MJ is the lower control arms. Replace those with the LCAs from a WJ Grand Cherokee, and the problem goes away. The WJ LCAs have a bend t clear the tires.

 

And run OEM Jeep rims. They allow the 31s to stuff up inside the flares. Aftermarket wheels all have less backspacing (stick out farther), resulting in the tires hitting the flares and the sheet metal. On OEM rims, 31x10.50s will cycle through the full range of suspension movement without hitting. The LCA rub is on sharp turns, not "articulation."

What's the least amount of backspacing you can get away with before you have to lift/trim?

[1990 Pioneer 4x4]

...Add an inch or so of bumpstop...

 

Sounds like an easy fix for my BFG 30”MT’s that rub when compressed. :thumbsup: Do you ever miss that 1”+/- in articulation?

[Pete M]

Don't know, I never did it. Truck does a lot of sitting still these days. :(