jeep98b

Would i need to do anything to run 33's with 4.5 lift or should I stick with the 31's? There are two local guys sellind 33" BFG M/T's for $300 with steelies that have decent tread. Thanks

jeep98b

No extreme offroading in the near future.

COSXJFAN

It will fit, but you may have to do some trimming to keep them from rubbing.

Kyle

Some trimming and bumpstopping may be in order but other then that you should be good to go.

TrueBlueXJ

Yep, just trim your fenders and add some bumpstops and you should be fine. That's a pretty ideal setup IMO. Low center of gravity is always good.

JakeWI

yeah. i ran 31's under my 4.5 RC. it was good, no trimming and turned easily. but like they all said 33's would be a great set up. with 31's under 4.5" you can easily tell there is a lot of room to step it up to 33's

jeep98b

Great info as always. Any gearing issues? Got 3.53's

Kyle

You have 3.55s

And if you are doing a lot of freeway driving I would recommend 32's over 33's because you are going to lose a lot of power. But many say 33's are the largest tire size that they would run without a re gear.

COSXJFAN

Yes, you will have considerably less power with 33s. At least 4.10s, if not more is what you need to regain your lost power. I have 33s and 4.88s on mine and love it. I do a lot of rock crawling and need as much gear as I can get!! Later!

dabeast727

With those gears if you dont want to regear, id go with 31s. They will be fine for now just do not trim your fenders. If you do, they will look tiny, otherwise they will look fine and your gas mileage will be decent. hoiw big your tires look is always relative to your lift

Also, what axles do you have?

jeep98b

Yeah I meant 3.55's and I have the 8.25 out back and 30 front. I do alot of highway driving. I have actually thought about leaving it at 3" and get bumpers and just keep the 4.5 stuff til' I can afford to do everything that i want for the 4.5. Or go with 32x 11.50's. Don't know.

Kyle

If in the future you plan on a regear I would say you are fine with 33's. But I dont think you will like the way it performs after long periods of time.

BlueXJ

This is the formula for gearing decisions.
Deciding what gear ratio to use when changing tire size is actually quite simple.
It's just a matter of mathematics.

Current tire size/new tire size =current gear ratio/new gear ratio

This simple formula will allow you to figure out what ratio will get you back to your current performance.
For instance, let's say you have stock 3.55 gears & stock tires and want to go to 33" tires.
Stock XJ tires are about 27" tall so:

27/33 = 3.55/new gear ratio

Cross multiplying (thought you'd never use algebra again?) gets you this:
33 X 3.55 = 27 X new gear ratio

117.15 = 27 X new gear ratio

117.15/27 = 4.34

IOW, 4.56 gears (the closest avail to 4.34) will give you slightly lower gearing than you had while stock.
From here it's up to you where to go.
If stock performance is fine stay with 4.56. If you want a little more low end grunt, go to 4.88. If you want to murder the rocks go to 5.13 or lower.
BTW, lower gears = higher numerically

okcjeeper

good call on the formula there bluexj...

BlueXJ

Simple math. Hope that it helps those who are wondering what gear set to choose.