Self-Clearance Prevention

Whether you are new to wheeling, or you've just gotten a new-to-you Jeep, we've all wondered at some point about the biggest tires that would fit under our Jeep. Despite knowing a whole lot about this addiction we call Jeeping, we've recently added to our Jeep stables. Now we're right back at the beginning, so to speak.

There are a lot of factors that figure into this. Wheel backspacing and rim width for particular tires are important to consider. Read the manufacturer's specs of the tire you are contemplating because they specify it for a set rim size. Skinnier rims mean more sidewall bulge, which might cause interference. Wider rims will equate to less sidewall bulge, but might mean the tire will hit on the fender, or you won't be able to air down as far. More backspacing means you might hit suspension components, and less often means that you'll interfere with your fenders.

We all use our Jeeps lovingly (read: abuse them). Due to frame tweakage or spring sag (or just maybe the bevy of women you are toting in the back of your Jeep), all the circumstances will be different, and will play a big part in what hits. This is a basic guideline for what you can run on your Jeep, but if you aren't sure try to find people with a similar Jeep and ask them about tire sizes.

No one has put together a table of sizes for all Jeeps like we have here. Sure, we skipped the M-726, M-170, M-678, CJ-4, and CJ-10A. But just how often do you see one of them? Some models we don't feel are safe or stable with the stock-width axles and wheelbase above a certain lift or tire size, and some we don't feel have the power to turn the bigger tires. If you are swapping any of the major drivetrain components, use this as a reference and go from there. Keep in mind the tire sizes are actual sizes, so use the P-Metric sidebar in this article for a reference to your tire size if you've got a metric tire. If you've got a standard-size tire, subtract an inch from the advertised size on the sidewall. As usual, the best bet is to actually measure the tire in question.

Flatfender
A stock flattie on stock rims can clear 30x9.5, but add a set of 15x8s to the mix with 3 - 3 1/2 inches of backspacing and you can clear 31x10.5s with rare instances of rubbing. The wider tires will tend to rub on the springs unless you run with very little backspacing. Overall, with an otherwise stock flattie (engine, transmission, and transfer case) we'd put 31s on it and run it like that for the nostalgia factor.

Early CJ-5s and CJ-6s
These can clear 30x9.5 tire with no problems, stock rims or not. A 31x10.5 can clear with the stock rims, but up front they'll hit the springs at full turn and the top of the tire will tag the inner fender when articulating. You can also put a set of rims on with less backspacing and you can clear the springs up front, but they might contact the fenders in the rear. Again, with a stock drivetrain, we'd put 31s on it and trim wherever needed.

Long-Nosed CJs
The later CJs with their larger engines and slightly larger wheel openings, as well as wider axles changed things a bit. 31s are possible on stock rims and it just goes up from there. While you can run 40s on all of them, we'd only feel OK with them on a Wide-Trac CJ-8 (and only then if we liked replacing axle shafts). Anything else would be very scary.

YJ Wrangler
Smaller stock tires come standard because of YJ's lower stance. With a set of 30x9.5s on the stock rims, you will self-clearance the fender flares. Ditch them and add TJ flares for the ability to put 31s on it if your springs aren't sagging a whole lot. For anything wider than a 10 1/2-inch tire, you'll want aftermarket rims with 3 1/2 inches of backspacing. Stock rims with wide tires will have you hitting your springs at every turn. We'd put 33s on it with a 4-inch lift and TJ flares, then call it done.

TJ Wrangler and LJ Wrangler Unlimited
With 31-inch tires out of the factory, they obviously fit. Add a 1-inch body lift, and 32s will just squeeze under there on the stock rims. But keep them to 9 1/2- or 10 1/2-inches wide. Like the YJ, with anything wider than 10 1/2 inches on the stock rims, there will be contact with the suspension components. With a TJ, we'd put 33x12.5s on 15x8-inch rims with 3 1/2 inches of backspacing. On the LJ, we'd go to 35s and keep the rest of the recipe the same.

P-Metric Mania
The 235/75R15 isn't that hard to translate into a normal usable number. The width is 235, the aspect ratio is 75, and R15 is the diameter of the rim. To use that when shopping for tires, use these two formulas:

Actual Height (in inches) = ((Width x Aspect Ratio x 2)/2550) + Rim Diameter

Actual Width (in inches) = (width / 25.50)

If you aren't a math guru, here are some common P-Metric Tire sizes converted for you.

Click here to see tire guides for ALL other Jeep models.