Fit 31 inch tires on Jeep Wrangler YJ with 2.5L engine

We will approach this modification from 3 angles:

• the space available in the wheel arches and the play with the suspension and steering elements
• engine and transmission performance and reliability
• and most importantly security

Physical aspect

The best tires for jeep wrangler of 31 x 10.5 x 15, or about 245/75 R15 or 255/75 R15 — note that if the rim is 16 in diameter the problem is exactly the same — these are the external dimensions of the tire here it’s about.
So this 31 tire can be mounted on an original Jeep Wrangler rim (15 x 7); this is not where the problem lies.

If you decide to mount 31 x 10.5 on your original Wrangler, the first thing you will notice is that the space available , especially at the front, between the top of the tire and the underside of the passage of wheel, will be reduced to 4–5 cm when the Jeep is flat on its wheels, at the rear you will have more, from 8 to 10 cm. The aesthetic problem also arises: the tires seem too big for the car.

The second problem is dynamic : when you climb on a sidewalk, the tire will touch the wing , which will be much worse when you cross the bridge; there the tire will machine the plastic expander and then the sheet metal.
Finally, the third problem of the size of these tires is in turning, in abutment; rear tire will rub against the blades , specifically the blade reinforcing flanges before that the pivots not abut on the hands of the bridge .

The reliability and mechanical aspect

If you want to give you a mechanical idea of ​​your Wrangler once the 31 tires are fitted, you can do a simple test which consists of starting in seconds, shifting all gears before 1500 laps, and driving in 5th gear at 70km / h. When modified with 31 tires, your Wrangler will look like this! It goes without saying that it is very soft, very unpleasant to drive, and also that it tires the clutch . As for the rest of the transmission , the box and axles are strong enough to support this size of tire.

A final non-negligible point is the increase in consumption: count between 14 and 18 L per 100 km with a2.5L Wrangler and 31 tires.

Finally the last point: security

As said above, the tires rub either on the fenders or on the blades when you steer. It goes without saying that it is dangerous because it can cut the tire, and eventually burst it. It should also be noted that a Jeep equipped with 31-inch tires will be refused in most technical inspections, because it does not correspond to the original tire .