Things To Consider When Increasing Trailer Wheel Size  

Question:

Helpful Expert Reply:

There's two primary considerations you'll want to take into account before swapping your existing 8 inch rims for 12 inch rims.

The first is the wheel bolt pattern. A 4.80-4.00-8 Tire would typically be mounted on an 8 x 3-3/4 inch wheel and would have either a 4 on 4 inch or a 5 on 4-1/2 inch bolt pattern. The 12 inch rim you choose would need to have a matching bolt pattern. The wheel's pilot diameter is really only important if it's a hub-centric wheel that uses lug bolts to attach the wheel to the hub, rather than wheel studs and lug nuts. If your existing wheels are hub-centric, you'll want the rims you choose to have the same pilot diameter as your existing wheels.

The second consideration is the clearance between the top of the tire and the underside of the fender or wheel well when the trailer is under load. With the trailer under load, you'll want to have at least 3-4 inches of clearance there to allow the suspension to articulate.

Since a 4.80/4.00-8 tire typically has a diameter of around 16 inches, and a 4.80-12 tire that would be compatible with the # AM20132 rim you'd looked at would have a diameter of 20.7 inches, you could have clearance issues unless you moved or replaced the fenders, as the taller rims would move the tire tread about 2-1/4 inches closer to the underside of the fender or wheel well.

I've linked to our series of help articles on trailer wheels and tires, which contain tons of information that you might find helpful.

expert reply by: Mike L

1