Upgrading to Larger Tire on Trailer With 4.80-12 Tires

Question:

I have a boat trailer with 4.80-12 tires/wheels on it. I have 3.5” of clearance between the top of the tire and the under side of the fender. If I up size, provide I have enough lateral clearance to the frame, what is the largest tire/wheel assembly I can up size to? It does appear that I have about 3” lateral clearance to the frame.

asked by: Jeff S

Expert Reply:

Your typical 4.80-12 tire like # AM10062 has an outer diameter of 20.5" and section width of 4.8". Since you currently have 3.5" of clearance on top, and 3" is the minimum, you can only move up 1" in tire diameter. This means the only real option would be a tire like the Kenda Karrier S-Trail ST145/R12 Radial Trailer Tire # AM10130.

This tire has a 5.7" section width and 21.3" outer diameter. Neither of these would cause you clearance issues. It will also fit your existing wheels. This has a max load of 1,220 lbs at 65 psi and speed rating of M for 81 mph. Any larger and you wouldn't have enough clearance. Even if you removed the fender, the inside clearance wouldn't allow for the larger sizes.

expert reply by: Robin H