How to Get Wider Tires on Trailer With ST145R12 Tires

Question:

I guess I should say wider as in 8 inch of tread area

asked by: JOEL P

Expert Reply:

The 5.7 inch width of a ST145/R12 tire is by far the widest 12 inch tire, so in order to get a wider tire you will need to upgrade to a ST175/80R13 tire, which measures 7 inches wide. This means you will also need new, 13 inch wheels for the tires to fit.

Assuming you have the clearance and you have a 5 on 4-1/2" bolt pattern (if you aren't sure you can use the guide/template I linked below), you simply need to choose the option with the correct load capacity, either C or D:

- Load Range C, 1,360 lbs: Karrier ST175/80R13 Radial Trailer Tire with 13" Galvanized Wheel # AM31952

- Load Range D, 1,610 lbs: Karrier ST175/80R13 Radial Trailer Tire with 13" Galvanized Wheel # AM31994

Then for lug nuts what you will need are the Trailer Wheel Lug Nut - 1/2"-20 - Stainless Steel # KALN1375S.

Finally, please keep in mind that you still need to have at least 3" of clearance from the top of the tire to your fender and at least 1" of clearance between the inside of the tire and your trailer's frame rail.

expert reply by: Kyle S

Joel Z.

12/2/2021

I guess I should say wider as in 8 inch of tread area

Kyle S.

12/2/2021

The 13 inch tire and wheels I mentioned have 7 inches of tread, but if you are looking for something wider then you will need to go up to a 14 inch tire and wheel combo: - Provider ST205/75R14 Radial Trailer Tire w/ 14" White Mod Wheel - 5 on 4-1/2 # TTWA14RWM This ST205/75R14 tire and wheel measures 8.5 inches wide and 26.14 inches in diameter.