Increasing Trailer Tire Size for Better Load Capacity & Higher Speed Rating

Expert Reply:

You may simply need to choose new tires in the same size but ones that have a higher weight capacity and/or a higher speed rating. For instance, the Taskmaster 4.80R12 Radial Trailer Tire with White Mod Wheel # TA38RR has a Load Range C weight rating and a speed rating of M, meaning it is rated for up to 81-mph.

Switching to a larger size of trailer tire is sometimes possible. You need to have enough vertical clearance within the fenders/wheel wells and enough lateral clearance between the inner sidewall and the trailer frame. Normal vertical suspension travel for a leaf spring trailer suspension is 3 to 4 inches and I suggest maintaining at least 3/4-inch space between the inner sidewall and the frame. You may need to also swap out your hubs to allow use of larger rims.

Be sure to always run your trailer tires at their maximum rated psi pressure (also noted on the sidewall) and to observe their weight and speed ratings too. Incorrect inflation, overloading beyond capacity and driving faster than the tire is rated to go ALL cause excess heat, and heat is the root cause of most tire failure.

I linked two helpful articles concerning special trailer tires. These will address any remaining questions and will also help with determining the overall diameter of the most popular sizes of trailer tire. Please feel free to tell me more about your current tires.