Why Cant You Run 16 or 17 Trailer Wheels On Trailer with 3,500 Lb Axle

Question:

Hello, I have a 3500 lbs tandem axle cargo, that Im flipping the axles on to fit bigger wheels and tires. I keep reading that 3500 lb axles can only run up to 15 inch rims. What is the limiting factor? For example: how is a 31 x 10.5 x 15 any different from a 31 x 10.5 x 17? Same diameter, same amount of rotations, same psi, same weight in some cases. That would mean that I could run 33 inch tires on 15 inch rims and be safe, but not 30 inch tires on 18 inch rims? I dont understand. Please explain. Im confused. Thanks! Wayne

asked by: Wayne C

Helpful Expert Reply:

The limiting factor for trailer wheel size is going to be either clearance or the hub. It's pretty obvious why you'd run into clearance issues if you don't have room but the hub is not so obvious. The reason there is a limitation here has to do with surface area on the hub and the contact it makes with the wheel. This is why all trailer hubs have a wheel size rating. There is also a concern with bolt pattern and the lack-there-of larger patterns on these smaller hubs. The Dexter Trailer Idler Hub Assembly part # 84555UC1 or Dexter Trailer Hub and Drum Assembly part # 84546UC3-EZ will allow you to run the largest wheel possible on a 3,500 lb axle which is 15". I have attached our wheel/tire combos below as well.

expert reply by: Conner L