Factors to Consider When Increasing Wheels on a Trailer from 8 Inches to 13 Inches

Updated 04/11/2012 | Published 04/10/2012

Question:

What considerations should I be making to increase my wheel size from 8 inch to a 13 inch wheel for my harbor freight 5x8 trailer? It currently has a 8 inch 4 on 4 bolt pattern wheelset.

asked by: Chris

Expert Reply:

The factors that you will want to consider when increasing your tire size are wheel bolt pattern, tire width, tire clearance and overall trailer height.

You will want to keep the same bolt pattern as your current tires. The Kenda Loadstar ST175/80D13 Tire, # AM3S130, that you referenced has the same 4 on 4 bolt pattern as your current tires so that will work.

The next thing to check is your tire width, or section width. Increasing the wheel size may increase the section width of the tire since the wheel width will most likely change. If the new tire and wheel are wider, then there may be a chance the tire could rub on the trailer frame.

The section width of the Kenda Loadstar tire that you referenced is 6.6 inches. It is likely that you are currently using a tire similar to our Kenda 4.80/4.00-8, # AM30000. The section width of this tire is 4.6 inches. Assuming that your current wheels have a zero offset the new tires will be 1 inch closer to the trailer frame. I am not sure of the exact tire you have so it is important that you know your actual tire size.

The third thing to check is the tire clearance in your wheel well. For this you will want to know the outer diameter of your tire. The outer diameter of the 4.80/4.00-8 tire is 16.1 inches and the outer diameter of the Kenda Loadstar tire you referenced is 24 inches. This should give you a better idea of how much room the larger wheel and tire will require.

The final factor is the overall trailer height. Increasing the the ground clearance of the trailer will raise the center of gravity resulting in added sway when driving. This is usually a concern with larger trailers, but you could experience issues when using tires that are larger than the tires that came with the trailer.

I have attached a few articles for you to review when selecting tires for your trailer. They also explain how to take the different measurements of your tires.