Clearance Required to Change to Larger Trailer Tire Size

Updated 01/02/2019 | Published 12/30/2018

Products Featured in This Question

Kenda 215/60-8 Bias Trailer Tire with 8" White Wheel - 4 on 4 - Load Range C

(7668)

$84.47

Kenda 215/60-8 Bias Trailer Tire with 8" Galvanized Wheel - 4 on 4 - Load Range C

(7532)

$100.00

Kenda 205/65-10 Bias Trailer Tire with 10" White Wheel - 4 on 4 - Load Range E

(7668)

$106.23

Question:

I have a 24‘ x 8.5’ snowmobile trailer. It currently has 18.5 x 8.5 x 8 tires on it. I measured the distance from the ground to the trailer where the tire resides and have 24 inches total. I’d like to increase the size and weight rating for the tires on this trailer. What is the largest highest load rated tire I can replace the old tires with? They are 4 lug hubs.

asked by: David G

Expert Reply:

The metric equivalent of trailer tire size 18.5 x 8.5 - 8 is size ST215/60-8 and these have the same overall diameter of just over 18-1/4-inches.

In this tire size we offer two items with the 4-on-4 bolt pattern, and both are Kenda Load Range C items, part # AM3H290 for white and # AM3H300 for galvanized. Both have a weight capacity of 940-lbs at 50psi.

You want to maintain at least 3-inches of vertical clearance above the top of the tire tread to allow for the normal travel of your trailer's suspension. At the tire sidewall you want to maintain at least 1/2-inch between the sidewall and the trailer frame.

If you have enough clearance you might use tires in size ST205/65-10, which are 20-1/2-inches in diameter. For a 4-bolt wheel with a high load range E rating tire you might consider # AM3H460 which is rated for 1650-lbs.

Using tires that can handle more weight than they actually have to support tends to mean they will run cooler, and cooler-running tires do typically last longer and have fewer heat-related failures.