What Causes Cupping Wear On ST205/75-15 Trailer Tires And Should I Use Radial Or Bias Tires

Published 01/13/2011

Products Featured in This Question

Loadstar ST205/75D15 Bias Trailer Tire - Load Range C

(3888)

$85.00

Karrier KR03 ST205/75R15 Radial Trailer Tire - Load Range C

(2348)

$121.56

Question:

I need tires for my 3500# single axle utility trailer. It currently has Carlisle ST205/75 15 on it. Loaded I carry just under 2,000 lbs on the trailer. The last trip I make, I noticed that the Carlisle tires had started a severe cupping wear on the threads. I like to step up to a load range C, but not sure whether to go bias or radial.

asked by: Hank M

Expert Reply:

When you have cupping wear on a tire it is from the tire bouncing on the road. You will want to check the air pressure in the tire and make sure you are running the maximum air pressure that is indicated on the tire.

Then, I would recommend to have the tires and wheels balanced. Another thing to check is the suspension parts on the trailer. When suspension parts begin to wear and get loose it can cause the tire to hop when being towed and cause the cupping pattern.

The load range (B, C) of the tire or the tire construction (bias, radial) will not make a difference in the problem with the cupping wear.

The ST205/75-15 tire size in a load range B is rated at 1,480 lbs. at 35 psi. So total capacity of two tires on your single axle is 2,960 lbs. The load range C is rated at 1,820 lbs. at 50 psi. So total capacity of two tires will be 3,640 lbs. I would recommend to use the Karrier ST205/75R15 Radial Trailer Tire - Load Range C, part # AM10244, for your 3,500 lb. trailer.

I would recommend the radial tire over the bias tire because of better stability, better ride comfort and it will also dissipate heat better. Heat buildup inside a tire is what will cause many problems with tires. Radial trailer tires will also give you longer wear.

I am including a FAQ page on tire information.

expert reply by: Jeff D