How To Read Trailer Tire Tread Wear

Tire Wear

The way your tires wear is a good indicator of the condition of other parts of your trailer.
Abnormal wear patterns are often caused by the need for simple tire maintenance. Trailer tires should be inspected at every opportunity; once a week isn't too often if you are pulling a trailer that often.
Learning to read the early warning signs of trouble can prevent wear that shortens tire life or indicates the need for having other parts of the trailer serviced.

Trailer Tire Wear Patterns

trailer tire under inflation wear pattern

Under Inflation

This type of wear results from consistent trailer tire pressure under inflation.
When a trailer tire is under inflated, there is too much contact with the road by the outer treads, which wear prematurely.
Trailer tire pressure should be checked often, with a reliable pressure gauge.

trailer tire over inflation wear pattern

Over Inflation

Excessive wear at the center of the tread indicates that the air pressure in the trailer tire is consistently too high.
The trailer tire is riding on the center of the tread and wearing it prematurely.
Trailer tire pressure should be checked often, with a reliable pressure gauge.

trailer tire one side wear pattern

One Side Wear

When an inner rib wears faster than the rest of the trailer tire, this usually indicates a bent axle.
When an outter rib wears faster than than the rest of the trailer tire, this usually indicates excessive camber in the axle.

trailer tire cupping wear pattern


Cups or scalloped dips appearing around the edge of the tread on one side or the other, almost always indicate worn (sometimes bent) suspension parts.
Any worn component that connects the wheel to the trailer (wheel bearings, springs, bushings, etc.) can cause this condition.
Worn components should be replaced with new ones.

trailer tire feathering wear pattern


Feathering is a condition when the edge of each tread rib develops a slightly rounded edge on one side and a sharp edge on the other.
By running your hand over the trailer tire, you can usually feel the sharper edges before you'll be able to see them.
The most common cause of feathering is a misaligned axle.

What's The Difference Between Trailer Tires And Passenger Car Tires

Trailer Tires Vs Passenger Car Tires:

There are distinct differences in the way passenger car tires (P) and special trailer tires (ST) are designed, engineered, and constructed. There are also differences in the service requirements between the tires on your car or truck and those on your trailer.
Traction, or grip, is a key element in the design of passenger car tires. Traction moves your car or truck down the road. Traction allows you to stop, turn and swerve, and traction also gives you the ability to tow your trailer. Another important consideration in passenger tire design is "ride". Ride, traction, and handling are all achieved in passenger tire designs by adding flex in the sidewall. By making the sidewall more flexible, tire engineers maximize tread contact with the road, thus increasing traction and allowing the driver to maintain better control over the vehicle. Traction is only a factor on trailers equipped with brakes, during braking operations, because trailers are followers. In fact, sidewall flexing in a trailer application is a negative. Sidewall flexing on trailers carrying heavy loads; trailers with high vertical side loads (boat trailers or enclosed/travel trailers); or trailers with light tongue weights, is a primary cause of trailer sway.
Automotive radial tires with their flexible sidewalls notably accentuate trailer sway problems. The stiffer sidewalls and higher operating pressures common with Special Trailer (ST) tires helps control and reduce the occurrence of trailer sway. Bottom line, trailers are more stable and pull better on tires designed specifically for trailer use. Also consider that all Light Truck (LT) and Special Trailer (ST) tires are fully rated for trailer applications. This means the tires can carry their full sidewall weight rating when used on a trailer. When passenger tires are used on a trailer, the load capacity of tire must be de-rated by 10%. If the tire has a maximum load rating of 1900 lb., it may only be used in a trailer application up to 1710 lb. This means the GAWR rating on the trailer Certification Label must not exceed 3420 lbs. On a single axle trailer, or 2 times 1710 lbs. For trailer use, it is important to match the tires to the application and payload. Since Special Trailer (ST) tires are constructed with more and heavier materials, they are tougher and more bruise resistant than typical passenger tires. This is a plus because trailer suspension systems are generally stiffer and less sophisticated than automotive suspension systems. A tire designed to operate in the more demanding trailer environment will provide end users a longer service life and withstand the added abuse tires on a trailer experience. Bias ply Special Trailer tire technology has been moving trailers around America for nearly 30 years, and more recently, the ST Radial arrived on the scene providing the same durability and dependability in a radial trailer tire.
For many trailer buyers, tire decisions are purely price based. The allure of an equal price and the word "radial" for that price draws some customers to the passenger tire. American Discount Marine hopes this explanation of the differences will help you make a more informed decision on your next trailer tire purchase.