​What makes a Trailer Tire Different from a Normal Car Tire?

You may think that a tire is a tire, right? Well you would be wrong. While most understand that ST (Special Trailer) tires are used for different purposes than for what other tires such as passenger tires are used for, most don’t realize that they need to be cared for differently as well.

When taking care of a normal passenger tire you know that the tread of the tire is a good measuring stick for the life of the tire. Some think that this same thing applies to trailer tires. But they neglect to factor in the irregular usage a trailer and its tires receive. Each type of tire is constructed differently depending on what the tires main purpose is. A LT (Light Truck) tire is built a little differently than a ST tire. Special Trailer tires are fundamentally different at their core, they are designed to be under constant stress and to carry heavier loads than most tires, with this is mind their sidewalls are built stiff to reduce sway in the trailers they are mounted on.

(Maybe Diagram of how ST tire is made here)

This design however can be an issue when it comes to inflation. Usually a tire will begin to sag prompting the owner to check and inflate the tire. With stiffer sidewalls a tire may be underinflated without seeming so at first glance. A trailer owner needs to check the inflation in their trailer tires before every trip. Inflation is very important because the trailer can be overloaded without you even realizing it. Under inflation also produces excess heat which could lead to a blowout.

With most tires, the amount of miles on the tire is usually the biggest factor on whether or not the tire is worn down. But with trailer tires the important thing to keep tabs on is the age of the tire, not the number of miles. Trailer tires have a very abnormal usage cycle, sometimes they will go months without being used. During this time seasons change, the temperature will fluctuate drastically at times, and sunlight is constantly beating down slowly damaging your tires. This along with oxidation that will occur on the rubber of the tire will all affect the tires lifecycle. Trailer tires need to be replaced as recommended which is usually every three to five years, regardless of miles on them.

Another thing that most trailer owners don’t know is that Special Trailer tires have a maximum speed limit usually at about 65 mph under normal conditions. If you exceed the maximum speed then heat can build up in the tire causing it to fail or break down. This will also effect a tires load carrying capacity because the capacity will slowly decrease as the heat and stress by higher speeds increases.