Tow Far - Trailer Tires

Years ago, nearly all ST tires were bias-ply tires, which have crisscrossing cords of polyester or nylon, with the same number of ply on the sides as there are on the tread. Occasionally bias-belted tires were used. These are the same as bias ply, but with added belts, or layers, under the tread.

Bias or Radial?
Since then, however, radial tires have swept the tire industry. Radials feature plies that run perpendicularly across the tire, with belts (some of which can be steel) running under the tread. Today, many ST tires are radials. Is bias better than radial, or visa versa? Actually, each has its pros and cons. In making a decision, it is good to talk to the tire manufacturer about your particular application.


Generally speaking, a bias tire has the advantage when it comes to load and high-speed performance. A radial, however, is better when it comes to tread wear. On average a bias tire's tread will last approximately 12,000 miles, whereas a radial typically lasts 40,000 miles. There are exceptions, of course, but this is an average comparison.

Under-Inflation
Regardless of whether you choose radial or bias, it is crucial that you provide regular tire maintenance. The most common cause of tire problems is under-inflation. It is estimated that a trailer tire that is 20 percent under-inflated will cut 25 percent off its lifespan; one 30 percent under-inflated will reduce its term by 55 percent. Under-inflated tires also affect fuel efficiency by as much as 10 percent due to added drag.


More important, under-inflation puts undue stress on the tire, producing irregular wear at best. At worst, under-inflation causes complete failure that can result in an accident. Abnormal tire flexing occurs when a tire doesn't have enough air, which can generate an excessive amount of heat internally. Too much heat will exceed the tire's capabilities and cause the tire plies to separate or result in a blowout.