It’s time for new trailer tires and one of your decisions is whether to purchase bias or radial tires.
That decision generally boils down to whether price is most important, or whether you are more concerned about how the tires handle on the road.
Bias tires are less expensive. Trailer owners sometimes say that because trailer tires are followers, that is, they follow behind the vehicle that pulls them, better performance is not as critical as it would be for the vehicle that pulls the trailer. The vehicle in the front does all the fancy work, while the trailer in the back mostly just rolls forward.
Radial tires, however, do perform better than bias tires, and that performance is quickly noticeable.
The ride is smoother, the trailer does not bounce and sway as much, and radial tires have a longer life.
The most important characteristic of any trailer tire is its ability to carry a heavy load. In the past, bias tires were known to carry heavier loads than radial tires. That has changed. Nowadays, radial trailer tires are designated with the “ST” label in their name, short for Special Trailer, and they are built to carry heavy loads. If you have been using bias tires for years because of their load capacity, you might consider taking a look at ST radial tires.
Tire Construction (and what it means to the driver)
Bias and radial tires are constructed differently, and they are manufactured with different materials.
Bias ply tires are made with alternating diagonal layers of rubberized nylon or polyester netting laid down in at a 30 to 45 degree angle to the center-line of the tire. Fiberglass belts are usually added to enhance strength.
Bias Tire Characteristics:
- Bias tires are less expensive than radial tires.
- Bias tires can carry heavy loads.
- Bias tires do fine when going in a straight line, but they do not perform well on curves. That’s because the pressure of the load pushes down on the tires and changes their shape on the road.
- Bias tires are also susceptible to abrasion and heat because of the shape change.
Radial tires are made by overlapping polyester cords at a 90 degree angle to the center line of the tire, then strengthened with steel mesh belts.
Radial Tire Characteristics:
- Radial tires provide a smoother, quieter ride.
- Radial tires track the pulling vehicle well, so there is better sway control on curves.
- Radial tires run cooler because their steel mesh dissipates heat, which reduces the chance of a blowout and adds to the life of the tire.
- Radial tires have a wider footprint, which spreads out tread wear and also adds to the life of the tire.
- Radial tires are more resistant to punctures.
- Radial tires provide better fuel economy because they have less rolling resistance.
- Modern ST radial tires are reinforced and designed for heavy loads.
Bias or Radial?
It is clear that radial tires perform better and have a longer life than bias tires. However, bias tires cost less, and even though they have to be replaced more often, many trailer owners don’t consider that important because they don’t use their trailers very often anyway.