Bias ply and radial ply trailer tires differ in construction, performance, and intended use.
Construction
Bias ply: Multiple rubber plies that overlap at a 30–45° angle
Radial: Steel belts that run at a 90° angle to the tread centerline
Performance
Bias ply: Less performant on curves, more susceptible to abrasion and heat
Radial: Smoother ride, better traction and stability, less tread wear, and run cooler
Intended use
Bias ply: Good for infrequent or short-route trailers, rough or unpaved roads, and slower speeds
Radial: Good for longer, faster runs, and use with travel trailers on paved roads
Other considerations
Bias ply tires are usually less expensive than radial tires
Radial tires have a more durable construction
Bias ply tires have a stronger sidewall
You can tell if a tire is radial by looking for an “R” in the tire size printed on the sidewall
The right tire for your trailer depends on your needs and conditions. A bias ply tire is built with a 30 to 45-degree cord angle to the center line of the tire.A radial tire is built with cord at 90 degrees to the tire's centerline. The 90-degree construction allows for more surface contact with the radial while the bias tire rides more on the center crown of the tire.