There are two types of trailer tires: Radial and Bias. A radial tire has steel belts that are oriented at a significantly different angle than the 90 degree radial plys. This allows the sidewall and tread to function as two independent features of the tire. A bias tire consists of multiple rubber plies over lapping each other at a 30-45 degree angle. The tread and sidewalls are interdependent because all plys have a consistent angle. The overlapped plies form a thick layer that is less flexible which makes it able to carry a heavier load and less trailer sway. You will typically have a smoother ride, lower noise, better handling and traction with a radial, which is why you find them exclusively on passenger cars.
Bias tires are typically used for local use: construction, agriculture or utility. Radial tires are often seen on longer distance trailers like RVs, marine and livestock trailers.
