What is the difference between radial and bias-ply tires?

Radial and bias-ply refer to the construction of the tire. Radial tires have layers of fabric with cords running at right angles to the direction of travel, providing more flexibility and better heat dissipation, which makes them ideal for high-speed riding. Bias-ply tires have layers of fabric with cords running diagonally to the direction of travel, making the tire more rigid but offering a smoother ride, which is often preferred for touring or cruiser motorcycles.