In the P225/60R16 tire size designation, what does the 'R' stand for?

In the tire size designation P225/60R16, the letter 'R' indicates that the tire has a radial construction. Radial tires are constructed with cords that run perpendicular to the direction of travel, typically arranged in layers beneath the tread. This design helps distribute forces evenly across the tire, improving stability, handling, and fuel efficiency.

Radial construction has become the standard in modern tires due to its benefits, such as reducing rolling resistance and providing a smoother ride. It also contributes to improved grip and wear characteristics compared to bias-ply tires, which use a different construction where the cords are arranged at angles to one another.

Understanding this designation is critical when considering tire performance and compatibility with vehicles, as radial tires are designed to work effectively with modern suspension systems and wheel alignments.