In tire size specifications, what does the letter R represent?

In tire size specifications, the letter R stands for "Radial." This designation indicates the construction type of the tire, which is a critical aspect of its performance and durability. Radial tires are designed with layers of fabric arranged at a right angle to the direction of travel, which provides better stability, fuel efficiency, and tread wear compared to bias-ply tires. The radial construction has become the standard in modern tire manufacturing due to these advantages, making it a key factor in vehicle safety and handling. Other terms like "Rim," "Round," or "Reinforced" do not accurately reflect the construction technology of the tire; thus, they hold different meanings or do not relate directly to the specification of tire size.