Which component of tire construction does not have additional belts?

The component of tire construction that does not have additional belts is the diagonal ply. In tire construction, a diagonal ply design features layers of fabric that are placed at an angle to the tire's direction of travel. This construction does not incorporate an additional belt system, which distinguishes it from other types of tires.

In contrast, radial ply tires consist of radial plies that are reinforced by belts, typically made from materials such as steel, which provide strength, stability, and support. Belted bias tires have a bias-ply construction that also includes belts to enhance performance and durability. The term "all tires have belts" is not accurate, as it erroneously implies that every tire design includes belts, which is not the case with diagonal ply tires.

This clarity on the design characteristics of each type helps in understanding their applications, advantages, and limitations in various driving conditions.