What makes tires hard?

Tires are made hard through the use of specific rubber compounds that include materials like carbon black and silica, which enhance durability and resistance to wear. The curing process, or vulcanization, involves heating the rubber with sulfur, which creates cross-links between polymer chains, resulting in increased strength and rigidity. Additionally, the tire's design, including its tread pattern and overall construction, contributes to its hardness and performance characteristics. This hardness is essential for providing stability, handling, and longevity on various surfaces.