Technical Dictionary

Durometer

An instrument used to measure hardness. Specific to tyres, a durometer typically measures the hardness of the tread compound. Durometer can also refer to the hardness result, as in The tyre’s durometer is 60.

High Flotation Sizing System for Light Trucks

Tyres with lower sidewalls and wider treads that yield better traction on surfaces such as sand and soft soil found in watery, off-road situations.

High Modulus Undertread™

Layer of rubber below grooves that anchor the tread blocks to the casing plies for increased grip, steering response, and optimal handling.

High-performance tyres

Also called maximum performance, ultra-high-performance, etc., offer a superior degree of handling, grip, and cornering ability than standard tyres. High-performance tyres are also rated for operation at higher speeds than non-high-performance tyres.

Highway tyres

Also called summer tyres; designed for wet-and-dry weather driving, but not for use on snow and ice.

Hysteresis

When rubber stretches and compresses, it does not render all the energy applied to it because energy is lost due to internal friction. The mechanical energy is transformed into thermal energy and the heat produced leads to both damage and energy loss.