Knobby Tyre

A knobby tyre, or knobbly, has a tread made of separate raised rubber blocks (knobs) with open spaces between them. The knobs bite into loose surfaces such as dirt, mud, sand and snow, while the gaps let mud clear out as the wheel turns.

Knob height, spacing and rubber compound are matched to the terrain: tall, widely spaced knobs suit soft mud and sand, while lower, closer knobs and harder compounds suit hardpack and rocky ground. Off-road-only tyres are not road legal; dual-sport and enduro tyres with E-marking can be used on the road but wear faster on tarmac.

Run the pressure recommended for the terrain, check for torn or rounded knobs, and replace the tyre when the edges of the knobs are worn round.