Slick tyre

A slick is a racing tyre with a completely smooth surface. With no grooves, more rubber touches the track and dry grip is at its highest. Slicks are used on circuits and in supermoto racing, normally with tyre warmers to bring them up to working temperature before the session.

Slicks are not legal on public roads and are dangerous in the wet, because nothing clears water from the contact patch. Wet races use rain tyres with deep grooves.

In everyday speech, 'slick' also describes a road tyre worn so far that little or no tread is left. Such tyres must be replaced: the legal minimum tread depth for motorcycles in the EU is generally 1 mm, though more is recommended for wet roads.