Racers and cyclocrossers like to ride on tubular tyres. Tubular tyres are referred to as such because the inner tube is sewn directly into the bicycle tyre, thus forming a single unit. Tubular tyres are glued into the rim base with tubular cement. In the event of a puncture, the inner tube must be removed from the rim and can then be opened. Special tubular tyre repair kits are available for these cases.