Lightweight bicycle tyre, comprising a lightweight inner tube (latex or butyl) completely enclosed in a woven nylon, cotton, or silk carcass with a light rubber tread. The carcass is sewn up around the inner tube and the stitching covered by a base tape, normally glued on. The tyre is cemented (using liquid rim cement, double sided "tub tape" or, in extreme cases, shellac) to the "sprint" type of wheel rim, which has a box section with a lightly concave outer surface and deep recesses for the spoke nipples. The fitting and adhesion are critical; "rolling a tub" while riding generally results in you and others around you hitting the tarmac pretty hard.
The difficulties involved in fitting, removing and repairing this type of tyre - the carcass must be opened up and restitched in order to repair a puncture - mean that its use is now restricted to road, track and cyclo-cross racing; wire-beaded open-sided (British English "high pressure", American English "clincher") designs using new materials, particularly Kevlar beading, now run them close in terms of weight and performance with a much lower maintenance burden. In the absence of a team car carrying spare wheels, the only thing that can be done if you puncture on tubulars is to fit a spare tyre (traditionally carried rolled up under the saddle, or, in the days when even riders in the Tour de France had to carry their own spares, wrapped in a figure-8 around their shoulders) using the residual adhesive on the wheel, pump it up very hard and ride carefully to ensure that it does not roll off the rim.
The leading manufacturers of tubulars still in business are the Italian-based company Vittoria (whose CX model was the canonical road racing tyre for a couple of decades) and Germany's Continental; others include Soyo from Japan and Hutchison in France. Earlier names that have now dropped this market niche include Clément (latterly part of Pirelli), Dunlop and Czechoslovakia's Barum.
Colloquial names used: "sew-ups" or "tubies" (American) and "tubs" (British).