Bicycle frame with open tubes - has seat tube and down tube, opening bottom bracket area, with covers, to carry spares

摘要

The bicycle frame has round or oval tubes, of steel, aluminium, or a synthetic material. The seat tube and/or down tube, are open in the bottom bracket joint. The open tube is closed by a cover. Chain stay and rear stay may also be open. Down tube (4.1) and chain stay (4.3) do not extend to the bottom bracket bearing. The chain stays extend to the point of an auxiliary joint (4.6), and an auxiliary down tube stay (4.8) extends to the bottom bracket joint. Both are open in this area, and carry a hinged lid. ADVANTAGE - Theft proof storage and secure transportation of pump, stand, spares, etc. and easy carrying of bicycle.