SCHALT-TRETKURBELTRIEB FUER FAHRRAEDER

摘要

A gear crank for a bicycle includes a plurality of chain gears mounted to stays disposed radially outwardly with respect to a crank shaft. The stays include four main stays arranged in pairs. The two main stays forming each pair are disposed at a relative phase difference of about 180 DEG . Two short auxiliary stays are disposed between the pairs of main stays and have mounting portions for the larger diameter chain gears. The pairs of main stays intersect at a non-90 DEG angle so that an angle between the pairs of main stays is larger than that between the main stays forming each pair. The stays are fixed to the crank to position the crank arms between the pairs of stays within a region defined by the above-described larger angle respectively. Connecting segments extending circumferentially and supporting the auxiliary stays are provided between the auxiliary stays and the main stays adjacent thereto respectively.