A drive train for a human-powered vehicle comprises a drive unit, a sprocket arrangement, and a total gear range quotient. The drive unit includes a motor configured to impart propulsion to the human-powered vehicle. The sprocket arrangement is operatively coupled to the drive unit. The sprocket arrangement comprises a plurality of rear sprockets and a plurality of gear ratios respectively corresponding to the plurality of rear sprockets. The plurality of gear ratios includes a largest gear ratio and a smallest gear ratio. The total gear range quotient is obtained by dividing the largest gear ratio by the smallest gear ratio. The total gear range quotient is larger than 5.

A gear (10) for a bicycle transmission (20) is described, having an external contour (11) with teeth (12a, 12b) formed thereon, wherein the external contour (11) is defined by a maximum pitch diameter (.sub.max) and a minimum pitch diameter (.sub.min), does not have any axes of symmetry and is formed exclusively with point symmetry with respect to its centre of symmetry (M). The invention was therefore based on the problem of developing a gear (10) which improves the pedaling feel of a bicycle transmission (20). The problem is solved in that the external contour (11) exhibits a change in its curvature at every point.

A bicycle crank assembly with adjustment orientation system for ovoid toothed chainrings comprising a right crank arm (2) provided with a fifth torque transmission profile (211); a shaft (1) provided with a second torque transmission profile (121) which is non-rotatably engaged to said fifth profile (211); and a transmission element (3), for incorporating toothed chainrings, provided with a fourth torque transmission profile (301) to non-rotatably engage with the first torque transmission profile (120) of the shaft (1). So, when combining the N2 angular positions provided by the coupling between the right crank (2) and the shaft (1) with the N1 angular positions provided by the coupling between the transmission element (3) and the shaft (1), Nt different relative angular positions between the right crank (2) and the transmission element (3) are obtained, thus increasing the possible orientations and decreasing the angular increment between consecutive orientations of the crank assembly.

A transmission structure for a bicycle includes two opposite transmission units. Each of the transmission units includes a linear reciprocating pedaling mechanism, a transmission module which is in transmission connection with the linear reciprocating pedaling mechanism, and a resetting module connected with the transmission module. The transmission modules of the two transmission units are connected with a power output mechanism through a unidirectional transmission mechanism. The transmission module includes a first driven wheel and a first transmission gear configured to be coaxial with the first driven wheel. The resetting module includes a connecting piece and an elastic piece. The connecting piece is connected with the first transmission gear. The elastic piece is connected with the connecting piece.

A ride-along vehicle may include a guard that attaches to a bottom portion of a molded plastic body and covers a spring and chain assembly. The guard may also provide an attachment point for the spring through a hole in the guard. The guard may have a narrow portion that covers and helps retain the chain on a sprocket as well as a wider portion that covers the spring. An improved pumper arm and steering mechanism may include a pivot joint that is provided by rods, pins, or bolts attached to opposite sides of the pumper arm. The universal joint between the steering arm and the pumper arm can be aligned with the center of the pivot point to prevent rocking of the steering arm as the pumper arm is actuated.

The present invention relates to an asymmetric elliptical chainring for a clipless pedal, wherein a slope at each imaginary point of a first to second elliptical section increases counterclockwise, a slope at each imaginary point of a third elliptical section decreases counterclockwise, a virtual center line in a longitudinal direction of a crank arm is located so as to have a set angle in the counterclockwise direction from a starting point of the first elliptical section, the starting point of the first elliptical section is the shortest distance from a center of an asymmetric ellipse, has a curve of a first set curvature or less, and forms a first angular section from the starting point of the first elliptical section, a start point of the second elliptical section meets an end point of the first elliptical section located within a first near transition section, the end point of the second elliptical section is the longest distance from the center of the asymmetric ellipse, a curvature of the second elliptical section is equal to or less than the first set curvature, the second elliptical section forms a second angular section from the starting point of the second elliptical section, a starting point of the third elliptical section is an end point of a second near transition section located between an end point of the second elliptical section, and a curvature of the third elliptical section is equal to or less than the first set curvature and forms a third angular section from the starting point of the third elliptical section.

A ride-along vehicle may include a spring/chain guard that covers a spring and chain assembly and provides an attachment point for the spring. The guard may have a narrow portion that covers and helps retain the chain on a sprocket as well as a wider portion that covers the spring. In another embodiment, the spring can be connected to a fulcrum that has a chain retention pulley, gear, guide, or wheel that keeps the chain tight in loop to improve the pump-action operation of the vehicle. An improved pumper arm and steering mechanism may include a pivot joint that is provided by rods, pins, or bolts attached to opposite sides of the pumper arm. The universal joint between the steering arm and the pumper arm can be aligned with the center of the pivot point to prevent rocking of the steering arm as the pumper arm is actuated.

A bicycle crank assembly with adjustment orientation system for ovoid toothed chainrings comprising a right crank arm (2) provided with a fifth torque transmission profile (211); a shaft (1) provided with a second torque transmission profile (121) which is non-rotatably engaged to said fifth profile (211); and a transmission element (3), for incorporating toothed chainrings, provided with a fourth torque transmission profile (301) to non-rotatably engage with the first torque transmission profile (120) of the shaft (1). So, when combining the N2 angular positions provided by the coupling between the right crank (2) and the shaft (1) with the N1 angular positions provided by the coupling between the transmission element (3) and the shaft (1), Nt different relative angular positions between the right crank (2) and the transmission element (3) are obtained, thus increasing the possible orientations and decreasing the angular increment between consecutive orientations of the crank assembly.

A gear (10) for a bicycle transmission (20) is described, having an external contour (11) with teeth (12a, 12b) formed thereon, wherein the external contour (11) is defined by a maximum pitch diameter (.sub.max) and a minimum pitch diameter (.sub.min), does not have any axes of symmetry and is formed exclusively with point symmetry with respect to its centre of symmetry (M). The invention was therefore based on the problem of developing a gear (10) which improves the pedaling feel of a bicycle transmission (20). The problem is solved in that the external contour (11) exhibits a change in its curvature at every point.

A drive train comprises a sprocket arrangement and a force-transmission coefficient. The sprocket arrangement includes a plurality of rear sprockets and a plurality of gear ratios respectively corresponding to the plurality of rear sprockets. The plurality of gear ratios includes a largest gear ratio and a smallest gear ratio. The sprocket arrangement includes at least one individual sprocket-space provided between two adjacent rear sprockets among the plurality of rear sprockets. The force-transmission coefficient is obtained by dividing a total gear range quotient by a total number of the at least one individual sprocket-space. The force-transmission coefficient is equal to or larger than 0.97 and is equal to or smaller than 1.36. The total gear range quotient is obtained by dividing the largest gear ratio by the smallest gear ratio.