The invention relates to a bicycle gearing, comprising: a cylindrical-gear gearing (10), which has a stationary sun gear (11) having a central bearing axis (y.sub.1) extending centrally therein and a planet gear (12), which travels on the sun gear (11) and rotates about a planet-gear bearing axis (y.sub.2); a four-bar linkage (20), which interacts with the cylindrical-gear gearing (10) and which comprises a crank (21), which is fixedly connected to the planet gear (12) and is rotatably connected to a pedal crank (22); and a toothed wheel (30), by means of which a traction means (31) can be driven. The problem addressed by the invention is that of improving a bicycle gearing of the type in question in such a way that a rounder pedaling feel is perceived by the bicycle rider. The problem is solved according to the invention in that the toothed wheel (30) has an oval shape.

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 cycle crankset, comprising independent cranks articulated around a crank axis and each having a pedal axis, a cam pivotably mounted about the crank axis, and a chainring assembly pivotably mounted about the cam about an axis parallel to the crank axis, the cranks being connected to the chainring assembly via connecting rods, the articulation point between each of the cranks and one of the connecting rods being located on the portion of the crank opposite the pedal axis relative to the crank axis.

A cycle crankset, comprising independent cranks articulated around a crank axis and each having a pedal axis, a cam pivotably mounted about the crank axis, and a chainring assembly pivotably mounted about the cam about an axis parallel to the crank axis, the cranks being connected to the chainring assembly via connecting rods, the articulation point between each of the cranks and one of the connecting rods being located on the portion of the crank opposite the pedal axis relative to the crank axis.

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.

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 crank assembly for a bicycle includes a crank axle rotatably mounted to a frame of the bicycle, and a carrier shaft slidably mounted on the crank axle and configured to slide in a direction substantially parallel to a central longitudinal axis of the crank axle and relative to the crank axle. The crank assembly also includes an elliptical sprocket mounted on the carrier shaft. The elliptical sprocket rotates to move the bicycle in response to a rotation of the crank axle. A start time of a power stroke of the elliptical sprocket is changed by sliding the carrier shaft relative to the crank axle.

In order to form a largely oval circulatory path, in particular a pedal (1a), a crank drive (1) is described which periodically changes the effective lever length of a crank (2). In this case, gear levers (4 or 7) are mounted on a crank (2) at both ends (2 a, 2b) which rotate in opposite directions with respect to one another and thus form two further movement axes within the pedal path and are thus adapted to the natural human leg movement in a force-saving and ergonomic manner.

In order to form a largely oval circulatory path, in particular a pedal (1a), a crank drive (1) is described which periodically changes the effective lever length of a crank (2). In this case, gear levers (4 or 7) are mounted on a crank (2) at both ends (2 a, 2b) which rotate in opposite directions with respect to one another and thus form two further movement axes within the pedal path and are thus adapted to the natural human leg movement in a force-saving and ergonomic manner.

A bicycle with a rear drive assembly configured to allow pedal boards to be pivotable while moving in an elliptical trajectory and which allows a cyclist to ride in an erect position is disclosed. A front end of each of the pedal boards is pivotably connected to an end of a crank and each of the pedal boards is connected to or integral with a guide rod extending rearwardly from the pedal board. The guide rods are supported by a rear drive assembly comprising a transverse tube that is horizontally connected to a frame of the bicycle. A roller is mounted at each end of the transverse tube. Each roller has a groove which accommodates the cross-section of the guide rod.