The invention disclosures a stage-variation variable speeds transmission bicycle, comprising a bicycle bracket, wherein the bicycle bracket is provided with a medial axis, a medial axis chain wheel group is arranged on the medial axis, medial axis chain wheel group comprises three chain wheels with different size; also comprising bicycle rear shaft, a freehub arranged on rear shaft, the freehub is fixed with a sun gear, one side of the sun gear is provided with a planetary carrier comprising planetary gears, a gear ring is provided radially outward of planetary gears, a ratchet is provided radially outward of the gear ring, the ratchet is provided with a pawl, the invention is easy to start and can be operated at a high speed, also can realize switch between the one-stage and two-stage transmission status arbitrarily during riding and parking to ensure a better cycling experience.

An individual chain wheel for a bicycle front crank arrangement for engaging in a drive chain includes a plurality of teeth formed on a circumference of the chain wheel and having a first and a second group of teeth. The teeth of the second group of teeth are arranged in an alternating manner between the teeth of the first group of teeth. Each tooth has a load flank via which force is transmitted between an adjacent roller of the drive chain and the respective tooth. Each tooth of the first group may also have at least one profile with an opening in the vicinity of the flank, in which a portion of an inner link plate of the drive chain, which portion protrudes beyond the roller, engages.

A system and method for simple transmission of a multi-speed bicycle is provided. A bicycle can have a transmission that can be toggled by a kickback shifting mechanism. A rear wheel hub can support a freewheel having a high speed gear sprocket and a low speed gear sprocket with dedicated chains to create dedicated gear-shifting. Rotating the pedal shaft in the non-drive direction approximately one-quarter rotation can toggle the transmission between the first gear ratio and the second gear ratio with a shifting surface that alternately allows driving engagement of the high speed gear sprocket with the rear wheel driver.

A sprocket for engagement with a drive chain has a plurality of teeth extending radially from a periphery of the sprocket, including a first and a second group of teeth; the teeth of the first group and the second group are alternately arranged so that each tooth of the first group is followed by a tooth of the second group, and vice versa; each tooth of the first group having a first maximum width, each tooth of the second group having a second maximum width which is larger than the first maximum width; each tooth of the second group has a protrusion on at least one lateral face of the tooth; the outer lateral face of the protrusion extends over a first portion of the lateral face of each tooth of the second group, the length being 50% of the length of the respective tooth or less.

A sprocket for engagement with a drive chain has a plurality of teeth extending radially from a periphery of the sprocket, including a first and a second group of teeth; the teeth of the first group and the second group are alternately arranged so that each tooth of the first group is followed by a tooth of the second group, and vice versa; each tooth of the first group having a first maximum width, each tooth of the second group having a second maximum width which is larger than the first maximum width; each tooth of the second group has a protrusion on at least one lateral face of the tooth; the outer lateral face of the protrusion extends over a first portion of the lateral face of each tooth of the second group, the length being 50% of the length of the respective tooth or less.

The invention discloses an automatic downshifting and variable speed transmission bicycle, comprising a bicycle stand, wherein the bicycle stand is installed with a bottom bracket; the bottom bracket is installed with a bottom bracket sprocket set, and the bottom bracket sprocket set is composed of three chain discs of different sizes; a rear axle of the bicycle is provided with a tower footing, and the tower footing is fixedly installed with a sun gear; one side of the sun gear is provided with a planet carrier, and the planet carrier is installed with planetary twin gears. The invention is easy to start, can run at high speed, has multiple functions, and is reliable in operation, with convenient maintenance and low cost, and is energy saving and environmental-friendly; it has a good market prospect and brings great convenience to cyclists.

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.

The present invention relates to a bicycle chainring (1) for engagement with a drive chain provided with rollers, the bicycle chainring (1) comprising: a plurality of teeth (2, 3) extending radially from a periphery of the chainring (1), wherein the plurality of teeth (2, 3) comprises a plurality of narrow teeth (3) and a plurality of wide teeth (2), wherein each tooth (2, 3) comprises a front flank (5) and a rear flank (6) with respect to a drive direction (DD) and two opposing side surfaces (9), wherein at least one side surface (9) of each wide tooth (2) comprises a protrusion (7) extending therefrom in an axial direction of the chainring (1), wherein each protrusion (7) comprises a respective groove (8) arranged halfway between a top land (10) of the respective wide tooth (2) and a root circle (11) of the respective wide tooth (2), wherein the groove (8) extends throughout the protrusion (7) in a direction substantially parallel to the top land (10). The invention further relates to a bicycle comprising the of the invention chainring (1).

A drive arrangement for a bicycle may be provided with various interactive components configured to reliably and repeatably engage and disengage with one another both when new and after a period of wear. The drive arrangement may include a drive sprocket assembly connected to a driven sprocket assembly with a chain movable by a gear changer.

A sprocket for a bicycle drive train comprising an outer ring having external teeth for engaging in a bicycle chain, and an inner ring coaxially disposed with the outer ring and is connected to the outer ring in a rotationally fixed manner. The inner ring has a central opening. A circumferential collar is configured to be integral with the inner ring and projects axially to one side of the inner ring and is configured as a continuous collar. An internal profile having a plurality of radially inward-projecting radial protrusions is provided on the radially inner side of the collar, and an external profile having a plurality of radial depressions, which in number and arrangement correspond to the radial protrusions of the internal profile, is provided on the radially outer side of the collar.