Abstract: A bicycle rear derailleur includes a base member including a mounting portion configured to be attached to a bicycle frame, the mounting portion having a mounting opening through which a central axis of a hub axle passes in a mounting state of the bicycle rear derailleur. The mounting portion includes a single joint or is free of any joint. Also included is a movable member movably coupled relative to the base member and a linkage structure operatively connecting the movable member to the base member. Also included is at least one of a motor, a first wireless communication unit, and an electrical connector. The at least one of the motor, the first wireless communication unit, and the electrical connector are disposed on at least one of the base member, the movable member, and the linkage structure.

Abstract: An axle bearing carrier assembly having a swing arm of unitary construction that operatively associates with an adjustable tension plate for selectively connecting one of two different types of axle bearing carriers to the swing arm.

Abstract: A bicycle derailleur comprises a unit mounting portion, a wireless communicator, an electrical connector receiving portion, and a power supply portion. The wireless communicator is disposed at the unit mounting portion. The electrical connector receiving portion is configured to receive a connector. The power supply portion is configured to receive electricity from a battery disposed at a location apart from the bicycle derailleur.

Abstract: A bicycle electrical front derailleur is provided that basically includes a wireless communication unit, a movable member and an electrical actuation unit. The wireless communication unit is configured to wirelessly receive a control signal. The electrical actuation unit is configured to move the movable member according to the control signal, the electrical actuation unit including an electrical actuator having an output shaft extending downwardly in a state where the bicycle electrical front derailleur is mounted to a bicycle.

Abstract: A bicycle electrical rear derailleur is provided that basically includes a wireless communication unit and an electrical port. The wireless communication unit is configured to wirelessly receive a control signal. The electrical port is configured to be detachably connected to an electrical cable.

Abstract: A bicycle electrical component assembly is basically provided with a bicycle electrical component, a power supply unit and a power supply bracket. The bicycle electrical component includes a movable member and an electrical actuation unit. The electrical actuation unit includes an electrical actuator that is operatively coupled to the movable member to actuate the movable member. The power supply unit is electrically connected to the electrical actuation unit to supply an electrical power to the electrical actuation unit. The power supply bracket is configured to mount the power supply unit to the bicycle electrical component. At least one of the power supply unit and the power supply bracket includes at least one of an electrical cable and an electrical port that is configured to be connected to an electrical cable.

Abstract: A motorized foldable scooter has a frame, at least a front and rear wheel connected to the frame, a seat supported by the frame, a steering arrangement for the front wheel, and an electric motor, driving the rear wheel through a transmission. The frame has at least front and rear frame parts movably connected through a substantially vertical rotary axis to move the frame parts between an extended position of use and a collapsed resting position. The steering arrangement and the seat, and/or the front and rear frame parts are shaped such with respect to each other and the rotary axis that they at least partly nest in lateral direction of the scooter when the frame parts are in the collapsed resting position.

Abstract: An electrically powered vehicle, for example a motorcycle. Disclosed is a vehicle (1) having a rider saddle (7) and a vehicle frame (10) having two frame profiles (11) extending up to a steering head (5) spaced away from each other and the vehicle (1) comprising at least one front wheel (3) guided at a front wheel guide (2) of the vehicle frame (10) and at least one rear wheel (17) guided at a rear wheel guide (13) and the vehicle having a electrically operated drive motor (30) as well as an electrical energy storage device (16) and a drive motor controller (41) and that between the drive motor (30) and a driving wheel a drive train is provided and that the energy storage device (16) is mountable between the frame profiles (11) above the drive motor (30) and the energy storage device (16) is releasably defined at a drive unit (28) mounting the drive motor (30).

Abstract: A chain drive is provided with an engine hanger bolt. The engine hanger bolt is located in a direction rearwardly in a vehicle-body longitudinal direction and upwardly of a drive sprocket and extends in a vehicle width direction to fix an engine block to a body frame. A guide tube is mounted coaxially with the engine hanger bolt and restricts upward displacement of a drive chain.

Abstract: A motorcycle having a head pipe, a vehicle body frame including a pair of left and right main flames extending rearward from the head pipe, and an engine below the vehicle body frame and including a cylinder having an inclined cylinder axis, and an intake device. The intake device has an air cleaner box above the engine and the main frames; a throttle body provided with throttle bores and a valve shaft penetrating the throttle bores, the throttle body is located on a rear side of the engine between the pair of left and right main frames and guides intake air from the air cleaner box to the engine; and a measuring device located on a rear side of the throttle body which rotates about a rotational shaft parallel to the valve shaft to measure a throttle operation amount.

Abstract: A chain drive is provided with an engine hanger bolt. The engine hanger bolt is located in a direction rearwardly in a vehicle-body longitudinal direction and upwardly of a drive sprocket and extends in a vehicle width direction to fix an engine block to a body frame. A guide tube is mounted coaxially with the engine hanger bolt and restricts upward displacement of a drive chain.

Abstract: To provide a rear portion structure of a saddle-type vehicle, which enables securement of a space for arranging vehicle-mounted components on the upper side of a drive chain at a position apart from a pivot shaft. A motorcycle includes a rear wheel swingably provided on a main member via a swing arm, a drive chain entrained about a driven sprocket provided on the rear wheel and a drive sprocket, and a seat frame. An air-exhaust pipe extends from an engine on a lower portion of the seat frame, an extending portion extends rearward of the vehicle from the seat frame, and a chain guide roller is mounted on the extending portion.

Abstract: A motorcycle with a muffler disposed downwardly of a rider's seat positioned, in a side view, upwardly of a rear wheel when a rear shock absorber is extended, to minimize sideway bulging of the muffler from a vehicle body and improve ride comfort, while avoiding interference between the muffler and other parts. An outer shell of a muffler has a rhombus cross section. The muffler is disposed on at least one side in a vehicle width direction of a rear wheel wherein one pair of side walls extend in parallel with each other out of side walls of the outer shell extending in a vertical direction. A side cover is formed to extend along the upper and outer side walls of the four side walls of the outer shell to cover the muffler from a side, downwardly of a rider's seat.

Abstract: A transmission 20 includes an input shaft 12, an output shaft 13, a primary sheave 23 that rotates together with the input shaft 12, a secondary sheave 24 that rotates together with the output shaft 13, and a belt 25 wound around both the primary sheave 23 and the secondary sheave 24. The transmission 20 includes a motor 22 that shifts a transmission ratio by driving a movable sheave 23a of the primary sheave 23. A control device (ECU 5) of the transmission 20 includes a secondary sheave rotation speed sensor 28 that detects rotation of the belt 25, and a control portion 55 of the ECU 5 performs a sheave position control (normal control of the transmission ratio) after rotation of the belt 25 is detected after starting.

Abstract: To provide a rear portion structure of a saddle-type vehicle, which enables securement of a space for arranging vehicle-mounted components on the upper side of a drive chain at a position apart from a pivot shaft. A motorcycle includes a rear wheel swingably provided on a main member via a swing arm, a drive chain entrained about a driven sprocket provided on the rear wheel and a drive sprocket, and a seat frame. An air-exhaust pipe extends from an engine on a lower portion of the seat frame, an extending portion extends rearward of the vehicle from the seat frame, and a chain guide roller is mounted on the extending portion.

Abstract: A chain adjustment apparatus for a motorcycle includes a substantially C-shaped adjustment recess formed in an end piece member attached to a rear end portion of a rear fork. An adjustment member is slidably fitted in the adjustment recess. The adjustment member includes a projecting member having a substantially V-shaped projecting slope, and a recessed member having a substantially V-shaped recessed slope. The projecting member fits in the recessed member. When a wheel axle is passed through the adjustment member and the end piece member, the projecting member is brought into wedged engagement with the recessed member by axial force on the wheel axle, and upper and lower split bodies of the recessed member are moved, and pressed onto upper and lower face walls of the end piece member for increasing a coupling rigidity of the adjustment member with the end piece member.

Abstract: A motorcycle is provided that includes a drivetrain. The drivetrain includes a transmission having a transmission output shaft and also includes a gearcase coupled with the transmission output shaft. The gearcase has a gearcase output shaft. The transmission output shaft is rotatable in a first direction and the gearcase output shaft is rotatable in a second direction that is opposite the first direction.

Abstract: In some preferred embodiments, the dry clutch is capable of suppressing transmission of engine rotational fluctuations from the engine to a rider via a vehicle body. In the dry clutch including a driving member (clutch shoe) 66 and a driven member (clutch drum) 62 configured to be engaged with each other and disengaged from each other in a non-lubricating atmosphere to transmit/intercept the motive power of the engine to a drive wheel, a solid lubricant 70 is interposed between the driving member 66 and the driven member 62.

Abstract: The preferred embodiments of the present invention allow for easy shift-down and adjustment of a shift-down amount. According to some examples, a transmission (20) includes an electronically controlled transmission mechanism (21), and a control unit (5) that controls the transmission mechanism (21). The control unit (5) includes a transmission ratio control portion (55), a shift mode selection portion (52) that can select an AT mode and that shifts to a shift-down permission mode when a shift-down permission signal (101) is output in the AT mode, and a shift-down operation amount computation portion (51) that computes a shift-down operation amount based on a vehicle state of a motorcycle (1). The transmission ratio control portion (55) shifts down the transmission ratio of the transmission (20) based on the shift-down operation amount when a throttle (70) is operated in the shift-down permission mode.

Abstract: A motorcycle includes a frame and a flexible drive member. The frame is provided with an aperture. An engine is attached to the frame and is configured to selectively rotate a drive sprocket. A driven sprocket is attached to a rear wheel. A flexible drive member operably couples the drive sprocket and the driven sprocket and, in doing so, passes through the aperture in the frame. Methods of manufacturing a motorcycle are also provided.

Abstract: A motorcycle is provided that includes a frame and an engine supported by the frame. The motorcycle also includes a continuously variable transmission operatively driven by the engine and a reduction gearset operatively driven by the continuously variable transmission. The motorcycle further includes a rotatable rear wheel operatively, indirectly driven by the reduction gearset and a swing-arm assembly pivotably mounted, at a forward end thereof, on the frame. The swing-arm assembly is coupled, at a rear end thereof, to the rear wheel. The swing-arm assembly includes first and second elongated and laterally spaced fork members. The reduction gearset set is positioned forward of the rear wheel and laterally between the first and second fork members.

Abstract: A motorcycle includes a frame and an engine supported by the frame. A continuously variable transmission is operatively and indirectly driven by the engine and is supported by the frame. A rotatable rear wheel is operatively and indirectly driven by the continuously variable transmission, which is generally vertically oriented.

Abstract: An all terrain vehicle includes a caliper bracket that moves with the movement of a rear axle by the rotation of an eccentric hub. The eccentric hub rotatably supports the rear axle in a position eccentric to the radial center of an axle supporting section. The caliper bracket includes a range specifying section or, specifically, a first engaging portion, which engages with the rear arm, for specifying the rotating range of the eccentric hub according to the position of engagement with the rear arm. The rear arm includes a second engaging portion that engages with the first engaging portion.

Abstract: A power unit for a motorcycle includes an internal combustion engine having a crankcase rotatably supporting a crankshaft with an axis located on a split face between an upper case half body and a lower case half body and a continuously variable transmission having a belt. Two types of respective different oils for an internal combustion engine and for a continuously variable transmission are used while the rigidity of the crankcase is enhanced. A crankcase is provided with a partition wall that separates between a crank chamber housing a crankshaft and a continuously variable transmission chamber housing a continuously variable transmission. An axial line of the crankshaft and respective axial lines of the drive pulley and the driven pulley are each located at a corresponding one of apexes of an imaginary triangle on a view projected on a plane perpendicular to the axial line of the crankshaft.

Abstract: The present invention provides a vehicle including a frame, a rear wheel, a swingarm coupling the rear wheel to the frame, and a pivot shaft assembly rotatably coupling the swingarm to the frame. The pivot shaft assembly includes a first shaft having a non-circular outer surface engageable with a corresponding non-circular aperture in the frame. The pivot shaft assembly also includes a second shaft threaded to one end of the first shaft. The second shaft pivotably supports one side of the swingarm with respect to the frame. The pivot shaft assembly further includes a third shaft threaded to the other end of the first shaft. The third shaft pivotably supports the other side of the swingarm with respect to the frame.

Abstract: In some preferred embodiments, the dry clutch is capable of suppressing transmission of engine rotational fluctuations from the engine to a rider via a vehicle body. In the dry clutch including a driving member (clutch shoe) 66 and a driven member (clutch drum) 62 configured to be engaged with each other and disengaged from each other in a non-lubricating atmosphere to transmit/intercept the motive power of the engine to a drive wheel, a solid lubricant 70 is interposed between the driving member 66 and the driven member 62.

Abstract: To provide a power unit capable of contributing to simplifying the procedure for fitting the electric motor for speed change use and the starter motor to shorten the motor wiring to facilitate the wiring and for concentrating the mass. A power unit includes a unit case which is journaled in a front part to a pivot shaft and a belt-driven continuously variable transmission is provided together with an internal combustion engine. An electric motor for transmission and a starter motor are provided together and supported by the unit case. The electric motor and the transmission are arranged to be adjoining each other on the same side as the pivot shaft in a side view. The electric motor for transmission is arranged in a position closer to the pivot shaft than the starter motor.

Abstract: A motorcycle includes a frame and an engine supported by the frame. A continuously variable transmission is operatively and indirectly driven by the engine and is supported by the frame. A rotatable rear wheel is operatively and indirectly driven by the continuously variable transmission, which is generally vertically oriented.

Abstract: A motorcycle is provided that includes a frame and an engine supported by the frame. The motorcycle also includes a continuously variable transmission operatively driven by the engine and a reduction gearset operatively driven by the continuously variable transmission. The motorcycle further includes a rotatable rear wheel operatively, indirectly driven by the reduction gearset and a swing-arm assembly pivotably mounted, at a forward end thereof, on the frame. The swing-arm assembly is coupled, at a rear end thereof, to the rear wheel. The swing-arm assembly includes first and second elongated and laterally spaced fork members. The reduction gearset set is positioned forward of the rear wheel and laterally between the first and second fork members.

Abstract: The attachable power device for a bike comprises a base plate installed in an upper side of the rear wheel; a motor and a decelerator which are installed in one side of an upper side of the base plate; an inner casing which includes a power supply unit for supplying power to the motor and is detachably attached to the other side of an upper side of the base plate; an outer casing which is configured to accommodate the inner casing, the motor and the decelerator and is engaged to an upper side of the base plate; a chain sprocket which is installed in a left side of the hub of the rear wheel; a connection member which connects the chain sprocket and the driving sprocket of the decelerator; and a control unit which is installed in the handle and controls a driving of the motor.

Abstract: A tension-adjusting mechanism for adjusting tension on an endless loop member associated with a driven transmission gear is operable to adjust the tension of an endless loop member on a vehicle. The tension-adjusting mechanism is made compact to reduce weight of the vehicle. In particular, the rear end of an arm of a frame rear fork includes an elongated adjustment slot, and one end of an axle, passed through the adjustment slot, is supported by a slider. The rear end of the fork is provided with a projecting portion on a front side relative to the slider, and a tension-adjusting bolt is threadably engaged with a threaded hole provided in the projecting portion.

Abstract: A belt type continuously variable transmission for a vehicle such as a motorcycle includes a primary sheave and a secondary sheave each having a pair of flanges axially movable relative to each other. A belt is wound around the sheaves. An actuator controlled by a control device moves the flanges. The control device includes a determination section for determining whether the actual gear ratio of the belt type continuously variable transmission has become a predetermined gear ratio for TOP or LOW, and a first correction section for correcting an operation amount of the actuator based on the determination made by the determination section. Control accuracy in a region where the gear ratio is TOP or LOW is thereby improved.

Abstract: A control system for an electronically controlled continuously variable transmission of a straddle type vehicle in which an intentional shift down operation is easily made in an AT mode. An MT mode temporarily selecting section makes the gear change mode selecting section select the MT mode temporarily and makes the gear ratio control section change the gear ratio of the transmission to a gear ratio from among a plurality of predetermined gear ratios that is positioned lower than a current gear ratio when a mode change signal is inputted in AT mode. An AT mode returning section returns the gear change mode selected by the gear change mode selecting section to AT mode when a release signal is outputted after MT mode is temporarily selected by the MT mode temporarily selecting section.

Abstract: To place an electric motor, which composes a groove width adjustment mechanism, away from a heat source so that the electric motor can be cooled actively, and to improve both the protection and the maintainability of the electric motor. A primary sheave 113 and a secondary sheave 123 each forming a V-groove with a variable width for receiving a belt are provided. A case 105 for housing the primary sheave 113 and the secondary sheave 123 is formed with an opening 110 for sucking and exhausting air into and out of the case 105. An electric motor 140 for driving a groove width adjustment mechanism 141 for the V-groove of the primary sheave 113 is disposed in an airflow path outside the case 105.

Abstract: A bicycle crank speed change sprocket module includes a fixed star gear having a ratchet around its internal periphery, at least two planet gears and two chains pivotally coupled and axially disposed on both sides of a plate, and the plate is driven to rotate by a crank pedal, and the fixed star gear is engaged to the ratchets on the internal periphery of the planet gear and acted by the planet gear for a faster rotation; a freewheel sprocket freely and rotably coupled to the axle of the crank pedal and disposed proximate to the two chain wheels; and a ratchet disposed on the external periphery of the freewheel sprocket, a chain wound thereon, and the chain is engaged by at lest one chain gear, so that the rotary speed of the chain is much faster than that of the crank pedal for a speed change effect.

Abstract: The invention provides a device for stretching a transmission chain which is closed in itself and is made up from a number of adjacent links which are, in the longitudinal direction of the chain, mutually intercoupled by pairs of longitudinal rocker elements and in which the ends of at least one rocker element operate torque transmittingly with the pulley sheaves of a 5 pulley sheave transmission, said device comprising at least two supporting surfaces lying at a distance of each other and supporting the chain according to an arc, and provided with means to generate in this chain a tensile force leading to a surpassing of the limit of elasticity of the link material. To improve the stretching and more particularly to prevent an uncontrolled bending of 10 the rocker elements during the treatment of the chain with all drawbacks thereof the invention proposes that at least one of the supporting surfaces is configured to support the radial inner area of at least a part of the chain.

Abstract: A steering arm for a walkie/rider truck which has a truck body, a driving motor and load bearing means, a platform for the operator and a steering rod. Button portions extend adjacent both lateral surfaces of the horn of a steering above the grip portions and extend approximately parallel to the lateral surfaces and are supported for pivoting movement approximately about horizontal axes. The button portions are arranged such that they can be actuated by the thumb or the index finger of the hand engaging the associated grip portion.

Abstract: A saddle-type vehicle has an engine unit with a continuously variable transmission. The transmission has a primary sheave and a secondary sheave that are connected by a flexible transmitter such as a belt. The primary sheave, the secondary sheave and the belt are positioned in a transmission case. A starting kick shaft is positioned on the same side of the engine unit as the transmission case but the starting kick shaft is positioned outside of a profile of the transmission case when the engine unit is viewed from a lateral side.

Abstract: A motorcycle is described which has a frame and a rear wheel attached to a driven pulley. A drive pulley is rotatably mounted to a rigid bracket attached to the frame such that a relative orientation between the drive pulley and the driven pulley is maintained substantially constant. A drive belt is coupled to the drive pulley and the driven pulley such that a rotation of the drive pulley imparts a rotation of the driven pulley. A transmission output gear is attached to an output of a transmission, and a drive coupler is provided as an interface between the transmission output gear and the drive pulley.

Abstract: A motorcycle having two drive chains. The gearbox output includes a left front sprocket and a right front sprocket. The rear wheel includes a left rear sprocket and a right rear sprocket. Left and right chains connect the respective front and rear sprockets. Power is transmitted to the rear wheel symmetrically. The swingarm is not subjected to asymmetric force that would twist it or pull it to one side, and can be made lighter. Swingarm flex can be better specified, making the swingarm a more useful suspension component, especially aiding the rear wheel while bent over in hard cornering over an irregular road surface.

Abstract: A motorcycle includes a frame, and an engine and transmission mounted to the frame. A swingarm is pivotably mounted to the frame, and a rear wheel is rotatably mounted to the swingarm. An output shaft of the transmission is coupled to the rear wheel to cause rotation of the rear wheel under power of the engine. A stationary tensioner is mounted to the frame such that as the rear wheel bounces up and down with respect to the frame, the tensioner maintains substantially constant tension and belt path length in the belt without requiring the tensioner to move in a translational or pivotal sense.

Abstract: A motorcycle includes a swing arm defining a drive member aperture through which a flexible drive member extends. During normal operation of the motorcycle, the drive member and swing arm are interlocked due to a portion of the drive member being captured in the drive member aperture. A portion of the swing arm is removable from the rest of the swing arm to open the drive member aperture and permit removal of the drive member as a continuous unbroken loop without the need to drop the motorcycle's transmission.

Abstract: A drive hub configured to mount to the spokes of an off-the-shelf spoked wheel on a vehicle such as, for example, a bicycle, so as to allow said wheel to be driven by a motor mounted to the frame of the vehicle. The hub has an outer face including a channel or belt track for engaging a drive belt from the motor, and the inner side of the hub has formed therein spoke slots configured to accept and lock upon spokes situated on the front or rear wheel of the bicycle, and are situated such that the hub is self-centering upon installation, namely, when all of the slots are lined up to engage spokes on the bicycle, the hub is appropriately centered on said wheel. Each spoke slot is of a width so as to accept an individual spoke, with there being provided ridges, notches or the like in each slot for engaging and locking about the spoke to resist removal of the hub from the wheel, once mounted thereupon.

Abstract: A single-track motor vehicle with an internal combustion engine having at least one cylinder which is arranged in an inclined manner approximately horizontally relative to the driving direction, with at least one intake valve being arranged above at least one exhaust valve. In order to achieve the most compact possible design, the exhaust valve is triggered by way of a rocker lever.

Abstract: A transmission system provided for a bicycle, including a primary transmission sub-assembly having a set of rear sprockets, whose number of teeth, from one sprocket to the next sprocket in the ascending order, varies according to a ratio of the numbers of teeth that is greater than or equal to a value n such as n greater than 1. The invention also includes a control of the transmission system, as well as a bicycle that includes the transmission system and the control for same. The transmission system includes a single chain wheel for driving the chain, associated with a bottom bracket assembly, and a secondary transmission sub-assembly having at least two drive output ratios, whose ratio of the highest drive speed to the lowest drive speed is equal to a value R between 1 and n so as to introduce at least one intermediate transmission ratio between two successive sprockets.

Abstract: An all terrain vehicle comprises an engine that powers a chain or belt operated final drive. The final drive comprises an drive sprocket and a driven sprocket. The driven sprocket is capable of pivotal movement relative to the engine. In one arrangement, the driven sprocket is mounted to a rear portion of a swing arm. The swing arm is pivotally mounted to a frame assembly of the vehicle. A guide member is mounted to the swing arm and is pivotally mounted to the frame assembly. The guide member is laterally displaced from bearings used to journal the swing arm for pivotal movement.

Abstract: A motorcycle includes a frame, and an engine and transmission mounted to the frame. A swingarm is pivotably mounted to the frame, and a rear wheel is rotatably mounted to the swingarm. An output shaft of the transmission is coupled to the rear wheel to cause rotation of the rear wheel under power of the engine. A stationary tensioner is mounted to the frame such that as the rear wheel bounces up and down with respect to the frame, the tensioner maintains substantially constant tension and belt path length in the belt without requiring the tensioner to move in a translational or pivotal sense.

Abstract: An all terrain vehicle includes an engine and a final drive assembly. The engine includes an output shaft that supports a drive sprocket or pulley. The final drive assembly comprises an input shaft that supports a driven sprocket or pulley and a brake disc. A flexible transmitter such as a belt or a chain connects the drive sprocket or pulley and the driven sprocket or pulley. The final drive assembly is formed separate of the engine and spaced apart from the engine when the two components are mounted to a frame of the vehicle. The driven sprocket or pulley is positioned on an upper portion of the final drive assembly while a lower portion of the final drive assembly is pivotally connected to the frame. The final drive assembly can be pivoted to adjust a tension level within the flexible transmitter. The final drive assembly can be selectively secured in a pivotal position by a support rod and/or a set of slotted brackets.

Abstract: Projections colliding with constricted portions at the center of hourglass-shaped pin link plates and with constricted portions at the center of hourglass-shaped roller link plates are provided at an annular resilient body. When a roller chain starts to mesh with a sprocket, constricted portions at the centers of hourglass-shaped link plates of the roller chain can be pushed radially outwards from the sprocket by the projections of the resilient body, vibrations occurring at the roller chain meshing with the sprocket can be made small, vibrations at each part of the roller chain can be made small, collision speed when rollers of the roller chain collide with teeth bottoms of the sprockets can be reduced, and the generation of noise can be suppressed. Moreover, because hourglass-shaped link plates are used, the roller chain can be made lighter than when flat oval shaped or oval shaped link plates are used.

Abstract: A chain roller for supporting a chain when a rear wheel is lowered a given distance or more is mounted to a body frame. The chain roller is elastically deformable. The chain roller includes a hard rubber or hard resin roller having a plurality of axial holes like a lotus root. When a depression load of the chain acts on the roller, the roller is elastically deformed with the axial holes being depressed, thereby relaxing tension of the chain. In a modification, a shock absorber is provided between the body frame and a roller supporting member to relax the tension, or a roller supporting member having elasticity is mounted to the body frame to relax the tension. The absorptivity of displacement and shock can be easily improved with a simple structure.