A two wheel tandem vehicle is propelled by hand-grasped poles. A front wheel on a forward member and a rear wheel on a rearward member align along a longitudinal axis. The forward member pivots about a substantially vertical steering axis. A saddle and footholds support the rider and together with an accessory contact means allow the rider to balance and steer the device. The rider's hands do not contact the vehicle but are used to propel the vehicle with the poles.

The present invention discloses an installation structure for a wheel axle assembly and a wheel fork, a frame and a vehicle. The wheel axle assembly includes a wheel axle; a first bearing, a bush and a second wheel axle sleeved on the wheel axle successively; and a hub arranged on the outer rings of the first bearing and the second bearing, wherein the bush is used for spacing apart the first bearing and the second bearing axially a predetermined distance, and the hub is of a sleeve shape and an end thereof arranged on the first bearing expands the outer diameter to form a flange portion for fixing and installing a wheel; and the wheel fork includes a wheel fork body and a frame connection portion formed on an end of the wheel fork body and forming an L shape with the wheel fork body for connecting to a frame, and the wheel axle is fixed on the other end of the wheel fork body in a direction perpendicular to the rim center plane of the wheel.

In an aspect, a compactable bicycle is provided, comprising a base frame portion and a steering structure. The base frame portion includes a seat tube and a head tube, a connecting tube connecting them and a rear frame portion that has a rear wheel mounted thereto. The steering structure includes a steering member rotatably mounted in the head tube, a handlebar, and a front wheel support having a front wheel connected thereto. The steering member includes first and second portions that are removably connectable together. The head tube includes first and second portions that hold the first and second steering member portions respectively. The second head tube portion is movable relative between a first position in which the first steering member portion is superjacent to the second steering member portion, and a second, stowage position.

Described herein is a bike including a frame member linking the front and rear wheel(s) made up of a first forward section or sections extending from the front wheel(s) and a second rear section or sections extending from the rear wheel(s). The section endings mate about a lockable connection assembly that is also in communication with a seat-post connected to the seat. The frame sections pivot about a connection assembly axis in a direction perpendicular to the bike frame and the seat-post is able to be moved independent of the frame sections. A key advantage of the above bike is the high range of height adjustability allowing the bike to be used by range of different sized users. Height adjustment is also very easy and may be done toolessly. Further, maintaining the seat in a desired riding alignment independent of frame movement is important otherwise the rider position will change relative to the handlebars leading in extreme cases to falls from the bike. Use of gas assisted injection molding in bike manufacture is also described.

A two-wheeler vehicle comprising a steerable front wheel of at least 16 (d.sub.f), a fixed back wheel smaller than or equal (d.sub.b) to df. A distance between the back wheel ground contact point and the front wheel contact point is smaller than or equal to (12+V(d.sub.f d.sub.b). A steering mechanism defines a steering axis ground contact point. A trail distance between the steering axis ground contact point and the front wheel ground contact point is between 5% and 10% of the df. The steering mechanism comprises a fork, a yoke and a handlebar. A frame interconnects the yoke and the center of the back wheel and comprises a standing mechanism providing at least one footboard, below the back wheel center, extending laterally from the frame.

A two-wheeler vehicle comprising a steerable front wheel of at least 16 (d.sub.f), a fixed back wheel smaller than or equal (d.sub.b) to df. A distance between the back wheel ground contact point and the front wheel contact point is smaller than or equal to (12+V(d.sub.f d.sub.b). A steering mechanism defines a steering axis ground contact point. A trail distance between the steering axis ground contact point and the front wheel ground contact point is between 5% and 10% of the df. The steering mechanism comprises a fork, a yoke and a handlebar. A frame interconnects the yoke and the center of the back wheel and comprises a standing mechanism providing at least one footboard, below the back wheel center, extending laterally from the frame.

A lever driven bicycle with synchronous drive ratio control is disclosed. The lever driven bicycle may include a pair of drive levers pivotable around an axis. The lever driven bicycle may also include a force applicator connected to each drive lever, each force applicator configured to receive an application of a force to rotate a drive wheel. The lever driven bicycle may further include a control mechanism connected to the pair of drive levers, the control mechanism configured to synchronously adjust a drive ratio of each drive lever.

A pedal-propelled transmission mechanism, applied in a workout equipment; the workout equipment including a deck, a front tube fixed at a front end of the deck, and a handle fixed on a top end of the front tube; the pedal-propelled transmission mechanism comprising a driving chainring having a center axle pivotally connected to a proximity of a rear section of the deck, a left pedal mechanism, and a right pedal mechanism, whereby the structure of the pedal-propelled transmission mechanism is simple that reduces the production cost and time, and easily repair and change when the parts are broken.

A pedal-propelled transmission mechanism, applied in a workout equipment; the workout equipment including a deck, a front tube fixed at a front end of the deck, and a handle fixed on a top end of the front tube; the pedal-propelled transmission mechanism comprising a driving chainring having a center axle pivotally connected to a proximity of a rear section of the deck, a left pedal mechanism, and a right pedal mechanism, whereby the structure of the pedal-propelled transmission mechanism is simple that reduces the production cost and time, and easily repair and change when the parts are broken.

The present invention discloses an installation structure for a wheel axle assembly and a wheel fork, a frame and a vehicle. The wheel axle assembly includes a wheel axle; a first bearing, a bush and a second wheel axle sleeved on the wheel axle successively; and a hub arranged on the outer rings of the first bearing and the second bearing, wherein the bush is used for spacing apart the first bearing and the second bearing axially a predetermined distance, and the hub is of a sleeve shape and an end thereof arranged on the first bearing expands the outer diameter to form a flange portion for fixing and installing a wheel; and the wheel fork includes a wheel fork body and a frame connection portion formed on an end of the wheel fork body and forming an L shape with the wheel fork body for connecting to a frame, and the wheel axle is fixed on the other end of the wheel fork body in a direction perpendicular to the rim center plane of the wheel.