A shock-absorbing frame structure for bicycle includes a front frame unit formed of a head tube, a down tube, a seat tube, and a top tube, a bottom forks unit pivoted to the front frame unit, and a shock-absorbing device coupled between the front frame unit and the bottom forks unit, the seat tube having a seat pillar for holding a saddle and a top end for holding a seat back, the bottom forks unit including two bottom forks, and a connector connected between the bottom forks at a front side and pivoted to a bottom lug at the front frame unit, a cross tube connected between the bottom forks on the middle, an upward lug formed integral with the cross tube to support the shock-absorbing device, and an arched frame rod bridging the bottom forks at a rear end for the mounting of a luggage-carrier and a rear fender.

An improved bicycle seat includes a seat base having a base plate and a seat cushion mounted on the base plate and a seat base mounting shaft mounted on and extending downwards from the base plate of the seat base. A seat back mounting shaft assembly is mounted on and extends rearwards and upwards from the seat base mounting shaft and the base plate of the seat base and a generally upright seat back is adjustably mounted on the seat back mounting shaft assembly for vertical and horizontal adjustment of the positioning of the generally upright seat back relative to the seat base. The seat cushion further includes a generally flat front face and a forwardly tilted top surface wherein the top surface of the seat cushion is forwardly tilted from horizontal between two and thirty degrees.

A strength-saving steering mechanism for bicycles includes a H-shaped tube with a vertical insert pipe deposed at the inner end of a bar pipe of the H-shape tube. The vertical insert pipe is inserted in one upper end of a steering shaft pipe, which connects to a front wheel. The H-shaped tube is further equipped with a hollow vertical pipe and connected pivotally to an inside tube through an upper and a lower bearing. A vertical handle rod is inserted internally in one upper end of the inside tube and a positioning block is connected to one lower end of the inside tube. The steering shaft pipe is driven by a horizontal handle rod via the vertical handle rod and the connecting rod. Ratios of turning angles of the horizontal handle rod and the vertical handle rod exist for saving the strength.

A ergonomic tandem bicycle suitable for riders with some limited physical capabilities. The ergonomic tandem bicycle includes an elongated frame with an angled steering column attached to the front portion that positions the front wheel substantially in front of the frame, and the handlebars towards the rear. A transmission assembly includes the necessary pedal sprockets, along with idler sprockets that maintain continuous contact between the sprockets and the long drive chain required with this type of design. The seat is positioned in such a manner so as to allow the riders to sit in a near vertical position.

A recumbent bicycle designed to be flexible in its geometry, adjustable in wheel base, position of seat, position and angle of front fork steering head tube mechanism, lead of front wheel bearing position on front fork, and/or position of foot pedal crank mechanism, allowing ergometric optimization for riding ease, comfort, stability, safety, etc. The unique aspect of the present invention is that the relationship between the bicycle seat and the rear wheel can be ergonomically optimized, and then the positioning of other elements can be optimized for the individual rider without altering the rear wheel to rider relationship.