A wheel support portion for a bicycle, such as a front fork assembly, arranged to reduce vibrations that originate at the bicycle wheel and are transmitted to the rider of the bicycle through the wheel support. Desirably, the front fork assembly is configured to be supported by a bicycle frame and includes a pair of fork legs, which extend in a downward direction along opposing sides of a front wheel of the bicycle. Preferably, the fork legs are configured to support the front wheel at their low...

Power control circuitry and method for controlling a variable output DC power source. The power control circuitry may include a first comparator to compare a signal representative of an output current level of the variable output DC power source with a threshold level and provide a first output signal in response to the comparison. The power control circuitry may further include threshold input circuitry to provide the threshold level to the first comparator, the threshold level being a fixed th...

A junction for the head tube of a bicycle frame with top tube and down tube members is fabricated in such a way that the top tube and down tube members are jointed. The method of mitering the top tube and down tube members to form the requested joint is cutting off a portion of walls of both the top tube and down tube members at the head ends to form a miter joint. The method of mitering provides for optimum contact area and ease of manufacturing, especially for tubes with non-traditional cross-...

A constant-voltage circuit includes a first transistor, a first control circuit, and a second control circuit having a second transistor and a differential amplifier. The first transistor controls an output current according to a first control signal output by the first control circuit such that an output voltage is substantially equal to a predetermined voltage. The second control circuit has a response property faster than the first control circuit to a variation of the output voltage, and cau...

A tube connection assembly of a bicycle frame includes a bi-forked portion formed by a hollow rectangular tube; one end of the rectangular tube being bi-forked as two halves; each half having a positioning groove; and a combining portion formed by two plates which are connected as a shape corresponding to that of the positioning groove and the bi-forked portion so that in assembly the combining portion is assembled to the bi-forked portion; and connection area of the bi-forked portion and combin...

A constant-voltage circuit includes a first transistor, a first control circuit, and a second control circuit having a second transistor and a differential amplifier. The first transistor controls an output current according to a first control signal output by the first control circuit such that an output voltage is substantially equal to a predetermined voltage. The second control circuit has a response property faster than the first control circuit to a variation of the output voltage, and cau...

Power control circuitry and method for controlling a variable output DC power source. The power control circuitry may comprise a first comparator to compare a signal representative of an output current level of the variable output DC power source with a threshold level and provide a first output signal in response to the comparison. The power control circuitry may further comprise threshold input circuitry to provide the threshold level to the first comparator, the threshold level being a fixed ...

A low noise voltage regulator circuit with fast stable output voltage is disclosed. The low noise voltage regulator circuit contains a reference voltage generator, for generating a reference voltage; a switching circuit, which is electrically coupled to the output of reference voltage generator and has two states; and a stabilizing circuit. When the switching circuit is at a first state, the reference voltage is coupled to the stabilizing circuit without being filtered; when the switching circui...

A seat tube for a bicycle includes an upright tube, a head and an inner tube all of which are made of fiber reinforced material. The upright tube has an inserting portion at a top thereof. The head has an inside chamber and a sleeve portion at a bottom thereof. The sleeve portion of the head is sleeved onto the inserting portion of the upright tube such that the inside chamber of the head is communicated with an inside of the upright tube. An outer wall of the inserting portion of the upright tu...

Disclosed are motorcycle frame assemblies comprised of carbon fibers. Methods of making the disclosed motorcycle frame assemblies are also disclosed. In one aspect, the frame assembly of the motorcycle comprises a structural member that includes an engine compartment member, which is adapted to receive an engine on a portion of an inner surface of an opening defined within the engine compartment member. In one further aspect, the structural member comprises a carbon fiber material.