Abstract: A bicycle frame including a down tube that is releasably connected to a bottom bracket shell, and a top tube that is selectively rotatable about a portion of the seat tube. The bicycle can selectively be placed into a ridable position when the front portion of the frame aligns with the rear portion of the frame, or selectively rotated into a collapsed position by disconnecting the down tube from the bottom bracket shell and rotating the top tube about the seat tube.

Abstract: A bicycle frame having a replaceable flexible down tube assembly, wherein the down tube assembly includes a resilient arcuate down tube member with connectors in the form of releasable mounting clips removably attached to the ends of down tube member. The clips clamp on transverse mounting pins in stems attached to the bicycle frame at the ends of the down tube assembly. The clips are releasable to remove the down tube assembly from the frame for replacement or substitution of a down tube having different performance or appearance characteristics. The clips are removable from the down tube for separate replacement of clips and the down tube.

Abstract: A bicycle frame having a replaceable flexible down tube assembly, wherein the down tube assembly includes a resilient arcuate down tube member with connectors in the form of releasable mounting clips removably attached to the ends of down tube member. The clips clamp on transverse mounting pins in stems attached to the bicycle frame at the ends of the down tube assembly. The clips are releasable to remove the down tube assembly from the frame for replacement or substitution of a down tube having different performance or appearance characteristics. The clips are removable from the down tube for separate replacement of clips and the down tube.

Abstract: A tube for use in a bicycle frame in which the tube has a first end and a second end, and a middle section extending between the ends. The first end, second end, and middle sections each have oval-shaped planar cross-sections. In the cross-sections of the first and second ends, the height is greater than the width. In the cross-section of the middle section, the width is greater than the height. This arrangement allows the middle section of the tube to flex vertically between it is narrower in the vertical direction. Likewise, this arrangement provides a strong connection point at the first and second ends which resists flex and movement vertically because the tube is thicker in the vertical direction.

Abstract: In accordance with the present invention, an improved bicycle frame according to one embodiment of this invention has a top tube that allows the wheel base to lengthen by resiliently flexing or pivotally deflecting vertically while resisting torsional flex This feature is combined with a resilient, flexible, arcuate down tube extending between the bottom bracket of the bicycle and the bicycle head tube or the intermediate connection points The down tube has at least one arc and springs back to its original position from forces of tension as well as compression The combination of the two flexing members gives the bicycle a smoother ride and may also enhance the delivery of pedal” power to the rear wheel The down tube is replaceable in order to modify the flex characteristics of the frame and physical characteristics, such as head tube and seat tube angle, wheel base, and bottom bracket height.

Abstract: In accordance with the present invention, an improved bicycle frame according to one embodiment of this invention has a top tube that allows the wheel base to lengthen by resiliently flexing or pivotally deflecting vertically while resisting torsional flex This feature is combined with a resilient, flexible, arcuate down tube extending between the bottom bracket of the bicycle and the bicycle head tube or the intermediate connection points The down tube has at least one arc and springs back to its original position from forces of tension as well as compression The combination of the two flexing members gives the bicycle a smoother ride and may also enhance the delivery of pedal” power to the rear wheel The down tube is replaceable in order to modify the flex characteristics of the frame and physical characteristics, such as head tube and seat tube angle, wheel base, and bottom bracket height.

Abstract: In a bicycle frame of the type wherein front and rear portions of the frame are connected together by a flexible spring member, the spring includes at least two laterally spaced, elongated rods extending between opposed mounting blocks in the front and rear portions of the frame, with the ends of the rods being held in the mounting blocks by a clamping mechanism that can be released to permit removal and replacement of the spring members when desired. A replaceable wire management tube is attached to the side of the crossbar of the bike by adhesive tape and extends at least a portion of the length of the crossbar. The bicycle frame can incorporate a folding mechanism that permits the front and rear portions of the bike to be folded together for easy portability of the bike.

Abstract: In a bicycle frame of the type wherein front and rear portions of the frame are connected together by a flexible spring member, the spring includes at least two laterally spaced, elongated rods extending between opposed mounting blocks in the front and rear portions of the frame, with the ends of the rods being held in the mounting blocks by a clamping means that can be released to permit removal and replacement of the spring members when desired. A replaceable wire management tube is attached to the side of the crossbar of the bike by adhesive tape and extends at least a portion of the length of the crossbar. The bicycle frame can incorporate a folding mechanism that permits the front and rear portions of the bike to be folded together for easy portability of the bike.

Abstract: A bicycle frame includes a front frame having a cross bar, a rear frame including a center post, and a leaf-spring-like flexible plate interconnecting the cross bar to the center post. A shock-absorbing member is pivotally secured at its ends to the front end of the cross bar and to the bottom of the center post in a triangular arrangement. The shock-absorbing member includes a coil spring that stores energy as the shock absorber member is extended in a first direction and the frame is expanded, which energy is returned to the bicycle frame upon relaxation of the coil spring. However, the shock-absorbing member is substantially incompressible in the opposite direction so that it prevents the front and rear frames from collapsing undesirably. This also allows forces to be transmitted from the front frame to the rear frame through the shock-absorbing member in the second opposite direction thus taking some stress off of the flexible plate.

Abstract: A bicycle frame having a front frame portion with a rearwardly extending crossbar of elliptical cross-section, the major elliptical axis of which is vertically oriented. The rear of the crossbar is gradually tapered by flattening and widening into a substantially equilateral triangular configuration and then sharply reduced to an oblong horizontally extending opening where it is connected to a rear frame by a flexible spring connection.

Abstract: A bicycle frame has front and rear frame portions interconnected at their top by a flexible spring connection, that allows relative vertical flexing of the frame portions, and by a tension cable and compression spring between a forward portion of the front frame portion and a lower portion of the rear frame portion. Integral stiffening means included with the vertical center post member of the rear frame portion and with the horizontal crossbar assembly of the front frame portion are provided to minimize the tendency of the front portion of the frame to yaw laterally from side to side relative to the rear frame.

Abstract: A bicycle has a front frame portion including a front wheel and handlebars and a rear frame portion including a crank housing, a pedal crank, a rear wheel, and a seat with a flexible fiberglass spring plate removably mounted between upper portions of the front and rear frame portion and a steel cable extending from the crank housing of the rear frame portion to the upper portion of the front frame portion. During operation of the bicycle, the front frame portion can flex with respect to the rear frame portion by flexing the fiberglass spring plate and tensioning the cable against the bias of compression springs holding the cable in tensioned condition. The fiberglass spring plate can be removed and replaced with another plate having different flexibility characteristics for accommodating rider of varying weights.