Rear wheel suspension system for a bike

A rear wheel suspension system for a bike, the bike including a rear wheel with a maximum radius, the rear wheel defining a center plane perpendicular to a rotational axis of the rear wheel and coincident with a ground contact of the rear wheel when said bike is upright on level ground, the rear wheel suspension system comprising:

• a seat tube,
• a bottom bracket shell defining a rotational axis extending there through in direction transverse to the center plane, said bottom bracket shell forming part of or being securely fixed to said seat tube,
• a left side flexible chainstay and a right side flexible chainstay, extending longitudinally on either side of said center plane, each of said chainstays having a forward end configured for attaching to a lower portion of the seat tube of said bike less than 250 mm from said rotational axis of the bottom bracket shell,
• a left side seatstay and a right side seatstay, each having lower end areas connected to posterior end areas of each of said flexible chainstays, and each of said seatstays extending upwardly and forwardly with an opposite end being configured to extend to a position which is outside of the maximum radius of the rotably attached rear wheel and at a distance from an upper portion of said seat tube of said bike,
• a set of dropouts located where said flexible chainstays and said seatstays interconnect for rotably supporting said rear wheel of said bike, and
• a leaf spring interconnecting said seatstays and said seat tube,
• wherein one end of the leaf spring is connected to the upper end area of said seatstays, and
• wherein the leaf spring extends upwardly from a point of connection to the upper end area of the seatstays to a point of connection to said seat tube of said bike, said leaf spring defining opposite top and bottom surfaces extending transversely to said center plane,
• wherein the said leaf spring is arranged at a distance D to the seat tube in a direction perpendicular to said top and bottom surfaces of the leaf spring to allow flex of said leaf spring towards said seat tube and thus vertical flex of said flexible chainstays,
• wherein the rear wheel suspension system further comprises one or more stiffness adjustment inserts, arranged and secured in place between said leaf spring and said seat tube,
• wherein one or more of said one or more stiffness adjustment inserts are elevatable substantially perpendicularly to said top and bottom surfaces of said leaf spring,
• wherein one or more of said one or more stiffness adjustment inserts are slidable upwards and downwards along and between said leaf spring and said seat tube, said one or more slidable stiffness adjustment inserts being guided to prevent lateral movement,
• wherein the rear wheel suspension system further comprises a linear actuator for sliding one or more of said one or more slidable stiffness adjustment inserts upwardly and downwardly,
• wherein said linear actuator is arranged in a groove that runs up and down the posterior surface of said seat tube, said one or more of said one or more slidable stiffness adjustment inserts have an extrusion shaped to interact laterally with the surface of said groove.

A rear wheel suspension system for a bike, the bike including a rear wheel with a maximum radius, the rear wheel defining a center plane perpendicular to a rotational axis of the rear wheel and coincident with a ground contact of the rear wheel when said bike is upright on level ground, the rear wheel suspension system comprising:

• a seat tube,
• a bottom bracket shell defining a rotational axis extending there through in direction transverse to the center plane, said bottom bracket shell forming part of or being securely fixed to said seat tube,
• a left side flexible chainstay and a right side flexible chainstay, extending longitudinally on either side of said center plane, each of said chainstays having a forward end configured for attaching to a lower portion of the seat tube of said bike less than 250 mm from said rotational axis of the bottom bracket shell,
• a left side seatstay and a right side seatstay, each having lower end areas connected to posterior end areas of each of said flexible chainstays, and each of said seatstays extending upwardly and forwardly with an opposite end being configured to extend to a position which is outside of the maximum radius of the rotably attached rear wheel and at a distance from an upper portion of said seat tube of said bike,
• a set of dropouts located where said flexible chainstays and said seatstays interconnect for rotably supporting said rear wheel of said bike, and
• a leaf spring interconnecting said seatstays and said seat tube,
• wherein one end of the leaf spring is connected to the upper end area of said seatstays, and
• wherein the leaf spring extends upwardly from a point of connection to the upper end area of the seatstays to a point of connection to said seat tube of said bike, said leaf spring defining opposite top and bottom surfaces extending transversely to said center plane,
• wherein the said leaf spring is arranged at a distance D to the seat tube in a direction perpendicular to said top and bottom surfaces of the leaf spring to allow flex of said leaf spring towards said seat tube and thus vertical flex of said flexible chainstays,
• wherein more than 30% of a length of said top and bottom surfaces of said leaf spring is at any given location less than 12° from being parallel to said seat tube of said bike.