Rigid frame with high-compliance seat tube and internal cable routing
A bicycle can include a forward frame triangle that can include a top tube, a bottom tube, a bottom bracket, a structural seat tube, a compliant seat tube, and a pair of seat stays. The top tube can have a first end connected to a head tube and a second end. The bottom tube can have a first end connected to the head tube. The bottom bracket can be connected to the bottom tube. The structural seat tube can be connected to the bottom bracket and the top tube. The compliant seat tube can extend in an upward direction, from the bottom bracket to the top tube and within the structural seat tube. The compliant seat tube can be coupled to the forward frame triangle such that the compliant seat post can bend within the structural seat tube.
1. A bicycle, comprising:
a forward frame triangle comprising:
a top tube having a first end connected to a head tube and a second end;
a bottom tube having a first end connected to the head tube and a second end;
a bottom bracket connected to the second end of the bottom tube; and
a structural seat tube from the bottom bracket to the top tube;
a compliant seat tube extending in an upward direction from the bottom bracket to the top tube and within the structural seat tube;
a pair of seat stays connected to the top tube and extending in a rearward direction beyond the forward frame triangle;
wherein:
the compliant seat tube is coupled to the forward frame triangle such that the compliant seat tube can bend within the structural seat tube; and
the compliant seat tube is coupled to the forward frame triangle by a pivot connecting the compliant seat tube to the forward frame triangle proximate the top tube at a location nearer a bicycle seat than the bottom bracket.
2. The bicycle of claim 1 , further comprising at least one of a pair of bearings or a pair of bushings positioned between the compliant seat tube and the forward frame triangle.
3. The bicycle of claim 1 , wherein the compliant seat tube is made of a fiber reinforced plastic.
4. The bicycle of claim 1 , wherein the compliant seat tube is configured to bend in a longitudinal direction in response to riding forces.
5. The bicycle of claim 1 , wherein the compliant seat tube has an aero-foil cross section.
6. The bicycle of claim 1 , wherein an upper portion of the compliant seat tube extends above the structural seat tube.
7. The bicycle of claim 6 , wherein a cross section of the upper portion of the compliant seat tube matches a cross section of the structural seat tube.
8. The bicycle of claim 6 , further comprising a gasket located between the upper portion of the compliant seat tube and the structural seat tube.