Frame for an electric cargo bicycle
A frame for an electric bicycle, such as a long-tail electric cargo bicycle, is described. The bike frame, in some embodiments, includes cross members that connect a rear rack of the bicycle to a head tube of the bicycle via a seat tube of the bicycle. Via the multiple connection points, the cross members mitigate side to side movement, such as waggling, of the rear rack of the bicycle.
1. A frame for an electric bicycle, the frame comprising:
a head tube configured to support handlebars and a front fork;
a seat tube configured to support a saddle post that holds a saddle and is placed at least partially within the seat tube;
a top tube that extends from the head tube to the seat tube;
a down tube that extends from the head tube to the seat tube;
a rear rack that is configured to support a passenger or cargo placed onto the electric bicycle;
two cross members that extend from the rear rack to the top tube,
wherein each cross member extends past the seat tube to the top tube; and
two cross member posts,
wherein each cross member post attaches a cross member to the seat tube;
a dropout assembly configured to support a rear wheel hub of a rear wheel of the electric bicycle;
a chainstay that extends from the seat tube to the dropout assembly;
a seatstay that extends from the seat tube to the dropout assembly; and
one or more vertical support posts that attach to the dropout assembly and extend between the dropout assembly and the rear rack.
2. The frame of claim 1 , wherein the cross members extend from the rear rack to the top tube at an outside position of the seat tube to form an opening between the seat tube, the top tube, and the cross members.
3. The frame of claim 1 , wherein the two cross members are welded to the top tube, the rear rack, and the cross member posts; and wherein the cross member posts are welded to the seat tube.
4. The frame of claim 1 , wherein the cross members attach to the top tube such that the top tube, the seat tube, and the cross members form a triangle in a horizontal plane of the frame.
5. The frame of claim 1 , wherein each of the cross members has a curve between the rear rack to the top tube.
6. The frame of claim 1 , wherein the top tube includes mounting points positioned to mount an accessory to the frame at least partially between the cross members.
7. The frame of claim 1 , wherein the rear rack includes mounting points configured to interchangeably mount foot pegs or a running board to the frame.
8. The frame of claim 1 , wherein the rear rack includes a deck and mounting points configured to interchangeably mount deckhands or a caboose accessory to the frame.
9. A dropout assembly for an electric cargo bike, the dropout assembly comprising:
a horizontal slot that receives a rear wheel hub of a rear wheel of the electric cargo bike;
a top support portion having a cross-sectional geometry that includes an I-beam shape having a lip that extends away from the top support portion,
wherein the top support portion is configured to support:
a chainstay that extends from a seat tube of the electric cargo bike to the dropout assembly; and
a seatstay that extends from the seat tube of the electric cargo bike to the dropout assembly; and
one or more vertical support posts that attach to the top support portion of the dropout assembly and extend between the dropout assembly and a rear rack of the electric cargo bike.
10. The dropout assembly of claim 9 , wherein the top support portion is configured to support two vertical support posts that extend between the dropout assembly and the rear rack of the electric cargo bike.
11. The dropout assembly of claim 9 , wherein the top support portion includes two or more planar support surfaces, and wherein the dropout assembly includes a flat portion, disposed on an outer surface of the dropout assembly and configured to accommodate a torque arm or torque arm washer secured to the dropout assembly.
12. The dropout assembly of claim 9 , wherein the top support portion includes three planar support surfaces.
13. The dropout assembly of claim 9 , wherein the top support portion has a three planar geometry angled to facilitate welding of the chainstay, the seatstay, and the one or more vertical support posts to the dropout assembly.
14. The dropout assembly of claim 9 , wherein the chainstay and the seatstay attach to the top support portion at a front section of the top support portion and the one or more vertical support posts attach to the top support portion at a back section of the top support portion.
15. The dropout assembly of claim 9 , wherein the electric cargo bike is a long-tail cargo bike.
16. A frame for a cargo bike, the frame comprising:
a head tube;
a seat tube;
a top tube; a
a rear rack; and
two cross members that extend from the rear rack to the top tube,
wherein each cross member extends past the seat tube to the top tube without directly attaching to the seat tube, and
wherein the cross members extend from the rear rack to the top tube on opposite sides of the seat tube to form an opening between the seat tube, the top tube, and the cross members.
17. The frame of claim 16 , further comprising:
two cross member posts,
wherein each cross member post attaches one cross member to the seat tube.
18. The frame of claim 16 , wherein the top tube includes mounting points positioned to mount an accessory to the frame at least partially within the opening between the seat tube, the top tube, and the cross members.
19. The frame of claim 16 , wherein each of the cross members has a curve between the rear rack to the top tube.