How to Build a Sidecar

Design the frame of your sidecar, either on paper or using a CAD program. Take into account the weight of the passenger you'll be carrying and design the frame to support that weight. Ensure that there is a space for the wheel and a place to attach the pivot, the bar that holds the sidecar next to the bicycle, that is a foot away from the sidecar so that your leg has ample room to move while pedaling.

Cut the lengths of steel you need for the frame and weld them together according to your design. Drill a hole in the exact center of the wheel side and bolt the wheel to the frame. Pick up the frame by the pivot and walk your sidecar around your driveway a few times to ensure that the frame is stable and that it will not wobble. Set the pivot down on a surface that makes it perfectly level.

Design the body of the sidecar. Taper the design in the front to create better aerodynamics. Cut out the pieces of your sidecar body out of plywood. Use wood glue and nails to secure the pieces together tightly, and leave the body for a few hours to set. While waiting for the glue to dry, drill a series of holes in the frame to bolt the body securely when it is attached.

Fill in any gaps on the body with Bondo and sand it smooth. Once the Bondo has set, paint the sidecar and let the paint dry. Bolt the body to the frame and attach the sidecar to your bicycle. Take your sidecar for a test-ride without an occupant. Make sure that the wheel is secure and the body is firmly attached to the frame.