Homemade Bicycle Trailer Made From a Backpack Frame

An old external frame from a backpack makes a great bicycle trailer frame. With a bit of aluminum conduit and a few parts from the local hardware store, nearly anyone can make a bicycle trailer from a backpack. According to Russell Kramer, a designer on Appropedia.org, a sturdy trailer can be built from used materials, such as a backpack and a few old bicycle parts, that will haul most any load and provide a sustainable way to transport items around town.

  1. The Frame

    • Use the backpack frame--without the pack attached--as the main portion of the frame, but then build two wheel wells on either side of the frame. The wheel wells can be built by bolting two small rectangles of metal tubing to each side of the frame. The wheels fit inside the rectangles, suspended by their axle bolts. Tie the entire frame together by attaching the backpack frame to the wheel wells with two conduit crossmembers. Assemble all of the pieces together with wing nuts and locking washers/bolts. This ensures that if you want to disassemble the frame for storage or transport you can do so easily. Mount two 20-inch bicycle wheels in the wheel wells with their axle bolts.

    The Tongue

    • Once the trailer frame is assembled it is time to make the tongue that attaches the trailer to the rear of the bicycle. The tongue is made by bending a long piece of conduit into a “lazy S” shape to extend from the bicycle seat post down to the front of the trailer. You want the trailer to sit nearly level when it is attached to the back of the bicycle, so make sure the angles on the tongue are sufficient to accommodate this feature. You can purchase a conduit bending tool from the hardware store or simply use the crook of a tree to achieve the appropriate bend angles. Once the tongue is bent, attach it to the frame with a wing nut and bolt. Drill a hole in the end of the conduit to act as the hitch receiver.

    The Hitch

    • Develop a hitch for the rear of the bicycle seat post. The hitch is simply a secure connection that allows a full range of movement. The easiest way to accomplish this is to attach a climbing carabiner to the rear of the post with hose clamps. Make sure the hook end of the carabiner is facing the ground and mount the tongue of the frame to the hitch by opening the carabiner and sliding it through the hole in the end of the conduit. This allows the trailer to move freely, but also ensures a secure lock for the trailer.