Hitch parts - bicycle frame guard
The bicycle frame guard consists of a 3" section of 1/2" automotive heater hose that is slit lengthwise so it can be fit over the rear seat or chain stay of the towing bicycle. A 3" x 3/4" piece of aluminum chip with a 1" radius fits over the hose piece and under the attaching U bolts. This spreads the force of the clamping U bolts so they do not cut into the rubber.
The hose is standard heater hose available from most automotive supply stores. A 3" piece is cut from the hose and slit alongside one side. The aluminum chip is manufactured from 1" aluminum tube that is machined about 3/4" wide and 3" long.
The PH13 is a component part of the PH23 bolt on hitch mount.