Plastic Square Tube Caps for Bike Trailer Hitch

thingiverse

This is a series of plastic tube-caps with holes in it for a steel trailer hitch on a bike. The idea is that you fabricate a seat-post mounting hitch as shown in the photo or similar, and then print a set of these tube caps to shove into the ends of the 1.5 x 1.5 x .065 inch wall square tube section. You then slide it over your seat post to pull a bike trailer or trail-a-bike (in this case the hitch was made for a Trek Mountain Tram). The caps are specifically designed for 1.5 x 1.5 x .065 inch wall square tube. I've included solidworks files and parasolids if you want to modify it for some other size... for me this worked well because it had enough room between the seat tube on a 31.9 mm seat post and the wall of the tubing without going to a larger square tube size. I've included 28, 32, and 33mm holes because that's what I wanted for my purposes. Again, feel free to download the solid models and remix to suit your needs. Material: I made mine from PLA, but would recommend something a little tougher and less prone to cracking. ABS or NYLON would be good choices.