Instructables
Picture of Bike Trailer Hitch
DSCN4733.JPG
This is a very cheap Hitch made with a swivel caster, a bracket for antenna poles and  a piece of square iron pipe.
To be fixed under the bike saddle.
Great just because it allows the movement on three axes, so there's complete freedom while biking.

 
Remove these adsRemove these ads by Signing Up

Step 1: What you need

Picture of What you need
A swivel caster with bolt. Make sure to buy a wheel that can be removed from the frame, just removing the axle bolt.
A cross bracket for antenna poles
Self-locking nut

Step 3: Assembling

Picture of Assembling
DSCN4718.JPG
DSCN4833.JPG
DSCN4831.JPG
Drill a hole in the middle of one of the hump on the cross bracket. The hole should allow the bolt of the frame of the swivel caster to fit in.
Lock the bolt with the self-locking nut.
If you want, you can cut the exceeding bolt thread with a grinder before assembling.
Using the grinder, shape a piece of square 30x30mm iron pole as shown in the picture, then drill two passing holes, one for each axle, and fix the piece to the wheel frame by the horizontal axle.
The iron piece will allow the vertical movement, the trailer bar that is going to be attached will allow the horizontal movement and the bearing of the wheel frame the torsional movement.
A simple steel pin will be used to fix the trailer bar to the hitch.
That's it
lowbike12 months ago

this is brilliant

kelseymh1 year ago
Thank you again for your help on this! I was able to successfully build your hitch (here's what mine looks like), but I have discovered that it was the wrong solution for my problem. You built this, I think, to pull a cargo trailer, with two or more wheels. That system is self-stabilized, and you need the three axes of freedom at the lead end.

My goal is to tow my daughter's two-wheeler, and in this case those three swivel axes are way too many :-/ Her bike tips over, the towbar wanders all over the place, etc. I've had to back off to using a fixed mount on my seat post, and will come up with a cleaner design than the hack I have right now.
swivel_mount.JPGhitch_mounted.JPG
moaibob (author)  kelseymh1 year ago
Yes, you need a 2 swivel axes, not a three if you don't want to pick up your daughter from the asphalt with a spoon... :-) . But this should be an easier task. If you have a projext already, keep on going, otherwise let me know, I'll try to figure out some easy and unwelded solution....
I got it down to a fixed fitting (with a tightened vertical bolt) at my end, but I haven't done a good job locking the front fork on the trailing bike. I'm going to try a couple of threaded rods down to attachment points at the front axle.
kelseymh1 year ago
I'm working on integrating this nice design into a towbar I'm building. It would be quite helpful if you could add some steps showing the cutting and assembly of the rest of the hitch, in particular how the box beam is cut, and where the axle holes are drilled in the box beam and the trailer bar itself. Did you use sleeve bearings on the two axles, or just bolts?

I'm likely need to order some parts online, so having dimensions would be really helpful. What diameter is your trailer bar? What size box beam did you choose to fit it? What size caster did you need for the box beam to fit?
moaibob (author)  kelseymh1 year ago
Sorry, I have no pics of the ongoing cut but i can take some of the disassembled hitch to show the cut and holes. In the holes i just used bolts but the sleeve bearings could be a good improvement.
About the dimensions, I edited the project adding some pics and comments with dimensions.
Glad to be helpful in your project!
Thank you very much! The additional pictures are very helpful, and the dimensions you quoted match what I was trying to guess from the picture. I just got back from measuring a bunch of casters; it looks like a 3-inch wheel (75 mm) is just wide enough for the 30-mm box beam to fit in the caster housing.

I'm having trouble finding the antenna bracket anywhere. Did you purchase it locally, or online?
moaibob (author)  kelseymh1 year ago
Great!
About the antenna bracket, I bought it at a local hardware store, and they apparently don't sell online. I don't know if you have something similar around your place, but check this link: http://www.leroymerlin.it/catalogo/sicurezza-e-domotica/antenne-e-accessori/giunto-a-croce-33890143-p , you may print this and take it to some hardware store or some antenna installer to get clues.
Thank you! I had posted a Question about this, and user gadget-man pointed me to an alternative:

http://www.amazon.com/Sioux-Chief-516-5GPK2-SIOUX/dp/B004FC6968/ref=pd_sim_sbs_MI_12

It comes with a threaded 3/8" (9.5 mm) hole, which is exactly what the caster uses. Put a jam-nut in between and it'll be solid.
ohmdaddy1 year ago
This is a great idea. I have actually been pondering how to make a hitch and the torsional freedom with the caster is excellent!
zieak1 year ago
This is great. Thank you for sharing it.