My daughter has been riding her two wheeler for close to a year, now. She has a healthy trepidation about riding on, or crossing, "big streets;" and several of her friends have those overpriced "towing wheel" cycles (see the second picture). The kind that can't be used for anything at all if they aren't attached to a grown-up's bike. Well, she wants a towing bike, too.
I'm not about to drop $300 when she has a perfectly usable bike already. Instead, I tried to build a towing rig that can attach to both of our bikes, and can also detach, leaving both bikes fully operational.
|DISCLAIMER This project did not work as intended. The trailing bike is not stable when towed, and falls to the side very easily, even without a rider. I have documented my work for completeness, but the device described here is not safe for use.|
I do intend to keep working on this, and try to find a way to reduce the swivel and sway to make it safe and rideable. If I succeed, I'll update this Instructable accordingly.
Update: It turns out that there's an instructable which discusses modifying a commercial product that does exactly what I'm trying to do here. I need to study that I'ble more, to see if it can help me with my issues here.
The basic idea is simple: connect the two bikes with a rigid bar, with a swivel connection at the front end and a stiff connection (and a locked front fork) at the back. It turns out that the connectors at each end are a b**ch to find.
I spent the better part of a day chasing around shops, trying to find a proper universal joint for the front end. No luck. A few days later, Instructables user moaibob published his Bike Trailer Hitch; exactly what I was looking for!
For the trailing end, mating a pipe to the bike at an arbitrary angle isn't easy. I finally found an "adjustable flange" (McMaster-Carr part #4698T77) used for installing stair and other railings, where you can set the pipe receiver to whatever angle you need.
So now I have a buildable project!
Note to readers: All of the drawings were made using the Unix
xfigprogram on my MacBook. If you would like the original .fig files, please let me know in the comments.