First of all a warning: this is for towing a bicycle only, not for towing a bicycle with a rider on it.

This bicycle appendage allows towing of another bike. It is made from the rear end of a Mixte frame, because these frames have a suitable geometry to get the mounting point nice and low for the front fork of the towed bike, which makes it track better through corners.

The closer the head tube is to vertical, the better it will track. Therefore the mount point for the towed bike's fork should be as low as possible.

Step 1: Make the Frame From a Mixte Frame Rear Triangle

A Mixte frame rear triangle has 3 tubes meeting at each rear dropout. One of these tubes is removed, and the other ones are cut to length. In my case, I cut one tube at 200mm and the other at 400mm from where the mounting point is (the axle). Make two of these - one from each side of the Mixte frame.

Step 2: Make the Rotating Mount

A rotating mount is fitted into each dropout. This is where the front fork of the towed bicycle mounts, and is secured with a nut. These rotating mounts were made from 5/16-inch axles, wheel bearing cups, cones and bearings, though they could probably be made without the bearings, simply with the bearing cones acting as bushes inside the hole in the dropout. They don't need to turn that well; in fact it's better that they have resistance so the towed bike doesn't bounce too much - resistance acts as a dampener.

Step 3: Make Attachments to Bolt Onto the Frame

These rack arm extensions were fitted into the end of the tubes, which were then squashed flat and bolted in place. Then the whole assembly was mounted onto the frame. The bolt securing the V-brake was used as one of the mounting points. This doesn't interfere with the braking.

Finally, a heavy duty cable tie was used to brace the assembly to the rack, giving it extra strength and stability.

Step 4: Mounting and Towing a Bicycle

Here are some shots of a bicycle being mounted onto the tow-bike, with the front wheel stowed on the front rack and tied off to the bar ends with pedal straps.

In this way a bicycle can be towed with relative ease by the tow-bike, when the need arises...

Remember, this is for towing a bicycle only, not for towing a bicycle with a rider on it.