I did some more work on the swing bike.
To get an idea of what a swing bike is do some google searches for “swing bike” or “wobble bike”. Basically it is a style of wacky bike that is generally made as a goofy project. Most of the bikes I have seen are structurally weak designs and/or have rear headsets that are welded in place. My friend Tim had one of these bikes but as you could expect it failed with not much more then light real world use.
The following is an example that *might* work for a day but will not stand up to real use. I did not build this bike and frankly would be afraid to ride it.
Our goal in this project is to make a swing bike that will stand up to real world use.
The complex part of my design is to make the swing bike strong and also allow the rear headset to be serviced. This requires that the swing tube be designed so it can be disassembled and as such I needed to fabricate some parts.
I still need to make three more parts but the fundamental design is complete.
In this design the bulky hardware and all bolts are down low so the ugly parts are out of view. The swing tube separates and goes together. The welding is at the normal locations for the seat-top tube joint and the bb-downtube joint. The segmented swing tube is beefy fork steerer tube plus reinforced by the pin so it should not flex much and it would amaze me if it ever broke mid-tube like Tim’s old bike.
With enough force this design will likely fail near one of the weld points but once again this is beefy tubing and welded on butted sections plus the forces in these areas should not be much different from a normal bicycle.
