1st attempt

My first attempt at a bike frame was to make a 5" travel trail bike out of fibreglass over balsa wood and aluminium.

The idea was to create a do-it-all bike that could be easily taken apart into parts to fit in a regular suit-case allowing you to take a bike on holiday without having to faff about with oversized baggage. It was also designed around 24" wheels (which I found could just about fit into a large suitcase).

At this point I had no access to welding equipment so I took the decision to attempt to use composites to make a frame. Obviously carbon fibre would be the ultimate material to use but for a first attempt I tried fibreglass.

The basic premise was to use aluminium tubing for the seat post and head tube, bottom bracket shells for the main BB and also for the swingarm pivot, and surly drop-outs (which combine the drop-outs, mech hanger and rear disk mount), glued to a balsa-wood frame core. This would make it very easy to make the basic layout of the frame using only hand tools. Aluminium sheet would then be glued over the top of the balsa wood core where serious strength is needed. Finally fibreglass goes over the top to bind everything together and provide structure.

This is what it looked like with the core and alu sheeting assembled:

And the finished article:

And what it looked like after I tried to ride it:

It seems my design had a bit of a flaw... In trying to design a swingarm that gave maximum crank clearance (and was as simple as possible to fabricate) I had made something that had about as much structural integrity as a dandilion. I went back to the drawing board...