Bike Trailer

9th September 2022

I got weirdly obsessed with bicycle trailers a few weeks ago. Not cargo trailers, or dog trailers, but camper-as-in-RV trailers. In practice they seem to mostly be intended to be towed by ebikes due to weight, but some come in at practical-pedal-power weight too.

For some reason this seems to be popular in Germany in particular, so I’ve been watching an inordinate number of YouTube videos in German with closed captioning and using Google Translate to auto-translate to English as I regrettably don’t speak German. (It doesn’t work that well.) In any case, there’s a surprising number of people making their own “Fahrradwohnwagen”s or “FaWoWa” if you suck at German spelling, as I do. If you want a taste, check out this recent meetup!

Many Germans build with Coroplast over aluminum, I think largely due to Paul Elkins and Rene Kreher, and there’s a very deep hole to fall down if you want to explore the intricate details of everyone’s designs and variations and customizations.

Naturally, I decided I need to build my own! There were lengthy unnecessary detours reading and learning about fibreglassing, aluminum metal work, solar panels, insulation, and more. I really like the idea of a “foamie” though. This is a DIY-friendly construction method used for lightweight trailers (but typically not quite as light as bike-towable). It consists of using regular pink foam insulation board as the structure, and then wrapping it in some sort of fibreglassing. The classic foamie uses “PMF” (Poor Man’s Fibreglass) rather than actual glass fibres with epoxy. Instead it uses plain cotton canvas, a specific type of water-resistant wood glue, and then a specific recipe of exterior latex paint to create what is by most accounts a surprisingly robust and durable exterior finish.

After an embarrassing amount of time in SketchUp coming up with convoluted fancy designs I realized if I wanted to learn about all these under-documented (or German-documented!) techniques I really should start as simple as possible, and so my “design” for a Brutalist Bike Trailer (as in the architecture style, but realistically also pretty brutal to spend time in). It’s basically a box with wheels, air holes, a door, and a window, and I’m not sure about keeping the window.

Today was the first day I had some time to try some actual work on it in the garage. It went very badly, during ripping the first piece of wood, I realized the table saw fence wasn’t working and was up to my arms in sawdust, WD-40, and rust for the next 5 hours. It can only get better from here.

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