Hi guys, have you ever wanted to design and make your own bike?

Well I have and until 3D printing came along it seemed like only a pipe dream but now it’s possible! I thought I would share the story of how I (and a colleague Alan) created and printed a downhill mountain bike with working wheels and rear suspension using only ABS (no flexible filament was used at all).

I was heavily into mountain biking when I was younger and so when I got my first 3D printer last year one of the first things I thought of printing was a bike. But work and other things got in the way so I only got around to it this year. I had printed a few springs in ABS so I knew I could get the suspension working if I could get the linkage working and make it printable. I really wanted to make it semi functional because I didn’t like the idea of having a bike that looked great but wasn’t capable of doing anything.

I designed the spring and suspension and sent the drawings to Alan (a colleague in the UK) who did the detailed design for me. Then once he sent the design back I had to modify the tolerances and just make a few tweaks here and there to make it 3D printable and to ensure all the snap fits were working. The yellow and red bike is the first prototype and fit together well but did not function as nicely as I would have liked so the green and red design is the second prototype which works much better and fits together great.

I also created a stop motion video of the bike in ‘action’ at our local mountain bike trail, the link to the youtube video is here if you are interested:

I printed it all in ABS (no flexible filament was used) on a Makerbot Replicator 2X, most of the components were done in 2 layers with 10% infill but the spring was 20% (it ended up probably being much higher because the spring was relatively small). I used pretty much standard ABS settings and printer settings but I do run a higher printed bed temperature of 120C to reduce warping of the ABS. All parts were printed with a raft to reduce warping and some were printed with supports. I also put all the parts into an acetone vapour bath to get a smoother and shinier finish. The total print time of all the parts would be approximately 7 hours.

The design is free to download and print from the Trinpy website http://www.trinpy.com/models/miniature-downhill-bike/ A short video of the working bike can be found at the trinpy facebook page (I can’t figure out how to upload videos) https://www.facebook.com/trinpy

I hope you guys like it and if you have any comments or questions then please let me know in the comments.

Cheers

Andrew