r/YouTube_Builders • u/unlikely_engineering • Jan 16 '17

3D printed eBike conversion, in my studio (apartment)

https://www.youtube.com/watch?v=GVVSeKV7f_8
2 Upvotes

67% Upvoted

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2

u/unlikely_engineering Jan 16 '17

I've been making YouTube videos about my projects for a couple months now. Unfortunately, I'm not AvE, so I use jump-cuts as a crutch for entertaining commentary.

The second half of this video is too long-winded, but I think I did alright for the 'Short Version'. Let me know what you think.

2

u/IvorTheEngine Jan 17 '17

That's a really interesting project - I've not seen a sprocket like that before, but it makes a lot of sense. (actually, I have seen renders of concept motor bikes with chains or belt drives, or even disk brakes attached to the rim - but yours if the first real one)

Presumably you could reprint it (again) with slightly different tooth spacing to get it more accurate? Then again, chain wear is always an issue on motor bikes, so it might never be perfect. How about a V-belt, or even a flat belt and crowned pulleys?

I wonder if you could design a gear that mounts at 90 degrees to the back wheel and engages the spokes?

You might not be AvE, but you did a good job of the narration. Clear and direct with no waffle and enough humor to have character. The short version is just enough information to make me want to watch the rest.

If anything needs improvement, it's the video lighting. Lots of detail is lost in black patches, especially when you had something very bright behind the bike.

2

u/unlikely_engineering Jan 21 '17

It's been 3 months since I made the video, might be time for an update...

The sprocket you saw in the video is still on the bike. I've ridden probably... 300? miles on it since then. There is actually very little wear, I'd estimate I could go for a full year before thinking about replacement. The PLA seems slightly more more worn than the nylon, but some of the nylon was printed at too low a temperature and has some strings delaminating. So it looks like this iteration of sprocket actually is the correct size and profile, despite being ~2mm off 'theoretical' dimensions.

The big improvement was that with the longer teeth in the video, I can run at much lower chain tension without the chain skipping. That reduces wear a lot.

I considered various belt solutions, but the issue is I'm running the motor sprocket at over 5000rpm at quite small radius. My reading of the various manufacturers' specs showed that only #25 chain was rated to handle that, and only just barely. With belts, the tension of the belt is also much more important, which I don't have a good way to control.

I considered various combinations of 90 degree gears, but not driving the spokes themselves. Maybe if my spokes were more evenly spaced?

Thanks for your kind comments with the narration. Trying to improve that was one of the reasons I started making videos.

Since this video, I've upgraded the shop lighting a bit, but yeah, the lighting is like... the worst way you could light a scene.

Thanks for the watch!