Simple Electric Bike Conversion from 3D-Printed Parts

Challenge: Perform an electric conversion on a bicycle. Problem: No significant metal working skills or equipment. Solution: 3D print everything needed to electrify the bike.

At least that’s the approach that [Tom Stanton] took to his electric bike build. Having caught the electric locomotion bug on a recent longboard build, [Tom] undertook the upgrade of a cheap “fixie,” or fixed-gear bike. His delta printer was big enough for the motor mount and weather-resistant ESC enclosure, but he needed to print the drive pulley in four quadrants that were later glued together. We can’t say we hold much faith in the zip ties that transmit all the torque through the rear wheel’s spokes, but as a proof of concept it seems sturdy enough. With a throttle from an electric scooter and a battery in a saddle bag, the bike turns in pretty decent performance — at least after a minor gearing change. And everything blends in or accents the black frame of the bike, so it’s a good-looking build to boot.

Want to catch the cheap electric personal transportation bug too? Check out this electric longboard, or this all-terrain hoverboard.

Thanks for the tip, [Brett Collis].

24 thoughts on “Simple Electric Bike Conversion from 3D-Printed Parts

  1. yeah… i dont see how this is going to work for longthat thing is gonna wear out in no time, and the duration the batteries will work is probably nothing in a usefull range either, but never the lkess its a good project, now we need to be able to print that in metal, for low prices/affordable personal printers.

  2. i always figured if i did this mod id get me the rear rim of a single speed bike, widen the front fork using the wood blocks wedge and hammer method. stick a sprocketed rim in there. then i could just use an off the shelf sprocket and chain drive. id just have to print the motor mount and sprocket adapter. this would allow the front rim to free wheel when not powered, reducing friction when pedaling. then an r/c hobby type controller would be enough. then throw in a microcontroller for battery monitoring and throttle control.

  3. Would you also run the motor in reverse to brake thus breaking the motor? That’s how a fixed bike works. Silly. Naked motor…grit…
    The front wheel trick sounds good except going up hills when you need it most.

    1. Using the motor to brake won’t work. The motor mount will twist around the tube it’s attached to. The mount, the belt and more will be destroyed.

      Wren of Corridor Digital did this build on the Sam&Niko channel. He forgot to disable braking on the ESC with exactly that happening.

    2. Fixed gear bikes are slowed down by applying a counter force to the pedals whist the are still going forward, like retro thrust in space. Energy spent to slow down. Whereas squeezing a brake will suck out energy with little effort.
      My statement was to use both spellings and their respective meanings, questioning the electrical equivalent of the thrust of a rocket by applying REVERSE power to the motor whilst going forward to slow down, which would certainly destroy the motor. This is the opposite of regenerative braking.

      Not having 2 good brakes (able to lock up and skid when riding) on a bike is not safe yet legal, much more so on an electric bike. Not to mention pedals that are always moving, I couldn’t handle (foolal?) .

      1. In a rocket, due to the lack of something to push against, it costs energy to slow down.
        Classical brakes just dissipate the kinetic energy into heat. Easy, cheap.

        Once you have an electric motor you can command the motor to provide a negative (against the direction of travel) torque. This results in the conversion of kinetic energy into electric energy. You charge your battery. Regenerative braking. It really works! (except on my bike, as my motor has freewheeling: It can push the wheel, but (when going forward) the wheel cannot push the motor).

  4. You can get fixie hubs with threads for gears on both sides. With a tensioner, you can reverse the wheel and have two different gear ratios to choose from. From the perspective of this bike, you could use the second gear thread to hold the gear for the electric motor. That would eliminate the need for the zip-ties. I suppose a hub for disk brakes would be similar – attach the gear to the brake disk mount.

    1. The disc hub was my first thought, too. 6 bolts, easy mounting and designed for the workload. Would probably use a machined steel gear mounted on the disc hub. Frames set up for both brakes exist, so you could have front disc, rear calipers. Front is more important anyway!

  5. Good example of prototyping, they proved it was worth taking further. I wonder if a super capacitor and a smarter controller would let you get back some of your charge on the down slopes?

  6. I think that motor sticking out so much is a bit of a flaw, I think it might have been better to have it mounted over the wheel the other way round and just have a longer drive belt, with some guides/containers to keep it in line.

  7. As he mentioned he is a student, I was hoping it was going to be a low-budget thing…
    £160 bike
    £70 motor
    £110 ESC
    £9 throttle
    £15 battery (guess)
    makes £364 plus printed parts, cheap by eBike standards, but a project that needs some investment. Hopefully he will make enough off his vids to offset that, but having (recently) been a student, that is a great deal of money.

    Cracking build though, hopefully the big pulley will last out, it should last long enough to work out how to make a better replacement.

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