Making an electric monotrack bike.

Monotrack bike driven by an electric motor. Uses three go-kart rear wheels to guide the track which avoids lathe work making rollers from old gas cylinders etc. The build was achieved with regular tools, box section steel mainly and a budget MIG welder. I used some 90 degree pre-bent tubes for the seat mount.

Shown here being ridden by Nick Thatcher, a fellow builder of strange electric projects:

By keeping weight of the rider over the driven inner rearmost wheel, this grips the track OK without having to use any kind of interlocking sprocket drive with the track.
Track is cut down from a large car tyre/tire. The is shown near end of the video. Small tracks from diggers and snowmobiles for example are quite expensive so for a fun project a cut-down car tyre (not my original idea) works really well at around US$45 part-worn. I found tin snips to be much better than the oscillating multi-tool I assumed would do the job.

Why electric?
You tend to get a lot less hassle testing in public places if your machine does not have a noisy 2-stroke engine and is practically silent in operation. You can claim moral high ground by stating with a completely straight face that this is the future i.e. an EV, whereupon most people relax, become curious and ask more about it.
I had most of the parts already from the Electric Beach Luge:

Why call it the Vector?
Because it likes to go in straight lines (think vector graphics). I have some ideas for steering mechanism experiments. One would be to make it self balance on a smaller contact point such as the middle or rear wheel when you press a button, then steer it by leaning as you would do with a unicycle. People are asking me how you steer it, you don't! You stop and adjust your direction, maybe I should have a compass mounted on the front.

Inspired by:

The 1939 Lehaitre tracked motorcycle

Lyn Gentry

Motor: 24V 500Watt from golf cart.

Not cheap but protects itself against failure, short circuits etc so lives to fight another day if you make a mistake. At present it has been set up in the simplest potentiometer control mode (see datasheet).

Twistgrip potentiometer: Magura Twist Grip Throttle 0-5K Ohm

Battery: Chinese e-bike 24V 10Ah battery pack.

Go-kart parts: Rear wheels and tyres x 3. One axle tube, I used 30mm diameter, cut into 3 lengths. 30mm bearings and shells x 6. Largest sprocket that will fit the tyre size + a sprocket carrier. Suitable chain and 11 tooth motor drive sprocket i.e. smallest obtainable, giving maximum torque at the wheel. All bought used from web.

Other: Mountain bike handlebar and centre clamp system - lowest cost ones I could find on ebay. Main power switch is emergency battery cutoff type as used in racing cars, the sort with the large red key that you twist. This key can be removed which stops small children accidentally starting it up. KISS approach i.e. Keep It Simple - Stupid !

Track tensioning system is described in the video, similar to a motorbike, moves rear wheel further backwards by turning a bolt on each side.

Chain tensioning system is same concept as used on car alternators, i.e. motor hinges forwards and then clamped in position.

Future mods:
Speed and power are about right but battery does not last that long as the track is quite energy-sapping as would be expected. Larger battery capacity would be good. Steering system needs work. May add in some self-balancing properties.

[mad.engineer]

Only just found this.
well done John, didnt know you had done it, will give you a race next time we are over
.regards Lun

[Shakingstevesallotment]

Brilliant build, now make it faster 👏 👌 👍 😀

[TGiFoosday]

Pretty cool use of some Obtainium I'd say.👍

[um]

Nice invention
Science Ficción become to reality
😂😂😂😂😂😂
That's the way
Good Job

[klausstock]

Yep, got the Vector pun and liked it! Straightforward!

[ManMan]

Muy lindo tu proyecto amigo, felicidades, explicanos y enséñanos como fue que vinculaste el plato a la al eje trasero ..

[damos_cars]

Good to see you had protective gear on! :-)

[yharmacy]

well done John, you are a terror with your inventions, keep it up and give me inspiration

[mastermati]

I'd love to see it a little bit faster! Hope you'll get needed resources!

[Baer]

When I have my shop I'm going to make one from a truck tyre so it can safely make speed and brake

[matthewallen]

I thought the same thing, just use go cart wheels, I miss my shed more then my wife.

[KevinsWow]

I wonder if you built 2 of these and put them on a motorcycle frame. Build your own replica of Deathwheel from wow. Great job and video BTW.

[reikhard]

Lol, amazing! It would look even better if it was longer...

[Lofi-.-beats]

but wait, can it turn? in the video it only shows the Monotrack bike going straight. the only implied turn was at 5:23, where John changes his Center of mass to the left, making the vecter turn left.

[TheMaidenOnes]

omg, awesome! wish you had some offroad (non flat gound) video, what incline can you climb? I guess the motors are the limiting factor?

[jimcooper]

Great project!
Could you provide some dimensions of the frame?

[greenwave]

Electric Unicycles are already a thing for a reason lol

[benjamind]

Cool! What power is the motor? Is steering done by weight shift?

[createinvent]

That is pretty rad, thumbs up! Is the adjustment piece shown around 2:18 on both sides, or just the side shown? Guessing that grips the axle and pulls it tight?

[leif]

Very nice. Would be great to go at speed.