Electrifying my track bike


10 mW
May 15, 2011
London UK
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I know that an aluminium track frame is not the most suitable frame to turn into an ebike. I do have some other bikes, which are also all track frames 😂
I have youtube channel https://www.youtube.com/@jetthepanda where I film my people riding around the city. Some of these people are abnormally fast freaks of nature, some are even pro's and even though I am actively training to get myself faster, I doubt I will ever be able to keep up with them when they are really pushing. So I've started looking into the idea of turning one of my bikes into an ebike. I am happy to do most of the work pedalling myself. I just need a little extra boost to help me sustain the higher speeds, which I think electricity would be perfect for. The speeds I'm having problems getting up to quickly and staying at are around 30mph and up, I can get there but not as quickly as the guys I'm following and I can't maintain it long enough to stay on the guys I'm filming.

I want to keep the bike looking as stealthy non ebike as possible. I was originally thinking rear hub with a bottle battery. I found these hubs with controller and torque sensor built into the hub, all you need to do is plug a water bottle battery in.
I contacted both of them and they do not provide their hubs for 120mm drop out spacing. I wouldn't be adverse to grinding the axle down myself. I build all my own bikes and wheels, I think I'm pretty handy when it comes to this kind of stuff.

Does anyone know of a similar rear hub that would fit into 120mm dropouts? Or do you know if it's hard to modify one of the above hubs to fit?

I then came across these friction drives, which I think are very interesting. I wouldn't need to modify anything, all I'd need to do is bolt the motor on. I could even take it off when I didn't need it.

I am considering the Aliexpress friction drive because that, plus a water bottle battery enclosure, some batteries and a BMS seems to be the most economical route. I think it would be more powerful than the cheapest qiroll kit too QR-E MUTE +B60 Battery Kit I think the motor of the qiroll looks nice, but the battery and throttle button look terribly designed. I would much rather have a stealthy water bottle that actually looked like a water bottle.

What are your thoughts? Does anyone have experience with the Aliexpress friction motor? What BMS do you recommend for a small DIY water bottle battery? Will I be "spinning out" with these lower powered motors at the speeds that I want to go at or will they still be helping me along?

I do have a fork that can take a disc brake and I would use that fork with a disc brake if I went electric. I Would also mount a rear brake and change the fixed cog to a freewheel.
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By stealthy do you only mean visually? There are many options, but only a few if you don’t want it to be noisy. A small geared hub would be visually stealthy, but won’t be silent. Why do you care?
By stealthy do you only mean visually? There are many options, but only a few if you don’t want it to be noisy. A small geared hub would be visually stealthy, but won’t be silent. Why do you care?
Visually. I just want it to look like a normal bike for my own aesthetic preference.
I thought this was a compelling approach:
My RC Mid Drive with Single Stage Reduction
Thanks for that, I'm just taking a look through their thread now 👀

Still quite interested in those friction drives I listed above!
Brainstorming here, absent much knowledge about whether this is possible or not.

Use a small silver fast wind geared front hub (100mm O.L.D.), but mount it on the rear.
Since those bikes don't use rear brakes, utilize the hub's disc brake mounting screws to add a sprocket to the left side:

Flip the bottom bracket to run the chainring on the left side.*
Add a freewheel to to mount the chainring on**
Use a Grin phaseruner for the controller because it's tiny, and for easy connection if you get a Grin hub motor. VESC would be another option.
Bottle cage battery is an option, but if you carry a camera bag/backpack, you could stash the battery there, mount the phaserunner on the seatpost or maybe under the seat, for a short run to the backpack.

* Have to think this through, due to the threads, etc. There are other bb options that may be easier to reverse. Had a beer to kick off the brainstorming, so too much detail for this stage, LOL.

** This may need to be fabricated. There are some freewheel cranksets out there.

Thoughts - Small silver hub might be mistaken for a Nexus, etc. so may not attract too much attention. Chain line may be a challenge. You didn't mention your budget. Those RC motors can be obnoxiously whiny, but I saw one a couple of months ago that wasn't so bad.
Looks like you don't need electric bike to be fast, you just need to ignore all the traffic rules
For me, Aliexpress is a no no, but your experience may be different. You might consider the small rear motors employed by Bianchi and other European makers. Or, there is an individual who posts here (Kepler AIR) and seems to have perfected friction drive.
I think yours is a great candidate for a simple minimal front hub conversion with battery and controller in a handlebar bag or on a front rack. One of the Bafang dual stage geared hubs would be good for that. Use a sine wave controller if you want it to be very quiet.

I strongly suggest using a coaster brake rear wheel or at least a freewheel. Fixed gear on the street is always a super sketchy prospect, but most especially when the motor can drag you along. There are some nice looking aluminum shell coaster brakes from KT and Wheelmaster these days. No need to add a lever or cable to use one of those. Also it enlists your "pedal backwards to stop" fixed gear instincts.
It may be easier to find a different bike with a 7-speed rear free wheel. They're inexpensive and buy a small geared motor for the rear or the front see if you can find a complete kit that doesn't look too out of place for you. It won't be invisible.