Electric bikes have increased in popularity dramatically over the past few years, and while you can easily buy one from a reputable bicycle manufacturer, most of us around here might be inclined to at least buy a kit and strap it to a bike we already have. There aren’t kits available for every bike geometry, though, so if you want an electric BMX bike you might want to try out something custom like [Shea Nyquist] did with his latest build. (Video, embedded below.)
BMX frames have a smaller front triangle than most bikes, so his build needed to be extremely compact. To that end, it uses two small-sized motors connected together with a belt, which together power a friction drive which clamps against the rear tire to spin it directly. This keeps the weight distribution of the bike more balanced as well when compared to a hub drive, where the motor is installed in the rear wheel. It also uses a more compact lithium polymer battery pack instead of the typical 18650 lithium ion packs most e-bikes use, and although it only has a range of around three miles it’s more than enough charge to propel it around a skate park.
The build boasts impressive numbers too, at 2.5 kW peak power per motor. This puts it in electric motorcycle territory, and it’s indeed fast despite its small stature. For a true high speed e-bike experience, though, you’ll need a slightly larger frame and motor even if it means tossing safety out of the window.
All fun until the Li-Po goes pop in between your legs!
Good one!
It sounds better if you sing it as “Pop goes the Li-Po…”
Anyone remember the old time bike motor kit from the 70’s? It was basically a chicken power gas engine that sat on a movable platform located over the rear wheel. The engine had a roller that would interface to the bike wheel. To get going, all you needed to do was use a lever to lower the platform onto the wheel. Very basic, but got the job done…
Velosolex? That was on the front wheel.
Yes the most iconic one, but still before, there were also some with movable mechanism on the rear wheel.
B.A.E Powerplus?
Amazing, that company is still in business.
https://solex.world/en/news/
And France offers subsidies to repair/buy electric versions.
Found it. It was the Trojan Minimotor.
http://www.users.globalnet.co.uk/~pattle/nacc/arc0119.htm
It was made from 1955 onwards