Electric bikes have increased ... 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 ...

[joejoeboom’s] 5-minute electric ... bicycle’s frame. He positioned the drill so the chuck pressed firmly against the side of the bicycle’s rear wheel, creating a simple friction drive ...

I'm usually test-driving electric cars, but lately I've been playing with a fun alternative: a clip-on electric motor that converts an ordinary bicycle ... a simple friction drive system, it's ...