Spiny 2 is a Kickstarter-funded e-bike conversion kit that uses a friction drive to turn an ordinary bicycle into an electric-assist bike in about three seconds. The motor and battery are housed in a single 2.2 kg unit that clicks onto mounting hardware installed on the bike. Cadence and speed sensors trigger the roller to press against the rear tire when the rider pedals, providing assistance in roughly a quarter second, and lifting away when pedaling stops to avoid drag.
The US version is rated at 250W nominal with 750W peak and assists up to 20 mph; Canadian models peak at 500W, and most other markets are limited to 250W and 25 km/h. A 266Wh battery is built into the removable unit, with a claimed range of up to 90 km, though the Electrek review cautions that real-world range will be far lower for typical riders. The kit charges via USB-C PD and carries an IP65 weather-resistance rating. It fits many road, city, hybrid, and touring bikes, but not rear-suspension models, and it can't accommodate a normal rear fender.
The reviewer notes that this is a crowdfunding project and has not been personally tested, though the company has delivered hundreds of units of its previous version. Deliveries are estimated for April 2027, which the source stresses is not a guarantee. If it works as promised, the Spiny 2 could offer a convenient way to add electric assistance to an existing bike without permanently converting it.