A detachable electric drive kit that converts an existing bicycle into an e-bike has been released. It can be mounted only when needed to use electric assist without changing wheels or the drivetrain.

On Sept. 30 local time, mobility outlet BikeRumor reported that Spiny EV Solutions SL unveiled its second-generation detachable e-bike kit, Spiny 2. After installing the initial mount and sensors, the main unit can be attached to or removed from a bicycle in about 3 seconds.

Spiny 2 focuses on not permanently converting an existing bicycle into an e-bike. It works by installing a dedicated bracket on the frame and inserting a main unit that combines the motor and battery.

Its drive method also differs from conventional e-bikes. Spiny 2 uses a friction-drive system in which a roller connected to the motor contacts the rear tyre directly to deliver power. The company explained that this removes the need to replace the rear wheel, hub or existing drivetrain.

Spiny co-founder Marco Coccirella (마르코 코키아렐라) stressed that people should not have to choose between an existing bicycle and electric assist. He explained that Spiny 2 aims to let riders use electric power only when needed without turning a bicycle into a permanent e-bike.

Weight was also designed with portability in mind. The main unit combining motor and battery weighs 2.2 kg. It can be detached and carried away when parked, reducing the burden of managing both the bicycle and the electric system together.

Output and top assisted speed vary by sales region. The U.S. model supports 250W rated output and up to 750W maximum, with a top assisted speed of 32 kph. The Canada model limits maximum output to 500W. In most other markets it is sold with 250W output and a top assisted speed of 25 kph.

Electric assist is handled by a speed sensor and a cadence sensor. When pedalling is detected, the motor engages the rear tyre and operates within about 0.25 seconds. Users can select assist levels from 1 to 5, and the motor disengages from the tyre when pedalling stops.

Battery capacity is 266Wh. Spiny said it provides an assisted range of up to 90 km under ideal test conditions. Actual range may vary depending on terrain, road conditions, rider weight and the selected assist level.

Charging uses USB Type-C PD. The company puts charging time at about 0 to 4 hours. Assist levels can be adjusted through a dedicated app or an optional Bluetooth remote, and the app also shows ride information such as remaining battery and speed.

Features for durability and drive stability were also applied. The product has an IP65 dust and water protection rating and uses replaceable dual-compound tyre friction pads. Spiny explained the design aims to keep contact between the drive roller and tyre consistent even when riding conditions change.

Compatibility is also a feature Spiny 2 highlights. It does not require specific hub, wheel or drivetrain standards, and can be used widely on road, city, hybrid and touring bicycles, it said. It supports both rim brakes and disc brakes.

Still, it cannot be installed on every bicycle. It needs sufficient mounting space between the frame and rear wheel, and it does not support bicycles with rear suspension. Bicycles fitted with a rear mudguard or fender may require some modification to the section where the motor contacts the tyre.

The company also prepared separate adapters for various bicycles. These include a sport adapter for bicycles with narrow frame spacing and an adapter for Brompton folding bicycles.

Spiny 2 was unveiled on the crowdfunding platform Kickstarter on the day. The basic package includes the motor-battery unit, two sensors for speed and cadence, a frame mount and positioner, and four frame adapters.

A Bluetooth remote, a kit for a second bicycle, a fast charger, an additional battery pack, an anti-theft lock and a mudguard are offered as separate accessories.

Spiny is taking early-bird pre-orders through the Kickstarter campaign and expects worldwide shipping in April 2027, about 5 months after the campaign ends. Shipping costs are set separately depending on the region.

Spiny 2 seeks to differentiate itself from existing e-bike conversion methods by keeping key bicycle components intact and adding electric capability only when needed. In particular, the ability to detach and store the lightweight unit suggests it targets users who want to alternate between a regular bicycle and an e-bike depending on the situation.