SDKEBOOST

Rather than asking riders to buy a new e-bike, SDKEBOOST aims to retrofit the one they already ride. The Kickstarter project comes from a team of engineers, cycling enthusiasts and former smart-mobility designers, and the system is built from three components: motor, battery and controller. According to the maker, it fits without specialist knowledge and integrates without spoiling the bike's original design.

Motor and battery

At its core is a 700W high-speed brushless motor, with continuous output tuned to local regulations: 20 mph (Class 2) in the US, and 25 km/h in Europe, the UK and Australia. Power comes from a removable 13.5Ah lithium battery using 18650 ternary lithium cells, which the maker rates for up to 80 km (about 50 miles) in assist mode. The battery can be carried indoors for charging and doubles as a power bank for phones and other devices, with smart protection against overcharging.

Riding modes and display

• Assist mode: the motor adds power in proportion to pedalling effort
• Cruise mode: hold a button to ride at a fixed 10, 15 or 25 km/h; releasing it stops the motor
• Standby mode: motor off, ridden as a regular bicycle

A waterproof smart display with adjustable brightness shows real-time speed, battery level, ride time and distance.

Friction drive, refined

Fixed contact pressure between a friction roller and tyre is a common source of slip, noise and uneven wear in clip-on kits. SDKEBOOST's Adaptive Pressure Control (APC™) uses a built-in pressure sensor to adjust contact force in real time according to road conditions and speed, increasing it on wet surfaces and easing off on smooth asphalt. The maker quotes an operating noise of 58dB, describes the design as all-weather with waterproofed motor and battery internals, and includes an integrated fender to shield the drivetrain and components from mud and spray.

The maker lists compatibility with city, mountain, road, gravel, folding and trekking bikes, but the system requires a rear triangle frame. Full-suspension mountain bikes, some folding bikes and bikes with certain rear racks may not be supported, and the maker recommends checking its compatibility guide.