Conversion Kits
Used electric bike conversion kits give a standard bike an electric upgrade without the cost of a whole new setup. Cranxs connects you with sellers offering new and second-hand kits from brands like Bafang, Swytch and Tongsheng, suited to road, mountain and commuter bikes.
Front-hub, mid-drive or rear-hub?
A front-hub motor is the simplest to fit, since it replaces the front wheel and leaves the drivetrain alone, and Swytch built its reputation on that approach. A rear-hub system puts the drive where the weight and traction already are. A mid-drive from Bafang or Tongsheng mounts at the bottom bracket and drives through your gears, which is the better feel on hills but the more involved fit.
Will a kit fit my bike?
Compatibility is decided by the frame, not the kit. For a hub motor, the wheel size and the dropout width have to match; for a mid-drive, it is the bottom bracket shell that has to match. Also check the brake type and whether there is room for the battery on the down tube. A tidy commuter or an older mountain bike frame usually converts more easily than a modern road frame.
What comes in a kit?
A complete kit is the motor, a battery, a controller, a display and a pedal or torque sensor, plus the wiring between them. Used kits are often sold incomplete, so check the list item by item before buying, and confirm a matching charger is included, because sourcing one for an unbranded battery afterwards is harder than it sounds.
Is a converted bike road legal in the UK?
The same rules apply as to a factory e-bike: a motor rated at no more than 250W, assistance cutting out at 15.5mph, and a rider aged 14 or over. Kits sold with higher output or with the limiter removed take the bike out of that category and into moped territory, so check the rating and the settings on anything second-hand.
What should I check buying used?
Battery condition sets the value of the whole kit, so ask its age, cycle count and real-world range, and avoid any pack with swelling or impact damage. Check the wiring loom and connectors for corrosion and cut cables, since these are usually removed from a bike rather than unboxed. Ask whether it was working when taken off, and compare it against a complete build using the wider e-bike components range.