Hub Motor or Mid-Drive: Which Conversion Fits the Bike?

A conversion kit has to match the bicycle that is already in the workshop. The two layouts we supply do that job differently.

Hub motor: change the wheel

A hub kit replaces the front or rear wheel. The motor, spokes and rim arrive as one wheel, built to the size you specify. Installation is a wheel swap plus the controller, display and pedal-assist sensor. The existing gears, chain and bottom bracket stay as they are.

That is the simpler build for city bikes, folders and fleets that all use a similar wheel. You do need the dropout width. Our geared and direct-drive kits cover about 100–142 mm. A front hub leaves the drivetrain alone. A rear hub has to match a threaded freewheel or, on a modern frame, a cassette and a wider axle.

Geared hubs freewheel when the power is off, so there is little drag while pedaling. Direct-drive hubs have no internal gears to wear and stay quiet, which suits sustained speed more than stop-start hills. See the 500W direct-drive kit and the hub motor series.

Mid-drive: use the bike’s gears

A mid-drive bolts into the bottom bracket and turns the chainring you already have. Climbing uses the bicycle’s own ratios, so a smaller motor can feel stronger on hills than a hub of the same wattage. The trade-off is the shell: the bracket width, threading and chainline have to fit. Our Tongsheng kits are built for a standard threaded bottom bracket and do not need a frame modification.

The TSDZ8 750W is the compact one. The TSDZ16 1000W is the heavier climber, with the controller inside the motor housing.

What to tell us

For a hub: wheel size, front or rear, dropout width, brake type, and freewheel or cassette. For a mid-drive: bottom-bracket width, chainline if you know it, and whether the route is flat commuting or loaded hills. Send that with the quote form and the target quantity. We confirm the model before you order.