Mid-drive vs hub motor
A mid-drive motor sits at the bottom bracket and drives through your gears, so it can stay in its efficient range on any gradient. A hub motor drives the wheel directly, which makes it simpler and cheaper but leaves it working against a fixed ratio on every climb.
Mid-drive, for one reason above the others: weight sits low and centred, so a loaded bike handles like a bicycle rather than like a bicycle with a weight bolted to the back wheel.
| Criterion | Mid-drive motor | Rear hub motor |
|---|---|---|
| Climbing | Uses the gears; holds efficiency on any gradient | Fixed ratio; loses efficiency and heats up on steep climbs |
| Weight distribution | Low and centred, near the bottom bracket | High and rearward, at the axle |
| Drivetrain wear | Motor torque passes through belt or chain | Drivetrain sees only your legs |
| Rear wheel service | Standard wheel; puncture repair is normal | Motor cable and torque arms to disconnect first |
| Cost | €90–180 more in the BOM | Cheapest way to make a bike assisted |
| Noise | Audible gear whine under load | Near-silent |
| Regenerative braking | Not possible through a freewheel | Possible on direct-drive hubs, worth a few per cent |
The case for the hub motor is better than enthusiasts admit
On a flat commute, a rear hub motor is quieter, cheaper and mechanically simpler, and it does not put motor torque through a belt or chain. In Amsterdam or Milan, the mid-drive advantage is small enough that you are mostly paying for handling.
The argument changes with gradient. A hub motor on a 6% climb is stuck in one ratio while the motor slows, and a slow motor is an inefficient, hot motor. That is the point where a mid-drive that can drop two gears pulls decisively ahead.
What mid-drive costs you
Every newton metre the motor makes passes through the transmission, so a mid-drive wears belts, chains and sprockets faster than your legs alone would. This is why we pair ours with a carbon belt and an e-bike-rated internal hub instead of a derailleur: the components that would wear are the ones we removed.
It also makes the bottom bracket area dense and hard to service, and it is the reason the motor must be specified before the frame is drawn rather than after.