Hub motor vs mid-drive: which e-bike motor is better
Almost every e-bike motor is one of two designs, and the difference between them decides how the bike feels more than the wattage does. A 250W mid-drive and a 250W hub motor are not variations of the same thing. They are different machines.
This guide explains what each one does, where it fails, and which suits the riding you actually do.
Where the motor sits
A hub motor is built into the centre of a wheel, usually the rear. It drives the wheel directly, independently of your pedals and gears.
A mid-drive motor sits at the bottom bracket, where the cranks are. It drives the chainring, so power goes through your bike's gears and chain before reaching the wheel.
That single difference in position explains everything else.
Hub motors: simple, cheap, effective
The hub motor is the older and simpler design. It has no connection to the drivetrain, so there is nothing to align, and no extra wear on your chain and cassette.
What it does well:
- Cheap to make and to buy. This is why almost every e-bike under about £700 has one.
- Reliable. Few moving parts, no gears inside the motor in the simplest versions, and nothing to service.
- Independent of your gears. If you are in the wrong gear, the motor still pushes you. That makes it forgiving for riders who do not want to think about shifting.
- Works when the chain fails. A snapped chain stops a mid-drive dead. A hub motor will still get you home, on throttle or on assist, as long as the battery holds.
Where it falls short:
- It cannot use your gears. On a steep hill, a hub motor pushes with the same force regardless of what gear you are in. A mid-drive can drop to a low gear and multiply its torque through the drivetrain; a hub cannot. On long climbs with a heavy rider, this is the difference between comfortable and strained.
- Weight in the wheel. A hub motor adds 3-5 kg to the wheel it sits in, which affects handling and makes the wheel harder to remove for a puncture.
- Rear-wheel removal. Fixing a rear puncture on a hub-drive bike means disconnecting a motor cable and dealing with torque arms or nuts, not just a quick-release.
- Regulation limits. Because it drives the wheel directly, a hub motor can be built to push beyond the legal assist limit more easily, which is why so many high-power imports use them. In the UK, that makes them a legal problem, not a technical one.
Mid-drive motors: the better ride, at a price
The mid-drive is the design used by almost every premium e-bike, and for good reason.
What it does well:
- It uses your gears. Drop into the lowest gear and the motor's torque is multiplied by the drivetrain. This is why a 250W mid-drive climbs better than a 500W hub motor in practice.
- Balanced weight. The motor sits low and central, which is the best place for handling. The bike feels like a bike.
- Efficient. Because it works at the cadence you pedal at, it uses less energy for the same assistance, which means more range from the same battery.
- Normal wheels. Front and rear wheels are standard, so punctures and wheel changes are ordinary jobs.
Where it falls short:
- Cost. A mid-drive system typically adds £400-1,000 to a bike compared with a hub of similar power.
- Drivetrain wear. All that torque goes through your chain, cassette and chainrings. Chains wear faster, and on high-torque systems, chainrings wear noticeably. Budget for shorter service intervals.
- It needs you to shift. Ride in too high a gear up a hill and the motor labours. The bike rewards good technique and punishes laziness.
- Chain failure stops you. A broken chain leaves you with a very heavy push-bike.
The comparison, by use
| Situation | Hub | Mid-drive |
|---|---|---|
| Flat town commuting | Fine | Fine, nicer |
| Short trips, low mileage | Good value | Overkill |
| Steep or long hills | Struggles | Clearly better |
| Heavy rider or loaded bike | Strains | Better |
| Off-road, technical climbs | Poor | Clearly better |
| Budget under £700 | The only real option | Not available |
| Minimal maintenance | Simpler | More drivetrain wear |
| Rear puncture repair | Awkward | Normal |
The number that matters is not the wattage
A common mistake is to compare motors by their rated watts. It is the wrong comparison, because the rating is a legal limit, not a measure of performance.
In the UK, a road-legal e-bike must have a motor rated at 250W continuous. Both designs are usually sold at that rating, and both are capped at 15.5 mph of assistance. On paper they are identical. In practice the mid-drive will feel considerably stronger on a hill, because it is multiplying its output through a low gear.
What actually differs is torque and how it is delivered. See our guide to torque and power in e-bike motors for what Nm and W actually mean and why the two are not interchangeable.
Which one to buy
Buy a hub motor if: you ride on roads and mild paths, your budget is under about £800, your terrain is flat to gently rolling, and you want the simplest thing that works. This describes most commuters, and there is nothing wrong with it.
Buy a mid-drive if: you have real hills, you carry loads or a child seat, you ride off-road, or you want the bike to feel like a bicycle rather than a moped. You will pay more and you will replace chains more often. It is worth it.
Do not buy either above 250W if you need it for a UK road. Above that rating the machine is a motor vehicle, not an e-bike, and it needs type approval, registration, tax, insurance and the correct licence. Our guide to UK e-bike law sets out exactly where that line falls, and our legality checker will tell you in one step whether a specific bike you are looking at qualifies.
A note on the bikes we list
Most of the e-bikes in our catalogue are hub-drive, because most of the market at our price points is hub-drive. Where a listing states a mid-drive motor, the product page says so. Where the listing does not say, we do not guess: the motor position is not always stated by the seller, and inventing it would be worse than leaving it out.
If you are comparing two models and the difference comes down to motor position, look at the photographs: a mid-drive motor is a large housing at the bottom bracket, between the pedals. A hub motor is a fat cylinder in the centre of a wheel. It takes one second to tell them apart once you know what you are looking for.