E-bike motors explained: hub or mid-drive, torque, and the legal classes
Two decisions settle most of what an e-bike feels like: where the motor sits, and how it decides to help you. Everything else on the spec sheet is downstream of those.
Where the motor sits
There are two places to put a motor on a bicycle. In a wheel hub, where it drives the wheel directly. Or at the bottom bracket between the cranks, where it drives the chain and therefore goes through your gears. That single choice sets the weight distribution, the traction, the drivetrain wear and most of the price.
Of the eight e-bikes in this catalogue, seven are mid-drive and one — the Aventon Level.2 at €1,899 — is a rear hub motor. That ratio is not an accident: mid-drive has taken over the European market above about €2,500, and hub motors hold the entry end where the cost difference is decisive.
What placement does to the ride
| Rear hub | Mid-drive | |
|---|---|---|
| Weight | Out at the back wheel. The bike feels tail-heavy and lifting it is awkward. | Low and central. Handles closest to a normal bike. |
| Traction | Pushes the bike. Can spin on loose or wet climbs. | Drives through the wheel as your legs do. Better on gravel and trail. |
| Hills | Fixed gearing — bogs down and heats up on long steep climbs. | Change down and the motor stays in its efficient range. |
| Drivetrain wear | Chain sees only your legs. Chains and cassettes last. | Chain sees your legs plus the motor. Expect faster wear. |
Neither column is the winner. A hub motor on a flat commute is quiet, cheap, mechanically simple and leaves your chain alone — a genuinely sensible bike, not a compromise. A mid-drive is the right answer as soon as there are real hills, a real load, or loose surfaces, which is most of why people buy an e-bike in the first place.
The weight is worth stating plainly. The e-bikes here weigh 22.8 to 27.3 kg against 8.1 to 15.6 kg for everything else. That is a bike you do not carry up stairs, and it is the first thing to check against the storage question in how to choose a bike .
Torque, not watts
In the EU the power figure is fixed by law at 250 W of rated continuous output, so every legal pedelec quotes the same number and it tells you nothing. Torque, in newton metres, is the figure that varies and the figure you feel. It is the twisting force at the cranks, and it is what decides whether the bike pulls away from a junction on a slope or asks you to do the work.
| Motor torque | Suits | Notes |
|---|---|---|
| About 40–50 Nm | Flat commuting, city riding, an unloaded rider. | Feels like a helpful tailwind. Quieter and lighter. |
| About 50–65 Nm | Rolling terrain, a commute with one real hill, light luggage. | The general-purpose choice for most riders. |
| About 65–85 Nm | Steep hills, trail riding, a heavy rider or frequent loads. | Obvious shove from a standstill. Harder on the chain. |
| 85 Nm and up | Cargo bikes, child seats, mountains with luggage. | Overkill for flat commuting, and you pay for it in battery. |
Read those bands as guidance, not thresholds: a 50 Nm motor will still climb, it just asks more of your legs. And torque costs range — more assistance drawn per kilometre means a bigger battery for the same distance, which is the subject of e-bike range explained .
The catalogue, from the entry hub-drive to the full-suspension mid-drives:
The sensor is what you actually feel
This is the most under-reported spec on an e-bike, and the one riders notice within thirty seconds of a test ride. The motor has to decide how much to help. There are two ways it can decide, and they produce completely different bikes.
Cadence sensor
Detects only that the pedals are turning, then applies whatever the chosen assist level says. Cheap and reliable. The feel is switch-like: turn the pedals and the bike surges, stop and it fades a moment later. It can lurch when you set off, and it gives you no reason to pedal harder, because pedalling harder changes nothing.
Torque sensor
Measures how hard you are actually pushing and multiplies it. Push harder, get more. The result feels like your own legs with the volume turned up rather than like a throttle, it is smoother in traffic, and it typically uses less battery for the same journey because it only helps in proportion to your effort.
Mid-drive systems from the established motor makers are torque-sensing as a rule. Hub systems vary, and at the entry end cadence sensing is common. If a listing does not say which it has, assume cadence and ask.
What the legal classes mean
In the EU, a bike that keeps its bicycle status is a pedelec under EN 15194: motor rated at no more than 250 W of continuous output, assistance only while you are pedalling, and assistance cutting out at 25 km/h. You can go faster than that under your own legs; the motor simply stops adding. A walk-assist mode of up to 6 km/h is also permitted.
A pedelec is legally a bicycle. No registration, no licence, no insurance plate, and access to cycle paths. Every e-bike in this catalogue is built to that standard, which is why they all quote 250 W.
An S-pedelec assists to 45 km/h and is a different legal animal: in most of the EU it is classed as a light moped, which brings registration, an insurance plate, a licence category and a specified helmet. The details — which helmet, what minimum age, whether cycle paths are open to you — vary by country and change. Check locally before you buy, not after.
Service, parts and the lock-in risk
An e-bike is a bicycle plus a proprietary electrical system, and the second half is where the long-term risk sits. Motors, batteries, displays and controllers are almost never cross-compatible between brands, diagnostics usually need the manufacturer's software, and firmware updates come through a dealer.
- Check the motor is from a maker with a dealer network you can reach. A motor fault on an obscure system can leave a €3,000 bike immobile for months.
- Ask what a replacement battery costs today, and whether the model is still supported. It is the single most expensive part and it does wear out.
- Expect faster chain and cassette wear on a mid-drive. Budget for chains on the schedule in maintenance basics , not when they skip.
- Brake pads and rotors work harder on a 25 kg bike. Inspect them more often than you would on an unassisted bike; replace pads at the minimum thickness the pad maker marks, and use a mechanic if you are not certain.
None of this argues against buying one. It argues for buying a mainstream system from a shop you can get back to. If you are still deciding whether an e-bike is the right bike at all, the finder weighs the assisted and unassisted bikes against the same route.
Questions readers ask
- Is a hub motor a bad buy?
- No. On flat ground, with a torque sensor or a well-tuned controller, it is quiet, simple and much cheaper, and it leaves your chain alone. It becomes the wrong choice when there are steep or repeated climbs, loose surfaces, or heavy loads, because it cannot change gear to stay efficient.
- How much torque do I need for hills?
- For regular steep climbing, look at roughly 65 Nm and upwards, and more again if you carry a load or a child. Below that the bike still climbs, it just asks more of your legs. Torque matters more than the power figure, which EU law fixes at 250 W on every legal pedelec anyway.
- Do I need insurance or a licence for an e-bike?
- Not for a standard 250 W, 25 km/h pedelec in the EU — it is legally a bicycle. An S-pedelec assisting to 45 km/h is treated as a moped in most countries, which means registration, an insurance plate, a licence and a specified helmet. The details vary by country, so check locally.
- Can I ride an e-bike with a flat battery?
- Yes, on any of the systems here. It rides like a heavy bicycle — 22.8 to 27.3 kg for the ones in this catalogue — and a mid-drive adds a little drag through the motor. It is fine for the last few kilometres home, and not something to plan a ride around.
- Does the motor wear out the chain faster?
- On a mid-drive, yes, because the chain carries your effort plus the motor's. Many riders replace chains roughly twice as often as on an unassisted bike. A hub motor drives the wheel directly and leaves the drivetrain seeing only your legs.