Mid-Drive vs Rear Hub eBike Motors

01

How the two motor types compare

Where the motor sits, and what that changes.

A mid-drive motor is mounted between the cranks and turns the chainring, so its power travels through the chain and the bike’s gears, the same path your legs use. A rear hub motor is built into the back wheel and turns the wheel directly, so the chain and gears only carry your effort. Both can run a normal derailleur and cassette. Think of a mid-drive like a car engine driving through a gearbox, and a rear hub like a motor fitted straight to the wheel.

Mid-drive

Pros. High torque, 85Nm or more on performance models. Uses the bike's gears, so it can drop to a low ratio for steep climbs. Weight sits low and central.

Cons. Motor power runs through the chain, cassette and chainring, so they wear faster and can result in poor shifting performance under load or a very quickly worn out small cog on the cassette. Usually costs more than a rear drive.

Rear hub

Pros. The motor sits apart from the drivetrain, so the chain and gears only carry your effort and last longer. Simpler and lighter, with a sealed motor inside the wheel.

Cons. Adds weight at the back wheel. Has traditionally felt less natural to pedal. Lower torque.

02

Mid-drives and e-mountain biking

Why eMTBs are best with mid-drives.

Steep, loose climbs need a lot of torque at low speed, and a mid-drive is built for that. Because it drives through the gears, it can shift into a low ratio for a steep pinch and keep spinning at the speed it works best, multiplying its torque on the way to the rear wheel. Performance mid-drives like the Bosch Performance Line CX are rated at 85Nm and up, well above what a commuting motor needs.

An e-mountain bike with a Bosch mid-drive motor at the cranks — Image: Bosch eBike Systems

Weight placement matters off-road too. A mid-drive keeps its mass low and between the wheels, which keeps the bike balanced on technical ground and leaves the rear wheel light enough to follow the terrain.

The cost is the drivetrain. Pushing motor torque through a chain and cassette wears them faster, so trail riders replace them more often. On a steep trail that’s usually a trade worth making, because the climbing performance is the point. Also on these steep terrain rides, an ebiker will often still use all the gears, so the entire cassette wears more evenly. However, on flatter terrain, riders are often solely in the high gears, leading to rapid cassette wear, leading to frequent, costly replacements.

03

Rear hubs and commuting

What a rear hub does well on the way to work.

On a daily ride, a rear hub’s strengths line up with what matters most: fewer things to look after and fewer things to wear out. The motor drives the wheel rather than the chain, so the chain or belt and the gears only wear according to your pedaling effort. Compared to mountain biking, commuting average speeds are higher, which means a hub motor can run at an efficient speed, where they would otherwise potentially struggle on a loose mountain climb.

Lighter.

A commuting hub motor doesn't need a trail motor's torque, so the unit can be lighter.

Simpler.

The motor sits in the wheel, apart from the drivetrain, with fewer moving parts between motor and road.

More reliable.

It's sealed inside the hub, away from the grit and water that collect around the cranks.

Easier on the drivetrain.

Less load on the chain, cassette and chainring means less wear, which adds up quickly when you ride most weekdays.

Stop-start traffic, bike paths and rolling suburban routes are where this pays off.

Worth knowing

A rear hub puts extra weight at the back wheel, and depending on how it’s set up, can make removing the rear wheel to fix a puncture a little more involved than on a bike without one. If this is a concern, check how the rear wheel comes off on any bike you’re considering before you buy.

04

The new Ananda R900 and pedal feel

Taking the unnatural feel out of a rear hub.

The rear hub’s biggest weakness has been how it feels to pedal. Many hub based bikes feel more like being pushed than riding with stronger legs.

The Ananda R900 is a rear hub motor built to change that. Its PedalFlow system reads your torque, cadence and speed in effectively real time, so assist builds with your pedal stroke instead of arriving all at once. As a bonus, it also carries a 3-speed gearbox inside the hub that shifts itself in about 0.2 seconds, including at a standstill, so you never have to worry about being in the wrong gear pulling away from the lights. It’s rated at 50Nm and won a Gold Creative Award at China Cycle 2025.

A basic rear hub

Pedal feel. Assist switches on when the cranks turn, can be torque or cadence based.
Gears. Manual derailleur and shifter or single speed.
Drivetrain. Chain, cassette and derailleur to keep adjusted.

Ananda R900

Pedal feel. Assist follows your torque, cadence and speed.
Gears. Automatic 3-speed gearbox inside the hub, shifting in about 0.2s.
Drivetrain. No derailleur. Runs a chain or a belt.

That combination is why the Auren EV5 incorporates the R900 in its new design. It keeps what makes a rear hub good for commuting, a sealed motor and a drivetrain that only carries your effort, and adds a natural ride feel and automatic gears on top. On the EV5 it’s paired with a carbon belt, so there’s no chain to oil.

For more info Ananda R900 motor guide

05

Frequently asked

Mid-drive and rear hub questions, answered.

What's the difference between a mid-drive and a rear hub motor?

Where the motor sits. A mid-drive is mounted between the cranks and drives the chain, so its power goes through the bike’s gears. A rear hub is built into the back wheel and drives the wheel directly, so the chain and gears only carry your effort.

Is a mid-drive or a rear hub better for hills?

It depends on how steep and how long. A mid-drive’s high torque and gearing suit steep, sustained climbs and trails. On commuting hills a rear hub copes well, and an automatic hub gearbox like the Ananda R900 helps on the steeper pinches by dropping to a lower gear.

Which is better for commuting?

For stop-start traffic, bike paths and rolling suburban routes, a rear hub’s strengths count for a lot: it’s simpler, sealed in the wheel, and leaves the drivetrain carrying only your effort, so there’s less to wear out and look after.

Can a rear hub motor eBike have gears?

Yes. Most rear hub eBikes run a standard derailleur and cassette, and newer motors like the Ananda R900 put a 3-speed automatic gearbox inside the hub itself.

Does a rear hub eBike need less maintenance?

The drivetrain usually does. The motor drives the wheel rather than the chain, so the chain or belt and gears only carry your effort and wear more slowly than on a mid-drive.

Do rear hub motors feel less natural to ride?

They have a reputation for it, mostly from hub bikes that switch assist on whenever the cranks turn. A hub that reads how hard you’re pedalling, like the Ananda R900, builds assist with your pedal stroke instead, which feels much closer to riding with stronger legs.

What's the difference between a torque sensor and a cadence sensor?

A cadence sensor detects that the cranks are turning and adds a set amount of assist. A torque sensor measures how hard you’re pushing and scales the assist to match. Torque sensing is what gives an eBike a natural pedal feel.

Why do e-mountain bikes use mid-drive motors?

Steep, loose climbs need high torque at low speed, and a mid-drive can use the bike’s low gears to multiply its torque. It also keeps weight low and central, which helps the bike stay balanced on technical ground.

Does a mid-drive wear out the chain faster?

Yes. The motor’s power runs through the chain, cassette and chainring on top of your own, so they wear faster than on a bike where the motor drives the wheel. Riders on mid-drives tend to replace drivetrain parts more often.

Is it harder to fix a flat on a rear hub eBike?

A little. The rear wheel carries the motor and its cable, so taking it out takes a few more steps than on a normal bike. Front flats are no different.

Are mid-drive eBikes more expensive?

Usually. A mid-drive motor is a more complex unit and needs a frame built around it, so bikes with one tend to cost more than comparable rear hub bikes.

Which gets better range, a mid-drive or a rear hub?

Battery size, terrain, rider weight and assist level make a bigger difference than motor position. On steep, hilly rides a mid-drive can be more efficient because it can use the bike’s low gears.

Can a mid-drive eBike run a belt drive?

Only with the gears inside a hub or gearbox, because a belt can’t run on a derailleur. With a rear hub motor that has its own gearbox, like the R900, the drivetrain outside is a single speed, so a belt fits naturally.

How powerful can an eBike motor be in Australia?

A pedal-assist eBike can have up to 250W continuous rated power, with assistance cutting out at 25km/h, under the EN15194 standard. That applies to mid-drives and rear hubs alike.

What motor does the Auren EV5 use?

A rear hub Ananda R900, rated at 250W and 50Nm, with a 3-speed automatic gearbox inside the hub and a carbon belt drive.

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