Mid Drive or Hub Motors

 
electric motor examples

We’re often asked at e-Boom Electric Bike store, “Which is best? Mid-drive or hub motors?”

Our typical response, “Depends upon your personal preference.”

The debate is like Apple vs Android. Both are great products and have loyal followers who deeply believe that their preference is best.

So, we’ll let you decide by providing information on each motor type, mid-drive and hub. And, then we highly recommend that you test ride an e-bike with each type of motor. That way you can experience them first-hand (or foot in this case).

Bikes at e-Boom Electric Bike Store

Rear Hub Motors:

Easy Motion (Evo Eco, Easy Go Street, Evo City Wave, Evo City, Evo Street, Evo Cross, EasyGo Volt, Nitro)

Magnum (Ui6, Cruiser, Metro, Metro Plus, Peak, 48v folding, 36v folding, Ui5)

Surface 604 (Boar Fat, Shred, Rook, Colt)

E-Lux (Newports, Tahoes)

Front Hub Motors:

Smartmotion (Vista folding)

Mid-Drive Motors:

Bulls (Lacauba Evo E8, Sturmvogel E-Evo, Monster EFS Fat)

Easy Motion (Rebels)

What’s a Mid-Drive Motor?

Mid-drive motors are electric motors mounted at the bottom bracket of the bicycle. They connect directly to the bike’s cranks and gears. A mid-drive motor powers through the bike’s drivetrain which enables the motor to help with long and steep climbs and power up to high speeds on flat roads.

What’s a Hub Motor?

Hub motors are electric motors that are housed inside the hub of either the front or rear wheel of the bike. They are the most versatile and easiest way of converting a bike or trike over to an electric assist. Hub motors don’t put additional stress on a bike’s existing drivetrain and operate independently of the pedal transmission.

There are three general types of hub motors:

  • direct drive that uses the entire hub as the electric motor
  • geared hub motors that have a small internal motor with gears that drive the hub shell
  • all-in-one hub systems that house all the e-bike components (motor, battery and controller) in the hub

 

Pros and Cons of Mid-Drive Motors

bosch mid drive motor
A Bosch system mid-drive motor

Mid-Drive Pros
Mid-drive systems are good at climbing long, steep hills, because the small motor working the drivetrain can do this with excellent efficiency. This is a good feature if you ride in areas that have consistently long and steep climbs.

Mid-drive motors are great for off-road mountain biking. The motor weight is low and centered, so it has minimal effect on handling, even on full suspension mountain bikes.

Mid-drive motors can also leverage the higher gears of the drivetrain to cruise along at high speeds on flat roads.

Mid-drive motors mounted on or near the bottom bracket allow you to remove the front or rear wheel easily without worrying about motor wires or hardware.

Mid-drive systems use a chain, cogs and derailleur drivetrain, and some of these systems are compatible with internally geared hubs and belt drives.

Mid-Drive Cons
There is more wear on the drivetrain and components of the bike since the mid-drive motor transfers power through them. You may have to replace these parts and components more frequently.

Most mid-drive systems have a single chainring which limits the gear range. This works okay for most riding conditions, because the motor speed makes up for the missing gears.

If you’re riding on roads where maintaining a steady speed regardless of the hill grade is important, then a mid-drive motor offers no advantage over a hub motor.
 

Pros and Cons of Hub Motors

rear hub motor
A rear hub motor on
the Surface 604 Rook

Hub Motor Pros
Hub motors are independent from the bike’s drivetrain system. So, if you’re out on a ride and a chain breaks or a derailleur gets bent, the hub motor can still propel you home. A mid-drive motor is completely dependent upon the drivetrain, so you can no longer use the motor once anything breaks.

The use of the hub motor provides less wear and tear on the bike’s drivetrain (chain, cogs and derailleur) since you’re not putting as much pedal stress on it as the mid-drive motors.

Any type of gearing system (drivetrain) can be used (traditional gears and internal geared hubs with a chain or belt drive).

The drivetrain system on a hub motor can handle higher power levels (250-750 watts) without limitations. A mid-drive system can’t handle the higher power levels without extreme wear and tear on the drivetrain, wheels, spokes, etc.

For rear wheel hubs, the rider’s weight is over the back wheel, so there’s less tendency to spin on loose road conditions.

With front wheel hub motors, you create an all-wheel drive bike, because the motor drives the front wheel and you power the rear wheel with pedal power.

Some direct drive rear hub motors can provide regenerative braking.

Hub Motor Cons
Some riders do not like the feeling of being “pulled” by the motor.

Rear hub motors can be cumbersome to install or remove because of gears, chain, derailleur, etc.

The higher torque hub motors (the more powerful ones) need larger spokes and sturdier rims.

Some can make long, steep hill climbing a bit slower on non-performance level bikes.

Front hub motors are generally in a lower power range (250 to 350 watts), because the front fork of the bike doesn’t provide as much structural platform for the high-powered motors.
 

Hub Motor Types

front wheel hub motor
Front wheel hub motor on
a folding e-bike.

Geared vs Direct Drive Hub Motors

Geared Hub – The motor spins internally at a high RPM, and a gear transmission inside reduces this to a low RPM for the bike wheel. Almost all geared motors include a freewheeling clutch so that the wheel will spin freely and not turn the motor when you’re coasting.

Direct Drive Hub – The hub is the motor. There is no internal gearing. These motors tend to be larger and heavier than a geared hub motor. They don’t have a clutch which can allow regenerative braking, but this also means there is some motor drag while coasting.

What is Regenerative Braking?
This is only produced from a direct drive hub motor. Regenerative braking uses the motor as a brake to assist in slowing down the bike without using the bike’s mechanical brakes. This can give you about a 3% to 8% increase in battery range from recaptured energy. It also helps reduce wear and tear on the bike’s brakes. The only negative is that it does slow you down quite a bit when coasting.

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