Mid Drive vs Hub Drive Electric Bikes?

[jonathon]

I am trying to decide between mid motor and hub motor for an ebike build, what are differences between the two systems?

 

[Anton]

Mid Drives:

With a mid motor, an ebike’s weight is well balanced so a large torque can be delivered to the rear wheel when going up hills. Mid motors are best for mountains and regions where you will be climbing steep hills.

Hub Drives:

Hub motors for are easier to install, but they are better suited for ebikes that are going to be ridden in flat areas.

Efficiency:

The transmission efficiency between an ebike mid motor and an ebike hub motor is exactly that same.

 

[HillAversion]

I think the big difference is that a mid drive motor powers the bike through the gears on the back wheel, so they can leverage that gearing advantage just as a rider's legs would do. It's a big advantage for hill climbing, but also in other situations. It's also a lot easier on the motor.

That said, mid-drive motors are more complicated to install. You might check out some YouTube videos to get an idea of the process. There are a million of 'em.

 

[Jimish32]

Mid Drives:

With a mid motor, an ebike’s weight is well balanced so a large torque can be delivered to the rear wheel when going up hills. Mid motors are best for mountains and regions where you will be climbing steep hills.

Hub Drives:

Hub motors for are easier to install, but they are better suited for ebikes that are going to be ridden in flat areas.

Efficiency:

The transmission efficiency between an ebike mid motor and an ebike hub motor is exactly that same.

well i'll add,

Maintenance: Because they are located near the bike's drivetrain. This can make them more prone to wear and tear. Hub motors, on the other hand, are generally easier to maintain because they are located in the wheel and require less maintenance.

Weight: Hub motors tend to be heavier than mid-drive motors because they are located in the wheel. Mid-drive motors, on the other hand, are typically lighter because they are located in the frame.

Location: The biggest difference between a mid-drive and a hub motor is their location on the bike. A mid-drive motor is located at the bottom bracket area, which is the part of the bike where the pedals attach. A hub motor is located in either the front or rear wheel.

 

[munirider]

well i'll add,

Maintenance: Because they are located near the bike's drivetrain. This can make them more prone to wear and tear. Hub motors, on the other hand, are generally easier to maintain because they are located in the wheel and require less maintenance.

Weight: Hub motors tend to be heavier than mid-drive motors because they are located in the wheel. Mid-drive motors, on the other hand, are typically lighter because they are located in the frame.

Location: The biggest difference between a mid-drive and a hub motor is their location on the bike. A mid-drive motor is located at the bottom bracket area, which is the part of the bike where the pedals attach. A hub motor is located in either the front or rear wheel.

It's not the location that makes a hub motor heavier it because they are permanent magnet motors and all those magnets are heavy.

 

[munirider]

Mid drives use https://en.wikipedia.org/wiki/Brushless_DC_electric_motor

Lighter weight and more torque.

 

["A"]

For the money, hub drive is better value, less dependent on drivetrain that's designed for human power, without electric motor power output.

 

[Calsun]

I am trying to decide between mid motor and hub motor for an ebike build, what are differences between the two systems?

Biggest difference is the ability to fix a flat tire with a rear hub drive. My first e-bike had a rear hub and I needed to use a different size metric wrench and an adjustable spanner wrench to remove the axle nuts and get the wheel off the bike. My mid-drive replacement bike uses normal 700x28mm tires and the wheels come off by loosening a skewer like a normal bike.

Rear hub drive is less expensive and that is the appeal for the e-bikes selling for less than $2,000.

 

[m@Robertson]

A hub motor is singlespeed since it powers thru the hub of the bike. It is completely independent of the drivetrain, which means that drivetrain is only available for your muscles. On a regular bicycle, try staying singlespeed on a flat land gear. Now try to ride up a hill without shifting. Life sucks, right? Thats why they invented derailleurs. And thats why a mid drive in hills is the default solution unless its a cheap ebike cutting corners.

If you are riding in hills, thats when the mid drive shines. If you stick to pavement, flat ground and low rolling hills, its hard to make a case for a mid drive unless you want to preserve the versatility to occasionally tackle something steep.

Look at all quality e-MTBs and cargo bikes ... they are all mid drives. If you want to see a hub motor in either genre its a budget model. There is no single-speed hub motor in a bicycle wheel that can match the kind of mechanical advantage a drivetrain like this gives you, and only a mid drive can take advantage of it:

But undeniably a mid drive is not the brainless build and ride that you get with a hub motor. The competence ante is raised significantly for the builder.

How To Build a Mid Drive Ebike That Doesn’t Break

Mid drives up the ante on the required competence of the builder. Read this so your bike lasts without things breaking or wearing out early.

talesontwowheels.com

The rider also needs to follow some easy rules.

How To Ride a Mid Drive Ebike Without Breaking It

If you can ride a bicycle you already know how to ride a hub drive ebike. Not so a mid drive. Particularly a powerful one that can tear your chain apart. Fear not. The rules are simple.

talesontwowheels.com

 

[hsdrggr]

Really good info posted by everyone. Only thing I’ll add is that after riding and building both types I really like the mid drive better for all situations. At least the BBSHD is so tune-able and has a very smooth and gradual acceleration ramp. It’s almost like it acts like a torque sensor type bike. Based on pedal pressure my BBSHD has at least a 5mph spread that I can ride within in each PAS setting depending on my pedal effort. If I want I can get a much better workout with my BBSHD bike in a lesser PAS setting (watts shows around 120-150w assist) or I can ride with less effort going up a PAS setting (watts shows 250-350w assist).
With a hub motor it hits a wall in PAS. It either gives you all its power within the PAS setting until it hits it mph wall then drops to zero. Hub motor PAS systems seems to act more like an on/off switch where the BBSHD does not, it varies assist wattage depending on what your legs add. Which is really what assist should be like.
You can also use an eggrider display with the BBSHD and have 2 modes. I set Road mode with 20 watts max and OffRoad with 30 watts max. In Road mode I get 25-30% more mileage out of my battery. Road maxes at 950w throttle, and off-road shows around 1400 watts.
I feel that with a mid drive even when driven mostly in less hilly areas it’s a plus because you have the low end torque in lower gears to effortlessly tackle bridges and taller hills when you encounter them.
As long as you don’t go crazy with the throttle all the time and use a good chain like a KMC e-bike chain you can help minimize excessive driveline wear. But as others have pointed out mid drives do put more pressure and do increase cassette and chain wear. It’s just a cost of having the PROs of a mid drive system.

 

[m@Robertson]

Having built both myself, I ride mid drives regardless of terrain. They are truly a jack of all trades and if you want one bike to be able to handle everything, thats the mid-drive.

... At least the BBSHD is so tune-able and has a very smooth and gradual acceleration ramp. It’s almost like it acts like a torque sensor type bike. Based on pedal pressure my BBSHD has at least a 5mph spread that I can ride within in each PAS setting depending on my pedal effort. If I want I can get a much better workout with my BBSHD bike in a lesser PAS setting (watts shows around 120-150w assist) or I can ride with less effort going up a PAS setting

Interesting you should mention that. The BBSHD is a cadence-based sensor but its settings interface is incredibly rich - as well as opaque and difficult to master. But once you do, it a) behaves NOTHING like a factory-default motor and b) is an amazing companion to a rider who wants to ride like a cyclist and get exercise. All the stuff you hear about how cadence PAS is on/off, laggy and whatnot is out the window when you know how to tune these motors.

Also, if you want to have a geared hub motor that does not have ANY of the common, on/off, laggy complaints of cadence-based PAS: Buy a KT controller and display. KT controllers have what they call 'simulated-torque' PAS which is a sort of stupid way of saying they have a rather sophisticated algorithm for PAS power delivery that engages quickly, provides a big ramp up at slow speed and low crank rpms, which ramps down quickly as speed and cadence increases. You can also dial back the initial power ramp with one of three levels of slow-start which smooth out the power curve. This is why these controllers typically cost $75-$100+ (plus the display) versus ten bucks and a free taillight on AliExpress for some basic POS hub controller.

 

[hsdrggr]

I’ve seen those controllers and noticed that they come in kits with the display. I’ve have one in my cart in Aliexpress for a while but never ordered it. I did not know that they were that feature rich and functioned with a variable assist so to speak. Thank you. I was thinking about using one on my wife’s brand new Aventon Aventure that has a 750w Bafang rear hub. I wanted to unlock its true potential and do some customizing to the settings. Not that she needs it, but what the hell I like tinkering. Or like Tim Allen says “argh argh argh, More Power!”

 

["A"]

I've been converting mid-drive & hub drive ebikes since 2013, over a dozen of them.
I prefer hub-drive because of its simplicity; just as bicycling in general.
Facts are:
1. mid-drive will always cost more.
2. mid-drive will always rely on operational drivetrain to propel the bike.
3. mid-drive will always require more drivetrain maintenance.
4. mid-drive will always be more complicated kit to install on a bicycle.
5. mid-drive will require more frequent drivetrain component replacement (chain, cassette, chainring, freehub body, etc..)
6. Even though you can use gears on the freehub, you're still limited to the range of the cassette, just as hub-drive with range of freewheel.

For people who just want to get out and ride, spend less time on maintenance, hub-drive is much simpler to use and care for.
For those who have money ($3000 or more) for a ebike, that may or may not suit your cycling style, sure, go for it and find out.
Generally, majority of cycling can easily be done on a hub-motor ebike that doesn't cost more than $2000.

I admit, I've spent tens of thousands on ebikes & converting ebikes of many different types of drivetrains, from my experience, a $2000 hub-drive ebike can easily do 90-95% what a mid-drive that's costing thousands more.
I doubt anyone who's spend $5000 or even $7000 on a mid-drive ebike will ever tell you that they wish they had spent less on ebike or equipment and used that money to take longer bike trips or splurge on other things to make riding experience more memorable.
I learned that it's more important to enjoy the time while riding than fuss about what equipment outperforms one another under certain conditions.
I learned that time spend on bike maintenance is better spent on riding.

 

[neutron]

I wonder if the OP ever built his bike? I would imagine that if you asked the question he asked, hub vs mid drive, you may not be ready to tackle such a project. Just a thought.

 

[hsdrggr]

I wonder if the OP ever built his bike? I would imagine that if you asked the question he asked, hub vs mid drive, you may not be ready to tackle such a project. Just a thought.

I don’t think there is really too much difference in difficulty between the two.
Lacing and building a hub motor wheel vs. pulling a bottom bracket and installing a mid-drive. Actually, most cyclists don’t want to tackle building wheels, so the mid drive would be easier. The only issue with the mid drive is that you need some mechanical aptitude and knowledge of parts availability to get the chain-line right and torque plates for the dropouts. And there is enough info in forums, blogs and videos to get that info too. As for tuning a BBSHD, there are several good guides out there too. So IMO not much difference in difficulty, just having a good mechanical understanding is needed in building a mid-drive bike.

 

[hsdrggr]

For those who have money ($3000 or more) for a ebike, that may or may not suit your cycling style, sure, go for it and find out.
Generally, majority of cycling can easily be done on a hub-motor ebike that doesn't cost more than $2000.

“A”
I just built this mid-drive e-bike for $2044, and it even has a CVT/CVP IGH rear hub. It’s all brand new including the frame. So it’s not that expensive. I have everything listed in the Build Section of this forum. As I have time I will update all the parts I had listed with links to make it easier for others to source the parts without a lot of work. After building and riding a mid drive, I don’t think I’ll go back to hub motors for a daily rider. However I probably will still use my 500w hub bike for touring because it’s good on battery usage and I already have it outfitted with all my accessories.

 

["A"]

“A”
I just built this mid-drive e-bike for $2044, and it even has a CVT/CVP IGH rear hub.

Since it's just built, you can't be certain about the maintenance required or how well it would hold up over period of time.

I see that it is a single speed, doesn't really take advantage of the drivetrain gearing for hills that mid-drive is known for.
Have you tested its hill climbing ability?

Is this your first build? does the cost of $2044 include the donor bike & battery?

What is the battery capacity?

 

[m@Robertson]

Facts are:
... <snip> ...

These absolutes are not necessarily true (or the distinction noted is effectively meaningless, or even wrong). Its an old argument with you and while you may be looking to go at it yet again, I don't think it serves the uninitiated to engage in yet another jihad on this subject. You have a sharp bias that does a disservice to people who are looking for even-handed advice.

A more accurate response is that each motor type has its strengths and its weaknesses; I boiled those down into a single sentence in Post #9 rather than going on and on about it (this is a dead thread with no one actually asking questions so brevity on that front is warranted).

While I may prefer mid drives, I recognize they aren't for everyone, and hub motors can be good enough for many. But people who come along looking for answers and find this thread are spending real money. They deserve straight answers lest they throw a pile of it away on something that won't serve their needs.

 

[m@Robertson]

I just built this mid-drive e-bike for $2044,

I'll let @hsdrggr get into his own details (look for his thread on this forum). Lets shine a light on the reality of costs in general.

Its very common in DIY circles to use a Mongoose Dolomite (excellent chromoly frame) as a donor bike. $450 on Amazon. Then add an all-inclusive BBSHD kit. $670 if you go no-frills and use the steel chainring and standard crankarms. Now add a quality battery - Here I am spending much more than many would with some junk battery like one from UPP. My call would be from Bicycle Motorworks, which is a made-to-order-in-Pennsylvania pack with name brand cells and a high quality BMS. A 52v, 16.8ah Molicel pack with a 60a continuous BMS is $540.

Lets add $35 for a battery bag, which is complete with cable egress and ingress ports for easy hidden wiring.

Spend $12 for a programming cable and $0 to download the Speeed app for your phone and you can turn that 1500w motor into a gentle, comfortable pedalec that, if you want it to, will give you measured, ramped assistance that never exceeds 400w peak. Detuned like that the motor will last forever. Same with the drivetrain. Or ramp it up to peak near 950w for steep hills and the motor will still last longer than you will, and you can still expect a chain to last 2000 to 3000 miles if you treat the bike right (see 'how to ride' link in Post #9 above).

BBSHD Performance Settings (slightly refined)

In BBSHD Programming for the Pedaling Cyclist, I laid out what my preferred settings were for my ebikes. I have settled upon them after a fair bit of tinkering over time. Since that was published, …

talesontwowheels.com

So $450+670+540+12+35=$1707 for a complete powerhouse bike with top drawer DIY motor components and a sophisticated pedal assist system that borders on being infinitely adjustable (plus it has a throttle). Its only weakness is cheap bicycle components, which any cheap Chinese ebike also suffers from. You can upgrade those a bit here and a piece there as budget permits (start with the brakes).

 

["A"]

These absolutes are not necessarily true (or the distinction noted is effectively meaningless, or even wrong). Its an old argument with you and while you may be looking to go at it yet again, I don't think it serves the uninitiated to engage in yet another jihad on this subject. You have a sharp bias that does a disservice to people who are looking for even-handed advice.

A more accurate response is that each motor type has its strengths and its weaknesses; I boiled those down into a single sentence in Post #9 rather than going on and on about it (this is a dead thread with no one actually asking questions so brevity on that front is warranted).

While I may prefer mid drives, I recognize they aren't for everyone, and hub motors can be good enough for many. But people who come along looking for answers and find this thread are spending real money. They deserve straight answers lest they throw a pile of it away on something that won't serve their needs.

Not necessarily true? do you live in reality? no matter how old you think they are, they are still true.
What serves the uninitiated is saddle time not conversion time or maintenance time.
Less time spent on working the bike more time spent riding; that's what serves the uninitiated. That's not a bias, that's reality.

More accurate response? humans have the ability to adapt to machines and operate machines to suite their needs.
You want to have better performance, learn to ride; that will always be more efficient than spending thousands on equipment that can only offer few seconds faster on a climb. Cycling is all about efficiency, whether it be from human body or mechanical, learn to ride the bike you have and you don't have to spend thousands more.
Not only hub-motor can be good enough some many; they are good enough for the majority at lower cost.
Is that straight enough answer?

I'll let @hsdrggr get into his own details (look for his thread on this forum). Lets shine a light on the reality of costs in general.

So $450+670+540+12+35=$1707 for a complete powerhouse bike with top drawer DIY motor components and a sophisticated pedal assist system that borders on being infinitely adjustable (plus it has a throttle). Its only weakness is cheap bicycle components, which any cheap Chinese ebike also suffers from. You can upgrade those a bit here and a piece there as budget permits (start with the brakes).

If we're scraping the bottom, sub $1K ($800 even) complete class-3 hub-motor ebike can offer most of the performance of your $1707 conversion, without all the mechanical & electrical work hours.