50nm mid drive vs 50nm hub drive

A mid drive motor is not better engineered than a hub motor. There is really not much to engineer, it is a pretty mature and simple design.

The difference is:

-Hub motors rpm completely depends on your speed(since there is no gearing in between the wheel and the motor) at low speeds the rpm drops, the motor runs in the inefficient band and its power output falls significantly below its peak.

-With a mid drive rpm is completely dependent on cadence and when climbing if the gear ratio is right one can keep the cadence hence rpm in the motor's efficient range where it can also produce close to its peak output.

Yes it is simple physics and it is all about output power vs rpm graph not the peak numbers. Ebike companies don't give you that, instead advertise those meaningless peak numbers of Torque etc.


So here is the conclusion,
On very steep hills with the right gearing you can keep the cadence of a mid drive in the efficient band hence can expect mid drive to be more efficient than a hub motor.

Otherwise, hub motor will not suffer the losses at the drivetrain and be more efficient than the mid drive.


I struggle when people write about "hub" drives discounting completely the potential for gear driven hub drives. That omission skews most of their comments into uselessness.
 
@Johnny,
If we compare apples to apples (a 250 W hub motor to a 250 W mid-drive one), it is clear the hub-drive motor is a very poor climber. You have given the answer to the question "why" yourself. When riding a mid-drive motor against a steep incline, the cyclist and the motor cooperate, and their combined effort is amplified by the drive-train. It is easy to get on gearing/cadence to keep the motor efficient as well. Mid-drive motors are designed to be especially effective at the low end (it is the very idea of an e-MTB motor). Additionally, mid-drives can produce bursts of power.

A hub-drive motor works with constant power and is not amplified by the drive-train. You cannot ride uphill fast to get such a motor into the optimum rpm either. Moreover, hub-drive motors tend to overheat while climbing.

You might say "who needs a 250 W hub-drive motor?" Putting regional/legal matters aside, I would say a 750 or 1000 Watt hub-drive motor is heavy. To maintain a good range, you need a large battery. That makes the hub-drive motor e-bike very heavy. Climbing means increase of the potential energy (equals elevation gain times the total rider/bike/cargo mass times the gravity) so the heavier e-bike is, the bigger battery you need, that makes the bike even heavier, then...

For these reasons, no respected e-MTB brand will ever use a hub-drive motor anymore. A 250 W nominal Brose S Mag or Yamaha PW-X2 motor beats hub-drive motors with torque, peak power, climbing ability, light weight and reasonable sized battery.
 
I can say that 90% of hub motor's torque value is far from real values. For example Bafang claimed to have 80 NM torque so does Rad power but Actual torque is somewhere around 35-40 Nm torque.
Only trust the torque of reputable brands like Bosch and Shimano.

High torque will be achieved by speed reduction gears. But in geared hub motors they only have single gear ratio so If a hub motor has 80 Nm torque it can't have a high top speed. Maybe top speed will be only 8mph (or they need to have a massive size hub motor). Mid-drives can achieve higher torque by reducing the speed (which increases force).
 
@Stefan Mikes

I think we all agree that for emtb's mid drives are the better choice because of the reasons in my post.

But it doesn't mean that as a motor mid drives are better engineered, it is the placement of the motor that makes the difference.
 
@Stefan Mikes

I think we all agree that for emtb's mid drives are the better choice because of the reasons in my post.

But it doesn't mean that as a motor mid drives are better engineered, it is the placement of the motor that makes the difference.
Better engineered? I think they are better engineered and more sophisticated. But it doesn't mean they are better for every situation. If you are looking for an e-bike just for cruising and don't need to do lots of hill climbing then you don't need features that comes with mid-drive motors. A hub motor will even outperform a mid-drive motor.

But mid-drive motors come with more advanced gearing, more advanced controller and more sophisticated sensors.
 
If you are serious about talking torque, I think it might be in your best interest to play with Grin's spreadsheet long enough where you can get some commonly accepted data to base future decisions on (without wading through uninformed opinions or agendas - just the facts). Find your motor, plug it in, and see what comes of it. Then compare it to whatever you want, including direct drive, geared drive, and mid!

 
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If you are serious about talking torque, I think it might be in your best interest to play with Grin's spreadsheet long enough where you can get some commonly accepted data to base future decisions on (without wading through uninformed opinions or agendas - just the facts). Find your motor, plug it in, and see what comes of it. Then compare it to whatever you want, including direct drive, geared drive, and mid!

I found Grin's calculator to be an invaluable tool in selecting the hub motor for my DIY ebike conversion. The ebike climbed our local steep hills just as the simulator predicted, using just about the same amount of power. I, too, would recommend this to anyone that wants to make 'apples to apples' comparisons between motors.
 
Are we talking Brose, Yamaha, Bosch, Shimano, Mahle or the Chinese cr*p? :D
P.S. As soon as I hear "Bafang", I open the fire!

Did I say Bafang ?

Dapu, TDCM, Neodrive(and probably Grin's offerings) are all high quality hub motors. Some of them already come with a high quality torque sensor + controller. Their rated values seem to be spot on, not overrated.

Putting the torque sensor and controller in the same enclosure doesn't make mid drives more sophisticated in any way. You can start with a quality hub motor and pair it with an asi controller and a good torque sensor and you end up with a system that will be more powerful, efficient and just as smooth if not smoother than those mainstream mid drive offerings you have mentioned.


I think labeling things as "Chinese cr.p" is unfair since most of the big companies like Brose, Bosch do manufacture (at least some of their components if not the whole product) in China.
As for Bafang, they are trying to make motors as cheap as possible so it is expected that they will not match the smoothness/reliability of the mainstream.
 
Brose manufacture in Germany, Bosch in Slovakia. TDCM is Taiwanese company. And for Dapu their quality go down so much in recent years. After their top management quit, I don't hear lot of good reviews about dapu motors. Long time Dapu users are slowly going away from Dapu. I feel so sad for it as I loved Dapu motors before.
 
As the original poster of this thread, I would like you to know I have sold my Aventon Pace 500 and ordered a Specialized Como 4. Thanks for the information you provided.

Looking forward to the arrival of the Como 4 and will let everyone here know my thoughts on the new bike.

Congrats on your new Como... you will enjoy the mid-drive power delivery and balance.
 
I am currently riding an Aventon Pace 500 which I am generally pleased with. A couple annoying features though have me now looking at a mid drive bike.

The Aventon is a 500 watt, 48 volt, 50 nm, 8 speed rear hub motor ebike that is capable of ascending every hill I've tried even with my 250 pound weight. Albeit sometimes slowly.

I dislike the abrupt on-off feel of the motor due to the cadence sensor and the inability to pedal constantly in PAS 1 without going 11-12 mph.

I also dislike that the assist doesn't start helping from a stop until a pedal revolution or so.

I do like the relaxed, upright riding style as I'm 63 with some health issues.


Looking at Trek mid-drive ebikes with the 2020 Bosch Active Line Plus motor and 50 nm torque (Verve+ 3).

Or a 2020 Specialized mid-drive ebike with Brose 1.2e motor and 50 nm torque (Como 3).

Would either of these two mid drives perform as well or better on hills as the Aventon?

Do I need to go to the Electra Path Go and it's Bosch Performance line motor with 65 nm torque?

Or the Specialized Como 4 with its Brose 1.3 motor and 75 nm torque?
Nope. Bosch is very weak, and it's interesting how many come in looking for Aventon Pace 350 and 500's after they've tried the more expensive Treks with Bosch on them. And they love the throttle, and no complaints about how it activated. Mostly they are just thrilled to have a throttle. And most don't mind the cadence sensing response, and those who do, aren't willing to drop another $ 1000 to get the smoother response from a much weaker motor. As always there are trade offs, and pros and cons on everything. They frequently cite the added power from The Aventon motors as most important to them. Although I have witnessed a few 70 and 80 something's prefer the Bosch and perfectly happy with slower speeds and staying on mostly flat terrain. We are also pretty flat here in Illinois.
 
As the original poster of this thread, I would like you to know I have sold my Aventon Pace 500 and ordered a Specialized Como 4. Thanks for the information you provided.

Looking forward to the arrival of the Como 4 and will let everyone here know my thoughts on the new bike.
Wow that's a lot more dough than the Aventon, eh ? . Hope you really enjoy it ! Definitely an upgrade over an Aventon. Over time I anticipate many first time ebike buyers/ riders will refine their tastes and graduate to more expensive ebikes like the Como's or Vados or Yamahas etc. They will likely find too, they didn't use or need the throttle all that much, and maybe even prefer the experience of torque sensing, and be willing like you to shell out more dough for it.
 
Nope. Bosch is very weak, and it's interesting how many come in looking for Aventon Pace 350 and 500's after they've tried the more expensive Treks with Bosch on them. And they love the throttle, and no complaints about how it activated. Mostly they are just thrilled to have a throttle. And most don't mind the cadence sensing response, and those who do, aren't willing to drop another $ 1000 to get the smoother response from a much weaker motor. As always there are trade offs, and pros and cons on everything. They frequently cite the added power from The Aventon motors as most important to them. Although I have witnessed a few 70 and 80 something's prefer the Bosch and perfectly happy with slower speeds and staying on mostly flat terrain. We are also pretty flat here in Illinois.
the bosch has far more torque then then either aventon. it just sounds like people want a throttle and no really plan on riding the e bike like a bike. the quality evel between the two is night and day.
 
the bosch has far more torque then then either aventon. it just sounds like people want a throttle and no really plan on riding the e bike like a bike. the quality evel between the two is night and day.
I think those bikes that use Bosch will be expected to be more refined and upscale since people pay so much for the motors! You can get away with cheaper components on a 28 mph ebike with a hub motor that has a throttle because the emphasis is the throttle and not the mechanics of user pedaling experience. Weight, rider's input, and maneuverability takes a back seat to ease of use and speed limit! As an example, the emphasis may be on providing a cushioned ride versus getting the best tires that will dictated how well a bike handles on curves, or its traction on gravel and wet surfaces!
 
I think those bikes that use Bosch will be expected to be more refined and upscale since people pay so much for the motors! You can get away with cheaper components on a 28 mph ebike with a hub motor that has a throttle because the emphasis is the throttle and not the mechanics of user pedaling experience. Weight, rider's input, and maneuverability takes a back seat to ease of use and speed limit! As an example, the emphasis may be on providing a cushioned ride versus getting the best tires that will dictated how well a bike handles on curves, or its traction on gravel and wet surfaces!
exactly. the lowewr end bikes are geared towards causal riders. who knows if they will even keep riding them. I bet within a year there will be a ton of used bikes for sale.
 
Priorities guys. Let's try to keep in mind there are a lot of them, and stop this B.S. of mine is bigger/better or I'm smarter. It's really unbecoming.
 
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