Enviolo or Rohloff?

[Daffyh]

I live in a very mountainous area and am finding my current E Bike a bit underpowered. I am looking at a line of mid drive motors that increase my torque from 85Nm to 120Nm for the same wattage. We do not do single track or fully loaded long distance (+350 mile) touring, but do ride our bikes various steep roads and fire trails. My question then is on the type of hub to go to. My two choices are the Envilio or the Rohloff. I am looking for some input from riders familiar with either or both.
Thanks in advance.

I have owned and used both Rolhoff is way better for hills due to its wider gear range.

 

[mschwett]

it’s certainly possible to have the same power, but different torque, since the torque produced can vary by RPM.

motor A produces 100nM at 100RPM. that’s approximately 1000w. at 50RPM it only produces 80nM. peak power is at 100 RPM.

motor B produces peak torque of 200nM at 50RPM, that’s approximately 1000w. by 100RPM, the torque has dropped to 100nM or less. that’s still approximately 1000w. it is still a 200nM peak motor, and also still a 1000w motor.

this is why automobile enthusiasts refer to the “area under the curve” of a dyno plot, because as you accelerate your rate of acceleration is based on the Torque produced at each RPM until shifting. and the higher RPM you can sustain torque at, the more powerful the engine, and you can also take advantage of gearing.

 

[Stefan Mikes]

it’s certainly possible to have the same power, but different torque, since the torque produced can vary by RPM.

motor A produces 100nM at 100RPM. that’s approximately 1000w. at 50RPM it only produces 80nM. peak power is at 100 RPM.

motor B produces peak torque of 200nM at 50RPM, that’s approximately 1000w. by 100RPM, the torque has dropped to 100nM or less. that’s still approximately 1000w. it is still a 200nM peak motor, and also still a 1000w motor.

this is why automobile enthusiasts refer to the “area under the curve” of a dyno plot, because as you accelerate your rate of acceleration is based on the Torque produced at each RPM until shifting. and the higher RPM you can sustain torque at, the more powerful the engine, and you can also take advantage of gearing.

I cannot agree with you. The e-bike mid-drive motor torque is given for a reference chainring. It is the torque at the chainring.
Two chainrings for two e-bikes of identical drivetrain gearing and wheel size -- moving at the same speed -- will rotate at the same angular speed. We are talking e-bikes not cars here.

It is possible to find technical information at Specialized Support pages (I am sure you can find it @mschwett) where Max Mechanical Motor Power and Torque are given for 2.0E, 2.0, and 2.2. motors. You will see a direct relationship between the max motor power and the torque specified by the manufacturer.

 

[Stefan Mikes]

An additional information:
Austria is the only EU country that limits the maximum mechanical motor power to 600 W in her e-bike regulation. Therefore, the Specialized 2.2 motor produces up to 565 W mechanical power. Bosch CX Gen 4 must be at least that strong. Yet, Specialized gives 90 Nm but Bosch specifies 85 Nm. A different reference chainring? Or, Bosch motor producing less power maybe?

All the torque specifications for e-bike motors are for marketing. In case of Europe and mid-drive e-bike motors the torque is given to avoid talking of the max motor power, as the nominal motor power in Europe shall be 250 W but the motors are actually far stronger than that.

The bottom line is: Never look at the torque spec. Look at the max mechanical motor power. A more powerful motor will be a better climber if we are talking mid-drives.

 

[mschwett]

I cannot agree with you. The e-bike mid-drive motor torque is given for a reference chainring. It is the torque at the chainring.
Two chainrings for two e-bikes of identical drivetrain gearing and wheel size -- moving at the same speed -- will rotate at the same angular speed. We are talking e-bikes not cars here.

It is possible to find technical information at Specialized Support pages (I am sure you can find it @mschwett) where Max Mechanical Motor Power and Torque are given for 2.0E, 2.0, and 2.2. motors. You will see a direct relationship between the max motor power and the torque specified by the manufacturer.

no, you’re not getting my point. one e-bike with 50nm peak torque torque may generate that torque at high RPM, and thus be capable of accelerating from, say, 25 to 26 mph, at 100rpm at the chainring. another e-bike, with the same tires and in the same gear, may NOT be capable of accelerating at 25 mph / 100rpm because it does not produce its peak torque at 100rpm. perhaps it only produces 40nm at 100 rpm. it is 20% less power. while i would agree that the torque curve of an electric motor is much flatter than a combustion engine, it is not completely flat.

 

[mschwett]

all these motors generate nearly the same peak torque / but at very LOW rpm.

since power = torque x RPM, measured at the chainring, tell me which motor has the highest power? i’m sure you can see that they are not the same.

 

[Cybersnow]

Great point. In checking with Bafang, the M620 is configured to take a chain drive as well as the belt pulley. You are correct fro a cost standpoint in that i would have to have the rear wheel replaced as well as as all the Sram parts. If there isnt the clearance for the chain and derailleur then we are talking a new frame….$$$

 

[Gionnirocket]

Great point. In checking with Bafang, the M620 is configured to take a chain drive as well as the belt pulley. You are correct fro a cost standpoint in that i would have to have the rear wheel replaced as well as as all the Sram parts. If there isnt the clearance for the chain and derailleur then we are talking a new frame….$$$

My bike was originally built as a 10s and then changed to the Rohloff by Zen at the time of purchase. Since many upgrade to a Rohloff after owning the bike a while, you're probably dealing with dimensions that fall within a standard.
Personally... I've left the derailleur in the rear view mirror forever.

 

[Stefan Mikes]

all these motors generate nearly the same peak torque / but at very LOW rpm.

since power = torque x RPM, measured at the chainring, tell me which motor has the highest power? i’m sure you can see that they are not the same.

View attachment 172170

This is a very outdated chart.
Now, please tell me: Which exactly Brose motor? What year?

 

[scrambler]

The torque figure given by mid drive motor manufacturers is related to the motor output at the chainring. If the internals of some motor rotate faster, it is equalized by the internal motor gearing and the chainring to the same angular speed that drives the e-bike transmission.

Let me give you a good example:
Old Bosch mid drive motors had the output (at the spindle) rotating at the speed 2.5 times faster than the motors of today. We could choose a motor of Gen 1 and another of Gen 4, each having the same output power.

To have the same practical output torque, the old motor was using a 16T chainring while the modern motor would use a 40T chainwheel. The angular speed at each chainring for given motor power was the same on both chainrings because either had a different diameter

The flaw in your reasoning is using the formula with rpm. It is the angular speed ω that is used in the torque/power calculation, and the angular speed depends on the rpm and the power output diameter.

For two e-bikes with the same gearing and wheels moving at the same speed the angular speed at the chainring (the driving wheel) is the same.

I was just commenting on your remark that with the same power comes the same torque, and which is incorrect for an electric motor.

On my bike with a fully controllable controller, I can set different torque levels for the same Output power.
This is done as I mentioned by the controller modulating the Phase amps, providing more phase amps at a lower voltage for modes requiring more torque, or using less Phase amps and more voltage for modes requiring less torque (an more speed).

Whether a specific motor like the Bosch can do that I do not know, as it all depends on the controller. But as far as I know the physics allow for different torque output for same power.

 

[mschwett]

This is a very outdated chart.
Now, please tell me: Which exactly Brose motor? What year?

stefan, it doesn’t matter exactly what motor, or how outdated the chart is. the simple fact is that even modern electric motors don’t produce exactly the same amount of torque at different speeds. obviously you’d have to agree that if a motor produces 100nM at 75rpm it is unlikely to also produce 100nM at 150rpm (twice the power) or 300rpm (four times the power) for any sustained length of time.

here is another one :

you can clearly see that torque is nearly constant from 20-60 RPM, so the level of power is a straight line sloping up. past 60rpm, power starts dropping at different rates which clearly illustrates that torque is no longer the same. if torque was fixed and power = torque x speed, the power curve would always be a straight line, which it is not.

 

[Tom@WashDC]

Personally... I've left the derailleur in the rear view mirror forever.

Me too...

 

[Stefan Mikes]

stefan, it doesn’t matter exactly what motor, or how outdated the chart is. the simple fact is that even modern electric motors don’t produce exactly the same amount of torque at different speeds. obviously you’d have to agree that if a motor produces 100nM at 75rpm it is unlikely to also produce 100nM at 150rpm (twice the power) or 300rpm (four times the power) for any sustained length of time.

here is another one :

View attachment 172175

you can clearly see that torque is nearly constant from 20-60 RPM, so the level of power is a straight line sloping up. past 60rpm, power starts dropping at different rates which clearly illustrates that torque is no longer the same. if torque was fixed and power = torque x speed, the power curve would always be a straight line, which it is not.

I think you are arguing with someone else

• The OP said "Two different mid-drive e-bike motors of the same wattage, one producing 50 Nm and another 120 Nm". My answer was "This cannot happen". Not for manufacturer rated max values.
• There is no doubt any motor has its maximum torque (and power!) at some cadence. Isn't is related to the motor efficiency at different rotational speed, too?
• I cannot accept you are illustrating your arguments with charts, which are obviously Bosch marketing material. Each charts mentions "Brose". What Brose, exactly? Because my Brose TF (Specialized 1.2s) was already available in 2017, and it has 90 Nm at 520W, at least rated.

 

[mschwett]

I think you are arguing with someone else

• The OP said "Two different mid-drive e-bike motors of the same wattage, one producing 50 Nm and another 120 Nm". My answer was "This cannot happen". Not for manufacturer rated max values.
• There is no doubt any motor has its maximum torque (and power!) at some cadence. Isn't is related to the motor efficiency at different rotational speed, too?
• I cannot accept you are illustrating your arguments with charts, which are obviously Bosch marketing material. Each charts mentions "Brose". What Brose, exactly? Because my Brose TF (Specialized 1.2s) was already available in 2017, and it has 90 Nm at 520W, at least rated.

sorry stefan, but you are incorrect. your first bullet point “this cannot happen” is factually wrong, regardless of what charts you agree or disagree with. it can, and does happen, as the basic math and physics dictates. motors produce different amounts of torque at different speeds. some make torque at lower RPM, some at higher. this can lead to the same wattage, but different peak torque. which motors have these characteristics in real life, i could not care less, and it is not germane.

no need to reply, i have had enough of “pissing into the wind” as we call it here.

 

[Stefan Mikes]

sorry stefan, but you are incorrect. your first bullet point “this cannot happen” is factually wrong, regardless of what charts you agree or disagree with. it can, and does happen, as the basic math and physics dictates. motors produce different amounts of torque at different speeds. some make torque at lower RPM, some at higher. this can lead to the same wattage, but different peak torque. which motors have these characteristics in real life, i could not care less, and it is not germane.

no need to reply, i have had enough of “pissing into the wind” as we call it here.

You have never referred Mark to the maximum torque as advertised by manufacturers with the relation to the advertised motor power.

If a brand A says "Our mid-drive motor delivers 50 Nm and has a nominal power of 750W", and
The brand B says "Our mid-drive motor delivers 120 Nm and has a nominal power of 750W" then:

The brand A sells a heavily underpowered motor (300-350 W mechanical), and
The brand B offers a motor with the mechanical peak power greatly exceeding 750 W, being well over 1 kilowatt.

I have never said motors deliver constant torque or power. I only referred to the OP's sentence who was talking about advertised figures.

Please read this in detail. It is how e-bike manufacturers think:

Motors

support.specialized.com

Interestingly, here are the manufacturer data for two motors I have owned:

• Specialized 1.2s: Max power 520 W, max torque 85 Nm
• Giant Syncdrive Pro 2: Max power 520 W, max torque 85 Nm.

These two motors are differently tuned. Giant/Yamaha gives the max torque at the low cadence (MTB), and Specialized/Brose gives high torque at intermediate speed to accelerate to 28 mph quickly (a commuter).

 

[Ravi Kempaiah]

If a brand A says "Our mid-drive motor delivers 50 Nm and has a nominal power of 750W", and
The brand B says "Our mid-drive motor delivers 120 Nm and has a nominal power of 750W" then:

The brand A sells a heavily underpowered motor (300-350 W mechanical), and
The brand B offers a motor with the mechanical peak power greatly exceeding 750 W, being well over 1 kilowatt.

Stefan,
We appreciate your passion for E-bikes, and there is a lot more to Torque ratings than nominal power ratings shared by these E-bike companies.
It is a shame that marketing blurb in the E-bike world can be highly error-prone.
Have a look at this Torque rating for Harley Davidson Live Wire E-motorcycle. This machine produces 75,000 Watts of power and yet rated for ~115 Nm of torque!!

Using the E-bike motor logic you are alluding to, this motor should produce thousands of Nm of torque!! and this is not the case. More over, the problem is exacerbated by motor manufacturers quoting torque at the spindle, not at the rear wheel.

https://www.livewire.com/livewire-one-electric-motorcycle#livewire-pdp-specs

You can check this for yourself. I can give you 100's of examples like this. Torque and power-ratings for E-bikes can be very misleading.
A finely tuned 500W motor/controller can outperform poorly designed 1000W combo.

 

[Gionnirocket]

And yet many continue to...

with Stefan.

 

[Stefan Mikes]

Stefan,
We appreciate your passion for E-bikes, and there is a lot more to Torque ratings than nominal power ratings shared by these E-bike companies.
It is a shame that marketing blurb in the E-bike world can be highly error-prone.
Have a look at this Torque rating for Harley Davidson Live Wire E-motorcycle. This machine produces 75,000 Watts of power and yet rated for ~115 Nm of torque!!

Using the E-bike motor logic you are alluding to, this motor should produce thousands of Nm of torque!! and this is not the case. More over, the problem is exacerbated by motor manufacturers quoting torque at the spindle, not at the rear wheel.

https://www.livewire.com/livewire-one-electric-motorcycle#livewire-pdp-specs

Ravi, I think the angular speed given for the e-motorcycle is related to several thousand rpm? The principal question for a mid-drive e-bike is at which rotating part the rated torque is given by e-bike manufacturers.

You can check this for yourself. I can give you 100's of examples like this. Torque and power-ratings for E-bikes can be very misleading.
A finely tuned 500W motor/controller can outperform poorly designed 1000W combo.

Certainly.

 

[m@Robertson]

The motor you would have in your Zen e-bike is greatly overpowered. While it will simply pull you onto the summit like a lift, I'm sure you will soon learn using far less power on the flat. I do not intend to discuss the differences between Enviolo and Rohloff (all my knowledge about either comes from reading these Fora). I do not, however, think reconfiguring a belt-driven IGH system back to the chain/derailleur is cheap or simple (or even doable).

Its entirely do-able but I can't imagine wanting to do that. Thats like trading a modern car for the one driven by Fred Flintstone. Forget about all the engineering talk. When you get used to a belt that seems to last forever, that never needs maintenance and there is no grease present on your bike, that should end any potential for internal debate. I LOVED my Gates belt'd bike (hated the Shimano IGH) and if it weren't for the insane cost of a Rohloff I would have built bikes only with them once I had that experience under my belt.

My Bullitts can be changed to and from IGH/derailleur via a change in dropouts. And of course different drivetrain parts. And a new rear wheel. The frame break is there from the start so no issue with that. If the bike can be optioned for a derailleur it can be switched back/forth with the only negative being found in your bank balance.

My advice would be Rohloff all the way but the OP has already figured this out. Especially since the motor is an M620 which is running 'only' 120 Nm. Rohloff IIRC has a max of 135 Nm rating and is suited to long slogs rather than short, sharp peaks. Rohloff is also the proven OG of IGH's. Takes a licking and...

 

[Stefan Mikes]

Gentlemen,

Please discuss with these hard numbers.

Specialized and Giant both use the 60 rpm figure to calculate the e-bike motor torque. Then, the marketing department chooses whatever looks better on paper. I am sure Bosch or Fazua or TQ do the same.

Specialized has given 90, 70, and 50 Nm specs for the latest motors made by Brose. As you can see, the less powerful 2.0 and 2.0E motors are actually stronger than advertised. However, put these nice 90, 70 and 50 figures in the advertising material and everyone just dreams of the most expensive motor...

@Ravi Kempaiah: Do you know the actual mechanical peak power of your 120 Nm motor? Please do this simple calculation and tell me what the actual torque at 60 rpm would be. Any idea about the electrical efficiency of that motor, that is, the actual maximum electrical and mechanical power?