Enviolo or Rohloff?

[Cybersnow]

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.

 

[Bicyclista]

My experience with an Enviolo hub on a Tern HSD S+ was that it was not as efficient as casette gears nor would it shift at the right moment. I know you wanted a comparison between Enviolo and Rohloff, but don't forget regular gears if you want the most efficient transfer of power for climbing.

 

[Stefan Mikes]

I am looking at a line of mid drive motors that increase my torque from 85Nm to 120Nm for the same wattage.

Does anyone else see a flaw in the reasoning here?

 

[Cybersnow]

Being a retired engineer, i called the engineering group at both facilities. The Enviolo folks basically said that it was primarily an urban hub that performed well in flat and rolling hills. The Rohloff folks explained their hub was made especially for e-bikes that needed to pull long steep hills. I also checked with two of my favorite bike shops who had experience in the kinds of riding we still do and they recommended the Rohloff. So I just ordered a Zen Photon Ultra with the Bafang M620 motor and the Rohloff hub.

 

[Cybersnow]

Does anyone else see a flaw in the reasoning here?

I would be interested in your thoughts

 

[Stefan Mikes]

Being a retired engineer

...you should be aware the Torque = Power / Rotational (angular) speed (rad/s). The rotational (angular) speed at the chainring remains the same in the same gear and at the same e-bike speed with the same wheel size. If one e-bike mid-drive motor can deliver 85 Nm and another 120 Nm, it simply means the max motor power for either is dramatically different.

 

[Cybersnow]

Translated into two identical bikes riding up the same hill ridden by the same rider and one bike is a 750w 50Nm motor and the other is a 750W 120Nm motor, would the ride up be different? While my leg power is not calibrated I can say that the second bike was easier to ride and was significantly faster In the same set of gear ratios.

 

[Stefan Mikes]

Translated into two identical bikes riding up the same hill ridden by the same rider and one bike is a 750w 50Nm motor and the other is a 750W 120Nm motor, would the ride up be different? While my leg power is not calibrated I can say that the second bike was easier to ride and was significantly faster In the same set of gear ratios.

It is impossible one 750 W mid-drive motor could have 50 Nm and another 750 W one would have 120 Nm.

Often, a manufacturer gives the electrical power of the motor because it is a higher figure and it looks good on paper. Assuming the motor efficiency is 75%, the max mechanical power delivered by such a motor would be around 560 W, and it usually translates to 85-90 Nm of torque. I assume the max mechanical power of a 120 Nm mid-drive motor could approach mechanically some 800 W, which could translate to over 1 kW electrical wattage, and it is a highly probable number for a strong motor.

Of course, a more powerful motor would climb steep hills far easier than the weaker one. Now, we also talk about the gearing (Enviolo, Rohloff or derailleur). IGHs have far worse efficiency than the chain/derailleur, eating good Watts off your motor. (The gearing itself is basically the speed you can achieve on the climbing at given rotational speed of your crank as you pedal, or cadence). The 120 Nm motor you are talking about is as powerful you would not expect any difficulty to climb the steepest hills, at the cost of a significant battery charge use.

 

[Cybersnow]

I agree with most of what you say. Unfortunately at 78, I wanted a step through bike. I didnt find one with a more powerful motor that didnt come with belt drive and some sort of hub. So I had the option really of Enviolo or Rohloff. I just bought the Rohloff bike after a long conversation with a technical person at Enviolo. If that doesn't work, I will have the wheel rebuilt or replaced and go to a chain and deraileur set up.

I realize there are some outstanding Bosch powered bikes out there, but they were out of my budget.

 

[Tom@WashDC]

Being a retired engineer, i called the engineering group at both facilities. The Enviolo folks basically said that it was primarily an urban hub that performed well in flat and rolling hills. The Rohloff folks explained their hub was made especially for e-bikes that needed to pull long steep hills. I also checked with two of my favorite bike shops who had experience in the kinds of riding we still do and they recommended the Rohloff. So I just ordered a Zen Photon Ultra with the Bafang M620 motor and the Rohloff hub.

You are going to love the Ultra/Rohloff combo. What size rear sprocket and front chain ring will it have?
See my Rohloff Speedhub installation thread.

 

[Cybersnow]

No idea, it is a belt driven set up. Zen Photon Ultra.

 

[AvalancheRun]

Rohloff 100%

Far more gearing. I find the Enviolo 380% lacks low gearing for steep climbs which means very slow cadence.
Digital control is far easier than the twist control.
Adjustable downshift at stops.
More efficient.

 

[Cybersnow]

Zen Photon Ultra is outfitted with a Rohloff driven by a Bafang M620

 

[Gionnirocket]

No idea, it is a belt driven set up. Zen Photon Ultra.

If my bike is any indication it'll be in the ballpark of a 40t x 17t. Do belt cogs cross reference?
I find the bottom 5 gears almost impossible to use in most cases as down to 6 it's already a climbing beast. I never enjoyed pedaling like a drowning rat to achieve 6mph no matter the climb.
One possible use may be with motor failure and I've got hills between me and home. At some point I do plan on changing the chain ring to 42t - 44t the latter being my first choice.

Good luck with the new bike.

 

[scrambler]

It is impossible one 750 W mid-drive motor could have 50 Nm and another 750 W one would have 120 Nm.

I am not sure this is quite correct. I believe the Torque formula includes rpm, and rpm can vary depending on the amps / volt relationship.
Torque = Power x constant / rpm
Constant = 5252
So with more rpm (speed) comes less torque and vice versa
So with the same power (Volt x amps), you can have one configured to use more volts and less Amps, and the other to use less volts and more amps.
The first one will have less Torque and more speed, and the second one will have more torque and less speed.

I will need to do some digging to get the physics detail confirmation

 

[scrambler]

To comment on the OP question, the Rohloff will have a larger gear range. This means that is your usage condition span across a larger range, like steep hills at one end and fast speed at the other, the Rohloff will better cover that range.

If on the other hand you need very low gearing for steep hills, but don't care too much about speed, or need speed, but don't do extreme climbing, then the Enviolo limited range can be adjusted to your need by changing the rear / front sprocket ratio.

Another factor is if you are addicted to gear change or prefer smoother more automatic gearing. Rohloff will give you more traditional control over gear change, while Enviolo will simplify it. This is very subjective, and not as critical on an electric bike, where there is no real need for 14 gear levels.

 

[Cybersnow]

I am sure I will love the ultra, but if i end up hating the Rohloff , i will drop back to a chain Sram 500% system an reconfigure the m620 to off road.

 

[gromike]

If the motor has enough power then it can substitute for lower gearing. My bbs02 goes up steep, admittedly short slopes on throttle only, geared 42/32, if I so desired, drawing 1200w +. You don't need a whole bunch of gears on a mid-drive. If it can output enough power, and you can pedal it at your top speed. On the other hand, I have taken a fondness to riding at the lowest assist level. Now I'm using all of its 8 gears. On my similarly powered dd hubdrive bike I need all of its 24 gears. If you plan to do technical, best to go 250w with some nice and low gears. That's a whole other animal.

 

[Stefan Mikes]

I am not sure this is quite correct. I believe the Torque formula includes rpm, and rpm can vary depending on the amps / volt relationship.
Torque = Power x constant / rpm
Constant = 5252
So with more rpm (speed) comes less torque and vice versa

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.

 

[Stefan Mikes]

I am sure I will love the ultra, but if i end up hating the Rohloff , i will drop back to a chain Sram 500% system an reconfigure the m620 to off road.

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).