Ebike Motor Power Curve Comparison Chart: BOSCH, Yamaha, Shimano, Brose

[motostrano]

Ebike Motor Power Curve Comparison Chart. This test result was leaked recently and has been a topic of conversation in the ebike world for the past few weeks. It shows the power curves of Bosch Performance, Bosch Percormance CX, Shimano, Yamaha and Brose motors.

I was at a dealer event for Moustache ebikes last month in France and this chart was referenced. Good data. I understand it was a leaked chart from one of the motor manufacturers.

Joe

 

[Sonoboy]

While I applaud the fact that we now have comparison data from someone (cough Bosch? cough) it would still be better IMO that a third party could administer tests to ensure a completely unbiased data set. I think that most of us that are well read on this site are not surprised at the results. One still has to consider noise, packaging, initial cost, warranty, etc. but, again, any data on e-bikes these days can be helpful.

 

[Alphbetadog]

I've very surprised by the Brose curve, notably the poor peak performance. I have both a full suspension emtb with the Bosch CX motor and one with the Brose. I actually like the performance of the Brose better. Feels to me like it has as much power, but almost silent. I do tent to ride the Brose in the #2 power setting (out of 3) and rarely change it, whereas with the Bosch I constantly switch between Tour & Turbo modes depending on assistance needed in my effort to extend range. Just got the new emtb update yesterday and haven't been able to try it yet.

 

[pxpaulx]

I've very surprised by the Brose curve, notably the poor peak performance. I have both a full suspension emtb with the Bosch CX motor and one with the Brose. I actually like the performance of the Brose better. Feels to me like it has as much power, but almost silent. I do tent to ride the Brose in the #2 power setting (out of 3) and rarely change it, whereas with the Bosch I constantly switch between Tour & Turbo modes depending on assistance needed in my effort to extend range. Just got the new emtb update yesterday and haven't been able to try it yet.

I'll be curious to see what you think of the new bosch emtb mode. I had my bulls updated in the spring with the latest firmware, I could tell the difference (and a 4th level of assist was also added). I much prefer the Brose power delivery than bosch, it feels like a more natural riding experience. Bosch may provide a little more power, but it also feels slightly detached from the riding experience.

Also agreed with @Sonoboy - it would be much nicer to have an independent testing group. I appreciate that emtb magazine article discussing the strengths and weaknesses of the current mid-drive motors out there, maybe that and actually riding the different motors are really all that is needed!

 

[Alphbetadog]

@pxpaulx; I am planning on taking the bike on some Flagstaff trails tomorrow and really test out the new emtb mode. Unfortunately there isn't a Bulls dealer anywhere in my state to do the Brose update, which I would also like to do. Although both are great, I totally agree with you on the superior riding experience with the Brose as compared to the CX.

 

[motostrano]

While I applaud the fact that we now have comparison data from someone (cough Bosch? cough) it would still be better IMO that a third party could administer tests to ensure a completely unbiased data set. I think that most of us that are well read on this site are not surprised at the results. One still has to consider noise, packaging, initial cost, warranty, etc. but, again, any data on e-bikes these days can be helpful.

I don't know the source of the chart. It could have been independent, so I would not assume out the gate that it wasn't. I'll try to track that down.

 

[emco5]

Motorcycle engines in sport bikes tend to have peaky powerbands. That narrowness of energy creates a ride where you keep the engine revs boiling while you tap the shifter to maintain the rpm. Good fun with a motorcycle on a twisty backroad. Mid-drive PAS eBikes with the same narrow peak power range are not as fun because it’s your legs that keep the crank spinning at the required rpm. As terrain varies, so does your need to spin. Motorcycles best suited to everyday commuting have flatter powerbands. That applies to eBikes, too. A mid-drive that provides a useable level of assist over a wide rpm range is going to be less frenetic. Having a Yamaha or Bosch PL system, as reflected in that chart, would drive me nuts.

 

[Manu]

My surprise is the consumption in watts of certain engines that supposedly are 250w to 350w of shimano and bosh ..... in theory they would now be working above their usual consumption. The one that cuts the revolutions to 100 or 130 is determined By the controller, yamaha I am not surprised the consumption because it has engines 250w to 500w to attend 45km / h.

I think that that excess consumption in the bosh and shimano is given by the size of teeth in the plates and cassette.

I think that maybe having more teeth in a dish gives more range of top speed to less cadence and that helps the engine in more percentage and maximum speed can remove extra charge and therefore consumption in extra watts ....... . In this section the yamaha are leaders because it has option until double plate of 34/44 and 38/48 teeth, the human force accompanies the engine in much more regime of speed and saves watts hours.


Using the GearCalculator app android with wheel 700x40c, cadence of 90 rpm, plate of 48 teeth and cassette of 11 teeth you have a top speed of 52km / h but if you change the plate of 48 teeth for a 22 teeth of bosh the top speed is 23 , 8 km / h, the rest of speed and effort is made by the bosh engine with the consequent higher consumption in peak watts.

 

[Trail Cruiser]

Using the GearCalculator app android with wheel 700x40c, cadence of 90 rpm, plate of 48 teeth and cassette of 11 teeth you have a top speed of 52km / h but if you change the plate of 48 teeth for a 22 teeth of bosh the top speed is 23 , 8 km / h, the rest of speed and effort is made by the bosh engine with the consequent higher consumption in peak watts.

The teeth of the bosch chain ring multiplied by 2.5 is equivalent to the non-bosch chain ring. The 22 teeth is actually the same as the 55 teeth to the non-bosch chain ring. So at 90 rpm cadence, it would be running at 59.6 kph.

 

[Manu]

In the bosh engine the effort developed by human force mechanically gives those 23.8 km / h ..... the rest of the speed that needs to be given in order to reach 40.50,60 km / h is all direct work to the engine , Needs to rotate more turns per second and that is more consumption in watts and more load in mechanical weight for the engine because the human force does not help to take away weight because it does not apply sufficient torque at those speeds ... for this the 550 watts of consumption In the graphic, in the yamaha the engine does not need to rotate to 2 volute per second because the human support is in the speed regime and the human force applies the necessary torque to help the motor and that means much less physical weight to move everything , Less turns, less consumption, same speed

 

[Trail Cruiser]

In the bosh engine the effort developed by human force mechanically gives those 23.8 km / h ..... the rest of the speed that needs to be given in order to reach 40.50,60 km / h is all direct work to the engine , Needs to rotate more turns per second and that is more consumption in watts and more load in mechanical weight for the engine because the human force does not help to take away weight because it does not apply sufficient torque at those speeds ... for this the 550 watts of consumption In the graphic, in the yamaha the engine does not need to rotate to 2 volute per second because the human support is in the speed regime and the human force applies the necessary torque to help the motor and that means much less physical weight to move everything , Less turns, less consumption, same speed

Nice theory, but people who rode and compared different ebikes swears by the the positive characteristics and good qualities of the bosch design.

 

[PaulGee]

I don't know the source of the chart. It could have been independent, so I would not assume out the gate that it wasn't. I'll try to track that down.

I think it is reasonable to assume the source was Bosch since their branding is clearly indicated on the chart while the other motor company trademarks are lacking.

 

[Sonoboy]

Good observation! I was using the fact that both their models peaked above the others.

 

[PaulGee]

Of course lacking details on how the test was performed it is difficult to interpret the data. Still, it is useful information and on a relative basis in line with what I have read about the comparative performance of pre-2017 motor models.

Sonoboy - thanks for sharing!

 

[Alphbetadog]

I'll be curious to see what you think of the new bosch emtb mode.

I took my recently updated Haibike FS CX powered bike and spent most the ride in EMTB mode. I initially really liked it because it made it a little more "intuitive" like my Brose powered Bulls. Was nice just to leave it in "automatic" rather than actively change the power setting depending on the terrain and desired assist. However, like Ravi and maybe others have reported, it does suck the juice much more than my usual changing modes (I previously rode mostly in TOUR, and just occasionally go into TURBO on steep climbs). I found myself 13 miles into the out-and-back ride with only 2 bars left. It was mostly flowy singletrack but with several good serious climbs. Got a little concerned with only having 2 bars left so I put it in ECO for the ride back. Made it with only 1 mile of range left, for a total ride of 22 miles. I have the 400 watt battery. So my takeaway is that emtb is fun, and for casual rides less than 20 miles, or somebody new to emtbs is trying out my bike, but to maximize range I think it is best to manually change modes.

 

[LimboJim]

How does Wattage equate to Torque? It seems to me that the two are not exactly correlated - my 350W, Bosch-equipped Haibike has noticeably less torque than my 250W Yamaha Haibike.

 

[Ravi Kempaiah]

How does Wattage equate to Torque? It seems to me that the two are not exactly correlated - my 350W, Bosch-equipped Haibike has noticeably less torque than my 250W Yamaha Haibike.

I certainly feel that both Yamaha and Brose put out more torque.
I found this chart for the Brose 2018 motor to be interesting.

 

[Trail Cruiser]

I certainly feel that both Yamaha and Brose put out more torque.
I found this chart for the Brose 2018 motor to be interesting.

View attachment 17713

That Brose torque vs rpm graph is very interesting. My calculated guess is that the red curve comes from the new Brose S drive. The peak torque has been expanded about 35% in both the lower and upper RPM range, so if the original upper was in the 80 rpm, the S drive continues to supply 90 NM up to ~108 rpm. That also correspond to 35 percent increase in power from 350 watts to about 475-500 watts. That would put it's performance profile somewhere in between the Bosch and the Shimano Drive.

Yamaha also has it's upgrade, the PW-X, but it looks like Yamaha focused it's performance improvement at the lower end of the rpm range and not much at the upper rpm range. Yamaha's strong point is the zero cadence that applies full torque from a standstill. If abused, it can also overheat the motor.

 

[Trail Cruiser]

Here is another comparison between Bosch CX and the Yamaha PW-X.
(Link Removed - No Longer Exists)

 

[Hugh Jardon]

There is clearly something wrong with the graphs in post#1. The Bosch CX motor outputs zero watts at 120 rpm. The graph shows it as 400W. If you extrapolate the graph forward, it would max out at 160 rpm, when in practice, it maxes out at 120 rpm. Somebody got their data seriously wrong. I don't believe that any of those motors make power past 120 rpm. Only the Yamaha one looks approximately correct.