Featured Torque curves - Shimano, Bosch, Brose, Yamaha

[100 Cols]

Car manufacturers have shown torque and power curves across the rev range for decades. That seems to have stood the test of time.

I always understood that the power shown was the continuous power available at the rpm shown, not the peak power.

But of course the big difference is that the power unit there is an internal combustion engine and not a battery, which is a markedly different power source. So what does Tesla do?

AFAIK, the power and torque charts have always shown maximum power (a.k.a peak power). It's something that an engine can output a brief period of time, but no one expects that you can drive a car "flat out" days on end (like "continuously") - and still keep regular service periods etc.

The definition of the legislative "250W continuous power" is one of the great mysteries of our times. I have searched through the whole world wide web without founding any valid technical specification for it. The Illuminati must have hidden the original copy and now reveals it only for the chosen ones.

 

[MikeDee]

Isn't power really limited by how many volts x amps the controller puts out rather than the motor?

As a roadie that averages about 85 rpm cadence (maybe 10 rpm less on the mountain bike), the Yamaha motor wouldn't work for me. I think it's a bit ridiculous how "peaky" that motor is.

 

[steve_sordy]

On test rides, I didn't get on with the Yamaha motor. I found that it was pulsing and I could feel it through my feet. The Giant rep said that I wasn't pedalling fast enough! I was trying to ride normally, changing gear to keep in my usual cadence range.

 

[fos'l]

Guess I'm too insensitive to recognize the problem, but I've had a 2017 Haibike SDURO, hardtail with Yamaha motor, for a couple of years and it works well for me.

 

[b45her]

the graph pretty much lines up with what my arse tells me when riding the various different motors, and i beleive my own arse before any company's wild claims.

 

[stiv674]

On test rides, I didn't get on with the Yamaha motor. I found that it was pulsing and I could feel it through my feet. The Giant rep said that I wasn't pedalling fast enough! I was trying to ride normally, changing gear to keep in my usual cadence range.

Agree with that.

I tried two Giant Yamaha bikes but didn't like the over eagerness of the motor, I could imagine it's good on climbs when you need an instant burst of power but it didn't feel natural to me, which the Shimano seems to do a lot better.

 

[sendler2112]

This is not Shimano related post, but couldn't find a better place for posting, so here we go.

I found power curves of few motors from the electricbikereview.com and did some "reverse engineering" to visualize also the torque curves (something I've not seen before). I was interested in torque, because when climbing, torque is usually more relevant than max power and also because I was frustrated of reading manufacturer torque claims without any reference to corresponding crank rpm.

Some of you might be interested in this, too:

View attachment 1352

The original power chart looks like this:
View attachment 1356

Flame on.

I can tell you that the the power chart that is posted is incorrect regarding the Brose as would be in a Specialized. I have an early 2017 Hardtail with the Brose and also a 2018 Haibike with the Yamaha PW and there is nowhere in the rev range that the Yamaha is noticeably stronger. The Yamaha actually does show the predicted roll off of power above 90 rpm. The newer PW-X2 would be better. The Specialized continues to make good power all the way up to as fast as I can spin my legs. 120-130 rpm. RobRides did a good video with a drag race hill climb of the 4 newest versions of these motors and the results were Bosch 19.78 seconds, Specialized Brose 20.32, Yamaha PW-X2 21.07, and Shimano EP8 a distant 23.31 After the first run showed an early roll off of power in higher (normal all out) cadence and clocked in at a very disappointing 26.76 so he did it again with a lower cadence. He does go on to say later that the Shimano has a very natural feel to the torque sensing so I am still considering buying a new E8000 bike with external battery since I never use my Specialized on the highest setting which makes it a little too jumpy to control in tight trails if it is muddy anyway.
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[Kernow]

Been deciding which motor to buy next recently , it seems as big a choice as the bike ,
Robs hill climb test was a very good indeed I thought thanks Rob
then I watched this And saw that most of the best hill climb results in competitions went to bosch as well

 

[lightning]

Well, the video features Tracey Moseley who is sponsored by Bosch, so it's hardly likely she's going to recommend you get a Yamaha Shimano etc

But there's no denying Bosch Ebike motors are up there with the best.

 

[steve_sordy]

I can tell you that the the power chart that is posted is incorrect regarding the Brose as would be in a Specialized. I have an early 2017 Hardtail with the Brose and also a 2018 Haibike with the Yamaha PW and there is nowhere in the rev range that the Yamaha is noticeably stronger. The Yamaha actually does show the predicted roll off of power above 90 rpm. The newer PW-X2 would be better. The Specialized continues to make good power all the way up to as fast as I can spin my legs. 120-130 rpm. RobRides did a good video with a drag race hill climb of the 4 newest versions of these motors and the results were Bosch 19.78 seconds, Specialized Brose 20.32, Yamaha PW-X2 21.07, and Shimano EP8 a distant 23.31 After the first run showed an early roll off of power in higher (normal all out) cadence and clocked in at a very disappointing 26.76 so he did it again with a lower cadence. He does go on to say later that the Shimano has a very natural feel to the torque sensing so I am still considering buying a new E8000 bike with external battery since I never use my Specialized on the highest setting which makes it a little too jumpy to control in tight trails if it is muddy anyway.
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Does anyone know what bike that was with the Bosch gen4 motor?

 

[Kernow]

Well, the video features Tracey Moseley who is sponsored by Bosch, so it's hardly likely she's going to recommend you get a Yamaha Shimano etc

But there's no denying Bosch Ebike motors are up there with the best.

I think it was the embn guy commented that the majority of the wins taken on the climbing events were bikes with bosch motors . mosely will indorse trek as a brand more than just the motor

 

[rhyko7]

Would like to see more of these tests: different RPM's in different modes compared between different bikes. I ride a Trek rail & find the power output in various modes completely out of sync with my friends specialized. E.G the specialized levo gives way more output in eco