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The evolution of the torque from e-motors goes up is there generally more efficiency

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    The evolution of the torque from e-motors goes up is there generally more efficiency

    I have just noticed that there is an increase in torque for a bosch mid motor for some makes either later 2020 or for 2021 models.
    The torque has gone up from 50 to 75 NM that seems significant.
    In use and efficiency would this be noticed!

    I would guess for a company like Bosch or Shimano that has more of a reputation than someone like Bafang their biggest issue isn't how much power they can make its how much can they do reliably and staying legal with greatly varying laws in different places.


      Thanks 73Eldo,but to bring out a motor 25N (50 to 75N) in say from a2020 to a 2021 model seems quite a torque increase, thus one assumes a more efficient useful e-motor.
      Or is the torque increase not necessarily more efficiency/ range?


        I don't know for sure. If the case or factor hasn't changed then I would more suspect software changes and creative tech writing of specs to take advantage of gray areas in the laws. More is more betterer in my book so bring it on.


          It could also be increasing the reduction ratio

          Not saying that's what they've done but if you want more torque that's one way of getting there


          • tklop
            tklop commented
            Editing a comment
            That's exactly what I was thinking. Different gearing.

            I'm in a different league--and cannot compare Apples to Oranges.

            So let's consider this a comparison between Apples and Tennis Rackets...

            I'm willing to bet I'm getting both more oomph and higher efficiency than the Bosch has -- out of my 4KW Cyclone -- even though it's also rated for 75Nm.

            (scroll down, bottom row, center motor).


            And for that matter, we could theoretically gear down a drive-motor from a Sony Walkman--to provide 75Nm--but the output-end rotational speed would likely be so slow as to be imperceptible. Forget "Revolutions-Per-Moment" we'd need a measurement for "Revolutions-Per-Month". One might even assert that Walkman motor--so geared--should be adequate enough torque-wise for a e-bike--at least mathematically speaking... Yeah, okay--sure. for the sake of discussion. And for that matter, it's likely a pretty high efficiency-rating could also be attained... But with a top-speed likely less than a couple measly centimeters per hour--good luck maintaining your balance--let alone making it home in time for dinner!

            Anyways. Yeah. Gearing.

            Likely the new version uses a smaller motor with the same wattage-rating, which operates at higher rotational-speeds--and uses a gearbox with a higher reduction-ratio to obtain (roughly) the same output-end rotational-speed as the old version. There's your torque-boost.

            I also wondered if maybe they'd just done a redesign, altering the way their original motor had been wound. Now--I've no idea what either version's engineering is actually like--I just know you get a torque-boost going from say 6T to 12T. But I don't know--I freely admit I'm not totally up to speed in all the subtleties of windings vs. output. Maybe it's possible they've made a combination of changes--both altering the motor's windings, and switching to a higher-gear-ratio reduction gear.


            I have the feeling it's mostly about the gearing.
            Last edited by tklop; 10-15-2020, 12:22 AM.

          Do any of the mid drives use a significantly different gearing scheme? The few I have seen diagrams of seem to be more or less the same. Thinking about it some must be a little different since the noise can be quite different.

          I don't know how well number of poles in a motor scales. If you can make the whole motor bigger then no problem you can do more poles and get a wider range of torque but I think on smaller motors like power tools and E bikes they hit a point where the poles can't be any smaller. Building a motor for a car? There you have a little more room but still I bet a similar issue where they get too small to be able to do the work especially at lower speeds.

          If you want to know about the difference in the gearing just look at cordless tools. Many of those are using the walkman size motors with crazy things like 2000:1 gearbox. Is the average age here old enough that everyone knows what a walkman is and why it would have had a motor? I suppose those that don't are used to and able to instantly look things up.


            I am new to e-bikes, or the idea of one, but as above, physical and " computic" ways to increase torque, even reducing the main motor output sprocket will up torque moment.
            As I am still dithering on which direction to go, I need to know.
            I have seen a new " bargain" ?2020 E-bike with bosch mid motor, some £400 less than the very simmilar 2021 model.
            Only difference is the e-motor info giving 50N for the former and 75N for latter( now boosted to 85N a generic 70% increase)
            I need to work out if I buy a system to self fit or buy new.
            I need lots of i put, so need to FULLY understand what is available to get a direction.
            I like the - batteries in frame trend, BUT fprefer to be able to remove,re-locate as an option to charge.
            Yep a lot o take in
            Last edited by RogerWill; 10-15-2020, 10:00 PM.


              The other thing about the fit in the frame ones is you may be stuck with that specific form factor so there is no easily expanding or replacing it with something different. If it fails you are stuck buying one from that company or maybe finding someone that can rebuild it which isn't always practical with some designs. At least when you buy a DIY kit you know its DIY and there are others coming up with ideas and methods and modifying them. You buy a complete bike you may be getting what you are getting and that's it.


                I think that all that is happening is the manufacturers are playing with the numbers to suit their needs and still fit within the laws. Every e bike law that I've seen lists max watts, max speed, and independent throttles.
                there has to be a +/- factor on watts. And there is the matter of how/when wattage is measured. And just like dieselgate, do consumer models ship with the same programming as test models? I think if the speed is limited then manufacturers will fudge wattage as the top speed is limited yet acceleration rate isn't ever mentioned in e bike laws. For example if the bike is a competitive style mtn bike the torque increase from the higher wattage is more beneficial than the gain but loss of speed with a deeper gear reduction. Especially if the watt limit is 250w. 50w-75w more through a mtn bike cassette is pretty significant in steep terrain.
                I don't think anything they're doing is for better efficiency, they all use programming to accomplish that. Any gains in power in the higher settings such as turbo is for performance only. The big manufacturers like those using Bosch, Shimano, Yamaha, are cycling purists at heart so they are still designing their e bikes to be a bicycle first. They are fine with limiting assist in normal operating mode to stretch battery range. And they have to balance the need to keep the bike street legal or for off road only.
                Last edited by Dshue; 10-17-2020, 10:03 AM.


                  I'm not sure about how enforcement could or does work in other countries but in the USA I just don't see any way they can really enforce or regulate these things because of all those variables and the ease of modifications. I suppose just like cars they can try making the new manufacturers jump through hoops and meet standards that were not created by people that know anything about E bikes but after that all bets are off. Just like a car you can drive it off the lot and modify it or build your own from parts. It will end up being just like cars they will have to have radar guns and clear laws and penalties for going too fast in certain areas.

                  A more interesting question I just thought of is if or when there are more strict laws do or will they apply the same to both E bikes and non E's? There is one fairly long street downhill I ride and drive frequently and I often see people on more road like bikes going over 35 mph there maybe even pushing 40 which is the car speed limit. If there is a E bike limit of 30 can the no E still do 35 or 40? If so why is that OK and the E bike isn't? E bike will do more damage if there is a crash because its a heaver bike with likely a heaver rider but other than that what else is different?


                  • Dshue
                    Dshue commented
                    Editing a comment
                    I have seen that in the UK speed limits don't apply to bicycles. Here i the US I'm sure speed limits are enforced for bicycles in some places. I know the Rails to Trails Conservancy is supportive of ebike use on trails when the e bike is speed limited to 28 mph. They explain that the speed difference is not really an issue as a serious cyclist can ride at a sustained 20mph easily and that cyclist would be sharing the trail with other riders who would ride at much lower sustained speeds less than 10 mph. I know that I've ridden a 30 mile long trail and averaged 8 mph, while a good friend has ridden the same trail and averaged 14 mph.
                    The e bike speed in the US at the federal level is 28 mph and after that the motor is supposed to cut out but you can still pedal faster if you have the gearing. I've gotten the new bike to 38 mph on a small downhill section of road and wasn't really trying, I only saw the max speed after I was home. The tires on this bike actually make the bafang speed correct and assist does cut out at just over 28 mph. The way the US is basing the e bike laws is very similar to the way mo peds(not to be confused with motor scoters)are regulated and they're doing it to keep riders from having to get a license. And as far as I'm concerned e bikes are more about pedaling than mo peds are/were.

                  In the US every state has it's own laws

                  At the federal level the 28mph bikes are not class 1 or 2 and so usually can't go the same places you can go with class 1 or 2 and are limited to streets although national forests presently don't allow even class 1 or 2 on anything not intended for motor vehicles - national parks allow class 1 and 2 but not the faster (20-28mph) bikes where bicycles can go for the most part

                  In AZ at the state level class 1 or 2 (750W/20mph without or with throttle) = bicycle and can go anywhere a bicycle can go which includes anywhere a pedestrian can go (this includes sidewalks) - local municipalities can have their own limitations but very few do... Tempe does however - most likely due to the presence of the huge university


                    People tell me all the time I have no class...... but if I did I think it would have to be:



                    • Dshue
                      Dshue commented
                      Editing a comment
                      That is the classification sticker I want for my bike. Except maybe the class can be upped to 11, most will get the 1.21GW 88mph reference but only the true pop culture nerds will understand why it goes to 11.
                      Last edited by Dshue; 10-19-2020, 08:15 AM.

                    • 73Eldo
                      73Eldo commented
                      Editing a comment
                      Its like how much more black could this be? And the answer is none, none more black.

                      I also really like when they are lost in the basement and keep running into the janitor on the way to the stage, 'hello Cleveland' was it?

                      No one a big enough nerd to connect my avatar to the sticker either?

                    Originally posted by 73Eldo View Post
                    People tell me all the time I have no class...... but if I did I think it would have to be:

                    Is that for ebikes with a flux capacitor? Click image for larger version

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                    • 73Eldo
                      73Eldo commented
                      Editing a comment
                      I don't know that I need a flux capacitor but Mr Fusion would be nice for charging on the go.