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bosch mid drive vs hub motor

Old 01-09-16, 12:06 AM
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bosch mid drive vs hub motor

I have heard from an ebike enthusiast that the hub motor is inherently less efficient than a mid drive motor. we're talking maybe 10 more lbs on the hub motor, with 1/2 the range (which bewilders me because I didn't know that electric motors could have a <50% efficiency; maybe it was a battery issue). anyhow, I have not ridden e bikes extensively enough to verify this; I only work on them. But I'm curious what people think.. To me, it's obvious that if there's any loss of efficiency in the hub motor, it is in the electric motor itself, and not in the arrangement of the drive train. I want to know why the mid drive is "more efficient" than a hub motor.

Anyone here have the knowledge I'm looking for?

here's a video of a hub motor opened up.

Last edited by spectastic; 01-09-16 at 12:11 AM.
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Old 01-09-16, 10:45 AM
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I think most of the discussion about "efficiency" is not about the electrical characteristics, but about the fact that a mid-drive delivers its power thru the existing drive-train (gears, derailleur, internal hub) just as is done when pedaling. A hub motor does not take advantage of any existing drive-train components. There are lots of discussions about the differences/pros and cons between the 2 on the web. Here's just 2 of them:
Electric Bike Motor Comparison: Hub, Mid Drive, & Friction Drive | Electric Bike Report | Electric Bike, Ebikes, Electric Bicycles, E Bike, Reviews

Advantages of Electric Bike Mid-Drive Motor Vs. Hub Motor
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Old 01-09-16, 10:47 AM
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Yep, mid-drive uses the "gearing" of the bike, while hub motors don't.
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Old 01-09-16, 02:00 PM
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thanks for the article.

ok.. so the gearing in the bike allows the motor to maintain a low gear ratio on the climbs, while the hub motor does not? yea I guess that makes sense..
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Old 01-09-16, 04:37 PM
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The only drawback is the need to learn how to shift gears correctly with a mid drive. A NuVinci hub solves that problem, as it is a perfect (but, from experience, darn HEAVY) pairing for a mid drive system. No gears to strip.
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Old 01-09-16, 07:54 PM
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Originally Posted by tds101
The only drawback is the need to learn how to shift gears correctly with a mid drive. A NuVinci hub solves that problem, as it is a perfect (but, from experience, darn HEAVY) pairing for a mid drive system. No gears to strip.
there's a wrong way to shift?
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Old 01-09-16, 08:25 PM
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Watch a few of Court's mid drive/ebike reviews on electricbikereview.com and you'll get an in-depth idea of what I mean.
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Old 01-09-16, 08:52 PM
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FWIW, I just touch my brake lever to "kill" the engine prior to shifting on my BBS02 and haven't had a problem. What I can't understand is that as much as I like the mid-drive, I grab my cheap rear hub motor bike most of the time.
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Old 01-09-16, 10:28 PM
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it happens to me too. I've only used my nice road bike to race like twice last season, out of fear that I might damage my nice bike.


so it's not a good idea to shift under load in a mid drive motor. that's a simple fix... don't shift under load. or as mentioned, tap one of the brakes to kill the motor. treat it like a car with stick shift.
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Old 01-09-16, 11:16 PM
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One last thing; you don't really need to shift frequently, from my experience, since the motor provides a lot of assistance.
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Old 01-10-16, 09:17 AM
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FWIW I shift my BaFang BBS02 350W/36V mid-drive all the time just like a non-electric bike. I do nothing different; no tapping of the brake. Over 200 miles so far with no issues. Hopefully over 220 miles after today's ride

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Old 01-10-16, 09:30 AM
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I would choose BOSH mid drive instead cheap primitive hub kit of course.
AND
I would choose quality hub edrive over cheap mid drive.
With mid drive you work with gears a lot , it is important what gear are you in.
I tried Optibike and to reach speeds and climbs I had to use gears MUCH more often than on my DD hubs.
With DD hub /throttle only/ you basically dont care what gear you are in.
On my DD hubs with throttles I use only 2 gears , mostly 11-tooth out of 7-gear cassette.
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Old 01-10-16, 10:38 AM
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Hub motors dont put out much torque, OK if its Flat & going faster is the goal.

My Local Shop has mid drive conversions, screws in where the BB goes.

MTB Elk hunters and fat bikes as beach buggys are the users. (around here)

Bosch type mid drives need be part of a new Bike since the frame is made around the drive.


Raleigh sells a $3K bike like that

Efficiency testing parameters are something you may be able to do,

in Engineering Labs at the University level ..

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Old 01-10-16, 04:39 PM
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Orbea is coming out with a 24" wheel Bosch mid-drive. I think around $2,500.
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Old 01-10-16, 04:56 PM
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If you want more torque from a hub motor it's easy, just get a bigger one...
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Old 01-11-16, 07:16 PM
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For my next bike set up I was actually starting to consider a mid drive but... I never thought of shifting, and the difficulties I may encounter with a mid drive as I never had to even consider what happens may happen, when I shift my bike with a hub motor... Nothing, that's what. I shift like I was riding a normal bike. Same with the PAS, My set up senses the pressure on the pedals and gives me whatever % I choose to add to my pedaling effort... Maybe the solution for me is just to get a more powerful hub motor, who cares about the gearing with a more powerful hub motor for the hills... What do you people think?
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Old 01-11-16, 07:34 PM
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I think (IMHO) you should forget the Bionix system, buy a hub motor with an external controller, connect a 3000 watt controller to it, at least double the capacity of your current battery pack and then you won't worry about which gear you're in. The big advantage to hub motors is that they are (generally) ultra reliable with almost no maintenance. If you're going off road the torque and weight reduction benefits of the mid drive are obvious but it comes with a much higher maintenance and time/cost over the life of the system. For general on-road use it's hard to beat the simplicity of a hub motor. You can always buy a 500 watt sticker from Holmes Hobbies, no one will know the difference.
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Old 01-11-16, 07:42 PM
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Originally Posted by OCDesigns
I think (IMHO) you should forget the Bionix system, buy a hub motor with an external controller, connect a 3000 watt controller to it, at least double the capacity of your current battery pack and then you won't worry about which gear you're in. The big advantage to hub motors is that they are (generally) ultra reliable with almost no maintenance. If you're going off road the torque and weight reduction benefits of the mid drive are obvious but it comes with a much higher maintenance and time/cost over the life of the system. For general on-road use it's hard to beat the simplicity of a hub motor. You can always buy a 500 watt sticker from Holmes Hobbies, no one will know the difference.

WOW, That's almost exactly what I was thinking/debating with myself... Who really needs the complexities of a hub drive system when all you need is a bit bigger motor/battery... The "problem" is, I do want, prefer, like, and think proportional assist is the way I want to go...
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Old 01-11-16, 11:39 PM
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agree with OCD (probably have it too) that for street use a hub is optimal, but mid for off road if that's in the equation.
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