Best Mid-drive Motors in 2021

Discussions related to motors other than hub motors.
This includes R/C motors, botttom bracket, roller and geared drives.
azad   10 W

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Best Mid-drive Motors in 2021

Post by azad » Apr 25 2021 3:31am

Hi,

I know there are many kits and motors out there but what I would like to know is the state-of-art only in 2021. More specifically, I would like to know the best motors in the range 1.5kw - 5kw with high efficiency, endurance and silence. I know Bafang motors and I very much like them specially BBSHD or Bafang Ultra but they are limited in average speed (<50 km/h) and Bafang Ultra can not be easily mounted as well. Is there any other motor that could beat them or are we at the edge of technology?

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Re: Best Mid-drive Motors in 2021

Post by DingusMcGee » Apr 25 2021 5:25am

We embed technology .........the edge is in your mind.

Kits? Do you mean plug and play kits? Kits are products that repeat/propagate the same bad designs.

Bafang -- there is plenty of testimony here along the lines of how do I fix my Bafang such & such...

"State of the art".... Read these threads. You add the art....

Start with a bare motor

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Re: Best Mid-drive Motors in 2021

Post by azad » Apr 26 2021 11:59am

DingusMcGee wrote:
Apr 25 2021 5:25am
We embed technology .........the edge is in your mind.

Kits? Do you mean plug and play kits? Kits are products that repeat/propagate the same bad designs.

Bafang -- there is plenty of testimony here along the lines of how do I fix my Bafang such & such...

"State of the art".... Read these threads. You add the art....

Start with a bare motor
I did start with a motor. And it was hell to repair and maintain continuously (chains/sprockets etc), for years, until I moved to bagang which is bottom bracket mounted and is reliable. I have done more than 2200kms and it has stood the test.

Just creating art is not enough. We need real engineering in order to take on the challenges of life!

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Re: Best Mid-drive Motors in 2021

Post by DingusMcGee » Apr 26 2021 12:46pm

Azad,

You ask for the state-of-the-art and now you are telling me 'we [you?] need real engineering....'

Specialized Bikes makes an engineered ebike -- no kit, no he'll to repair. Service at your local dealer. You might have to get one with two motors if you want a motor wattage >1.5kw

You might build a bike frame with 3 bottom bracket shells so you could install 3 bagang mid drive motors and I bet you can get speeds >50 km/hr. The product would be both engineered and state of the art. I have yet to see a three motored ebike. Start with 3 bare motors. Preferably, 3 different makers and wattages? I would put the three throttles on the right.

If you chose a triple rather than a tandem you would not have to weld -in any BB shells.

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Re: Best Mid-drive Motors in 2021

Post by ferret » Apr 27 2021 1:17am

DingusMcGee wrote:
Apr 26 2021 12:46pm
...
I have yet to see a three motored ebike. Start with 3 bare motors. Preferably, 3 different makers and wattages? I would put the three throttles on the right.

If you chose a triple rather than a tandem you would not have to weld -in any BB shells.
viewtopic.php?f=28&t=74176

Image
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Re: Best Mid-drive Motors in 2021

Post by 2old » Apr 27 2021 11:32am

Easiest solution might be an M1Sportechnik ($10,000 or so) which can achieve 45 mph pretty easily AFAIK.

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Re: Best Mid-drive Motors in 2021

Post by Compoundbike » Apr 27 2021 1:48pm

CYC X1 Pro has a torque-sensing and has more power then a bafang.

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Re: Best Mid-drive Motors in 2021

Post by azad » Apr 30 2021 11:58am

Compoundbike wrote:
Apr 27 2021 1:48pm
CYC X1 Pro has a torque-sensing and has more power then a bafang.
It doesn't seem to have a gear box. Wonder how it would fare uphill. Also I notice a chain drive, these kinds are noisy and chain derailing can happen as well. I had a similar setup in the past it was very painful.

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Re: Best Mid-drive Motors in 2021

Post by azad » Apr 30 2021 11:59am

2old wrote:
Apr 27 2021 11:32am
Easiest solution might be an M1Sportechnik ($10,000 or so) which can achieve 45 mph pretty easily AFAIK.
I thought it was a DIY forum :) Ofcourse ebikes might be out there but I am trying to build my own and not too expensive either!

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Re: Best Mid-drive Motors in 2021

Post by azad » Apr 30 2021 12:00pm

ferret wrote:
Apr 27 2021 1:17am
DingusMcGee wrote:
Apr 26 2021 12:46pm
...
I have yet to see a three motored ebike. Start with 3 bare motors. Preferably, 3 different makers and wattages? I would put the three throttles on the right.

If you chose a triple rather than a tandem you would not have to weld -in any BB shells.
viewtopic.php?f=28&t=74176

Image

This looks nice. What frame do you think it is enduro or stealth bomber? Also are these 775 motors?

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Re: Best Mid-drive Motors in 2021

Post by Grantmac » Apr 30 2021 10:24pm

azad wrote:
Apr 30 2021 11:58am
Compoundbike wrote:
Apr 27 2021 1:48pm
CYC X1 Pro has a torque-sensing and has more power then a bafang.
It doesn't seem to have a gear box. Wonder how it would fare uphill. Also I notice a chain drive, these kinds are noisy and chain derailing can happen as well. I had a similar setup in the past it was very painful.
And serious off-roading a Bafang will break the bottom bracket, pick your poison.

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Re: Best Mid-drive Motors in 2021

Post by azad » May 01 2021 11:29am

DingusMcGee wrote:
Apr 26 2021 12:46pm
Azad,

You ask for the state-of-the-art and now you are telling me 'we [you?] need real engineering....'

Specialized Bikes makes an engineered ebike -- no kit, no he'll to repair. Service at your local dealer. You might have to get one with two motors if you want a motor wattage >1.5kw

You might build a bike frame with 3 bottom bracket shells so you could install 3 bagang mid drive motors and I bet you can get speeds >50 km/hr. The product would be both engineered and state of the art. I have yet to see a three motored ebike. Start with 3 bare motors. Preferably, 3 different makers and wattages? I would put the three throttles on the right.

If you chose a triple rather than a tandem you would not have to weld -in any BB shells.
I hope you weren't joking. Three motors means three times more power requirement, different manufacturer means different efficiency and torque. Three throttles? seriously?!
Now that would be utterly an art but not engineering!

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Re: Best Mid-drive Motors in 2021

Post by DingusMcGee » May 02 2021 8:34pm

azad,

You have stressed efficiency for the motor. Why not also get a bike type that rolls efficiently to have an overall low energy consumption? A hard tail carbon fiber framed racing bike employing titanium components and very high pressure tires with those aero rims would get you more miles per kw.

You hint a need for high motor efficiency. Well, sad story is that all these electro repulsion/attraction motors are only 50% efficient at maximum power -- Thevinnans Equivalent Circuit for electric Motors. Yet you seem willing to settle for a measure of the manufacturers stated efficiency at some ONE high rpm spot where the motor produces little power- - - Engineering nonsense.

If you are going to engineer a motor-to-bike fit for high efficiency, you will need a power spectrum data set of the load demand you specifically will be using the on the ebike to assist you matched to your motor choices for each motor's power spectrum efficiency to find the least energy consumption for your use. It is a simple job for a computer nerd but you need an accurate data set of the motors efficiency and power/torque at each increment of rpm.

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Re: Best Mid-drive Motors in 2021

Post by Deafcat » Jun 26 2021 1:17am

Hey guys,

I've got a new mid-drive motor you'll like:

  • it's more powerful than a Bafang Ultra
  • it uses a high resolution torque+cadence PAS
  • it's made in Canada (mostly)
  • it took me a whole year to design
  • it does not rely on wimpy bicycle chain, but it still pedals like any bicycle, with up to 12 speeds
  • it's compatible with fat tires, 29+, all that jazz
  • it does 40 MPH without breaking a sweat, and can climb and tow like a champ
  • it can do all of this with fairly conventional batteries (typically 52V 40A 900-1100Wh)
  • the drivetrain service interval is over 5,000km
what could it be :?:

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Re: Best Mid-drive Motors in 2021

Post by Grantmac » Jun 26 2021 11:32am

Deafcat wrote:
Jun 26 2021 1:17am
Hey guys,

I've got a new mid-drive motor you'll like:

  • it's more powerful than a Bafang Ultra
  • it uses a high resolution torque+cadence PAS
  • it's made in Canada (mostly)
  • it took me a whole year to design
  • it does not rely on wimpy bicycle chain, but it still pedals like any bicycle, with up to 12 speeds
  • it's compatible with fat tires, 29+, all that jazz
  • it does 40 MPH without breaking a sweat, and can climb and tow like a champ
  • it can do all of this with fairly conventional batteries (typically 52V 40A 900-1100Wh)
  • the drivetrain service interval is over 5,000km
what could it be :?:
How much does it weigh and can it be retrofit?

I'm in Canada and depending on those questions I'd be an early adopter.

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Re: Best Mid-drive Motors in 2021

Post by TNC » Jun 26 2021 11:42am

Grantmac wrote:
Apr 30 2021 10:24pm
azad wrote:
Apr 30 2021 11:58am
Compoundbike wrote:
Apr 27 2021 1:48pm
CYC X1 Pro has a torque-sensing and has more power then a bafang.
It doesn't seem to have a gear box. Wonder how it would fare uphill. Also I notice a chain drive, these kinds are noisy and chain derailing can happen as well. I had a similar setup in the past it was very painful.
And serious off-roading a Bafang will break the bottom bracket, pick your poison.
Grant, there's a lot of "depends" in that statement...and I don't mean the kind in demand down at the old folks home. :lol:

But seriously, we've had a little of this discussion before. I guess the subjective description of what "serious off-roading" is can fog up the lens of opinion here. On the extreme end of "serious off-roading", like hucking the bike from decent drops, slamming into ledge climbs, and clearing a 20' gap at speed, I'd agree that a mid-drive, home install is not the best or correct choice for that application. But this "serious off-roading" doesn't just apply to that level only. Riding fast in tight terrain...riding over semi-small rock gardens...getting a little air over smaller drops and rises...these are not going to destroy the motor or the bike as long as the bike was already capable of this type of riding to begin with. And let's be honest...this is what and how most mountain bikers ride in probably 90% of the cases.

The slightly lower ground clearance of a Bafang mid-drive...and probably most mid-drives...is probably the biggest limiting factor for really gnarly off road. Even at that my current SC Nomad with a BBSHD is basically the same clearance as the Trek Rail 7 emtb demo bike we have at the shop. There is no question that I could ride my Nomad at Moab on most all the "biggies" like Porcupine, etc. and do just fine. Better line choice and the occasional "get-off-and-lift" would be the only requirement, and I contend that it wouldn't be that frequent where I'd have to dismount anymore than I would have on my pedal-only Nomad. There are a few places on Porc that I have to do that anyway since I'm not Hans Rey.

Your comment on "breaking the bottom bracket" is interesting. While I would agree that nothing made by man is impossible to break on "serious off-road"...even a KTM 500...maybe the type of bicycle being converted is the issue. Sticking a BBSHD on an XC MTB is probably not a good idea if harder core riding is in the mix. However, sticking that motor into a burly Enduro/AM or DH level frame is a better idea. I'll add to that the issue that most of the Bafang mid-drive applications are going into older MTB's that may not be in head-to-head competition with the latest and greatest new MTB's out there. Only an idiot would buy a new top tier, big hit, long travel, well equipped MTB and install a mid-drive. At that point one is much better served getting a Trek Rail, Spec Levo, new gen SC Bullit, or even a Luna X1 or such. If the BB on my '09 Nomad eventually gets "hogged-out" or worn or even "breaks"...well...it served its purpose, and I doubt that will happen tomorrow. Grant, I would like to know some detail as how you determine the BB will fail...actual crack in the frame shell, hogged out threads in the shell, egg-shaping the shell over time. or what. I won't argue that it is possible for any of these to occur over time, but I think a lot of that depends on the frame we're talking about and yes...the type of riding. In response to the concern of the BBSHD "moving" or dropping down while in use, I just made a simple aluminum plate to add a little more support to the motor.

If I were young and still sending it with some truly, gnarly, hardcore freeride applications, I would buy the new Santa Cruz Bullit emtb. However, a solid bike like my older Nomad with a BBSHD will allow some very decent mountain biking without breaking the bank and breaking the frame the first time out.

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Re: Best Mid-drive Motors in 2021

Post by Grantmac » Jun 26 2021 2:46pm

I'm not talking about frame breakage, I mean the BB on the motor. Specifically the small bearings and square taper cranks.

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Re: Best Mid-drive Motors in 2021

Post by Deafcat » Jun 26 2021 4:34pm

Grantmac wrote:
Jun 26 2021 11:32am
Deafcat wrote:
Jun 26 2021 1:17am
Hey guys,

I've got a new mid-drive motor you'll like:

  • it's more powerful than a Bafang Ultra
  • it uses a high resolution torque+cadence PAS
  • it's made in Canada (mostly)
  • it took me a whole year to design
  • it does not rely on wimpy bicycle chain, but it still pedals like any bicycle, with up to 12 speeds
  • it's compatible with fat tires, 29+, all that jazz
  • it does 40 MPH without breaking a sweat, and can climb and tow like a champ
  • it can do all of this with fairly conventional batteries (typically 52V 40A 900-1100Wh)
  • the drivetrain service interval is over 5,000km
what could it be :?:
How much does it weigh and can it be retrofit?

I'm in Canada and depending on those questions I'd be an early adopter.
Weight is comparable with Bafang Ultra, and only looking to sell it on complete bikes this year. More news to come very soon, should be able to share complete details by Canada Day. Building 3 dozen bikes as a pilot batch, hoping to sell most of those in SK and BC (my home provinces). Cheers!

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Re: Best Mid-drive Motors in 2021

Post by TNC » Jun 26 2021 4:37pm

Grantmac wrote:
Jun 26 2021 2:46pm
I'm not talking about frame breakage, I mean the BB on the motor. Specifically the small bearings and square taper cranks.
Yeah, going back to square taper cranks kind of concerned me, but I thought back to my days of the more freeride oriented riding. My '99 Bullit had square taper, but I eventually put a Monster T and the longer shock that you could install on the Bullit for more travel. I beat the tar out of that bike with jumps and drops...never broke or wallowed out a crank arm. I did use quality crank arms of the day, but still, no issue. And don't get me wrong...I would never claim them for the hardcore riding these days, but they miraculously survived a lot of gnarly riding back in the day. I don't do that level of stuff now even though my trail riding is still relatively aggressive. I no longer look for places like Bartlett Wash at Moab to do the Toilet Bowl or other hardcore playground style features, but I still like to rip rough, challenging trail.

On on those square taper cranks, my concern was enough to cause me to just pick up a BMX crankset through the shop that is way better made than the Bafang units. It is a Promax and they are stout. They are straight arms like the Bafangs and they're shorter at 165mm. I learned how good the aluminum in them was yesterday when cutting off the chainring spider and bench grinding the excess material off on the drive side arm. I expected easy work on the bench grinder with a good stone, but it was a bit of work. I thought about getting two non-drive arms and retapping the pedal threads in one with our shop tool and inserting a helicoil with red stud mount loctite for the drive side. Instead I just worked on the drive side arm, and it worked out perfectly.

Grant, you mention "small bearings" in the motor BB. Can you elaborate on that? I'm going to install the heavier duty gear in the BBSHD that's often recommended. I haven't seen or read common issues with the BB bearings. I've seen the exploded parts view of the motor with the spindle and bearings, and they appear to be a serviceable item. But I'm not up on servicing the BBSHD down to that level, so I'd like to hear any input on that.

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Re: Best Mid-drive Motors in 2021

Post by Deafcat » Jun 26 2021 4:46pm

Grantmac wrote:
Jun 26 2021 2:46pm
I'm not talking about frame breakage, I mean the BB on the motor. Specifically the small bearings and square taper cranks.
Interesting this topic should come up as well: We've been beating up this new motor of ours on hard+fast trail riding, even crash testing it, as the most common extraneous issues for a motor system (outside of the core motor guts reliability) is damage to cranks, spindle, bottom bracket failure... Usually resulting from harsh pedal strikes on trail obstructions, or wipe-outs.

What I've found is that "bigger" crank interfaces like ISIS usually are super robust, but complicate aftermarket compatibilities... Bafang for example even went ahead and switched away from ISIS to a proprietary crank interface on M600, thereby eliminating aftermarket options (such as cranks from Miranda etc). Generally considered a bad move.

However, with square taper spindles, the cranks may get bent, but easily replaced with huge range of options. If the spindle/bottom bracket fails, it's usually on account of narrow profile bearings, poor quality/worn bearings, or a poorly made spindle with weak alloy.

Preferred solution: Make a square taper spindle out of very robust alloy (Niagara-Lasalle Fatigue-Proof 125ksi+, or equivalent), and use very good quality, very wide bearings with careful consideration of how the forces are transferred from the bearings, into the motor/structural assembly.

This is precisely the solution I'm using in our motor.


TNC wrote:
Jun 26 2021 4:37pm
On on those square taper cranks, my concern was enough to cause me to just pick up a BMX crankset through the shop that is way better made than the Bafang units. It is a Promax and they are stout. They are straight arms like the Bafangs and they're shorter at 165mm.
Shorter cranks are a great choice! I've run as short as 150mm on some of my bikes, currently sourcing these from Miranda and Box Components (Box 5 BMX). Origin8 also has some suitable offerings here. I haven't used Promax for short cranks yet but have used their regular cranks... Do you have a link/model for those?

Some big perks to shorter cranks: better ground clearance, less leverage in a strike/crash resulting in less damage, less pedal travel is more comfortable at higher cadences, trying to keep up with fast bike without resorting to oversize chainring (which are not smart on rough trail/mtb courses, but a great choice for road).

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Re: Best Mid-drive Motors in 2021

Post by HK12K » Jun 26 2021 5:45pm

Lightingrods.

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Re: Best Mid-drive Motors in 2021

Post by Grantmac » Jun 26 2021 7:35pm

It's possible that because you aren't having to stand on the pedals that the BBSHD bottom bracket will stand up well. I guess the same could be said for square taper cranks.

Still definitely not what I'm after.

Deafcat,

What total bike weight are you going for? Sounds like some sort of gearbox system....I'm interested.

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Re: Best Mid-drive Motors in 2021

Post by Deafcat » Jun 26 2021 10:21pm

Grantmac wrote:
Jun 26 2021 7:35pm
What total bike weight are you going for? Sounds like some sort of gearbox system....I'm interested.
Around 30 kg for the whole bike, depending on wheel/tire and battery config. As low as 25kg is easy achievable with carbon fork/bars and good wheels, I built a custom Ultra bike not long ago with such a config.

No gearbox, besides a quiet planetary gearset..

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Re: Best Mid-drive Motors in 2021

Post by TNC » Jun 26 2021 10:59pm

Deafcat, I work at a shop, and I got them through QBP which is a big, dealer wholesale place. They are Promax SQ-1. However, those cranksets are readily available on ebay and elsewhere. They've been around for awhile are quite proven. They are a relative bargain for their quality. They are made in Taiwan also instead of mainland China.

I will also add that I mispoke on the length of my Promax crankarms. I always use 165mm cranks on my big hit MTB's for the usual, obvious reasons. For this BBSHD setup I went to 160mm crankarms since the motor has a ton of torque, and I just don't need longer arms.

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Post by Deafcat » Jun 27 2021 2:04am

TNC wrote:
Jun 26 2021 10:59pm
Deafcat, I work at a shop, and I got them through QBP which is a big, dealer wholesale place. They are Promax SQ-1. However, those cranksets are readily available on ebay and elsewhere. They've been around for awhile are quite proven. They are a relative bargain for their quality. They are made in Taiwan also instead of mainland China.

I will also add that I mispoke on the length of my Promax crankarms. I always use 165mm cranks on my big hit MTB's for the usual, obvious reasons. For this BBSHD setup I went to 160mm crankarms since the motor has a ton of torque, and I just don't need longer arms.
Heheh, QBP is actually much bigger than a dealer/wholesaler :D

those SQ-1 look like a solid option, Cheers!

Edit: here's the Box cranks I'm currently testing: https://boxcomponents.com/collections/c ... -cranksets

They are similar style and basically identical weight per size compared with the Promax. Both the Box and SQ-1 I think look better and are probably stronger than the Origin8 option (though, the O8 cranks have the ability to mount chainring in or outside of flange, for more chain line adjustment).

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