Best Sub 4KG hub motor ?

qwerkus

10 kW
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Jul 22, 2017
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Title sums it up: what's the most powerfull hub motor under 4KG currently available - APART FROM THE XIONGDA 2 SPEED ? That one does not fit into my aluminium (disc only) frame.
 
"Best" for what?

Hills, Flats, Stop & Go, Drag Racing, Groceries, Going Up Steep Ski Slopes, Slalom Racing, Single Track, Pathways ?
 
You can’t expect much power from a 3kg motor. The ability of a motor to stand being fed high Amperage does rely on copper mass of the coil, and its ability to shed the heat is also proportional to its size and weight.

The future will bring us small motors that will be capable of better performance, with liquid cooling, improved magnetic properties, and lighter materials. Today, weight is pretty much the essential factor of performance.
 
A couple of years ago I searched for a 3 kg or under powerful motor , but could not find any. I have two 2.1 kg motors that are not powerful and a Mac motor that is just over 4 kg that has a decent amount of power but not as much as the DD hubs that are 2x or more its weight, and it does not have enough power to get me up steep hills (Road ) fast enough.
So
I have given up on searching , hub motors are low power or mid power, or if they can put out a good amount of power they are very heavy and then you need a heavier frame, forks, wheels, more batteries which in turn are now heavier, and it goes on and on ,the bike keeps getting heavier and heavier .

I am now waiting for more development progress with RC motors designed to work on bicycles. RC motors are up to 1kg or 1.5 kg for a heavy one , and now with the new 12 speed drivetrains ( Sram Eagle NX ), and now a new 9 speed e-bike drivetrain ( Box Components ) , with up to a 50 tooth cog on the rear , we will have reduction ratio's that are good enough for many of us.
and some of the newer motors have a lower KV, RC Motors are becoming more viable as a bicycle motor.
 
ScooterMan101 said:
...RC Motors are becoming more viable as a bicycle motor.
Yep, RC motors are in a faster evolution than hub notors. Yet they are small and low power. They can compete with success against BB drives and small hubs. But when it comes to high speed and hard acceleration, they are very far from the big hubs that are available now, even if they are old technology. Many of them are capable 200 Nm and can speed well above 70 Mph, no gear shifting required. No RC mid drive build can come close

The problem with small mid drives is the drivetrain. You need a motorcycle drivetrain to compete with big DD hubs. Then you can beat them, but the weight saving is long gone.
 
I think this is much better than the Xiongda
https://bmsbattery.com/ebike-kit/775-q128h-36v800w-rear-driving-ebike-hub-motor-ebike-kit.html
 
ScooterMan101 said:
I am now waiting for more development progress with RC motors designed to work on bicycles. RC motors are up to 1kg or 1.5 kg for a heavy one , and now with the new 12 speed drivetrains ( Sram Eagle NX ), and now a new 9 speed e-bike drivetrain ( Box Components ) , with up to a 50 tooth cog on the rear , we will have reduction ratio's that are good enough for many of us.
and some of the newer motors have a lower KV, RC Motors are becoming more viable as a bicycle motor.

When using RC motors you should be aware that most power specs like continuous power or current ratings are pulled from the air, and don't expect too much peak power as a small and lightweigt motor will overheat much quicker as a larger one.
If you you go this route then it is important to have the right gearing (reduction) and properly control of motor current. Then there is a good chance that such drive will work very well.

The best 4kg geared hubmotor probably is the MAC, and if it should be a direct dirve then it's the BionX D-series (but needs to be converted) or the Grin Tech all axle motor.
 
Thank you all for your answers - although it a quite disappointing picture. I understand more and more why grin tech is developping their own DD motor. Having tried both, I'm more an more convinced by the low maintenance nature of hub motors. Just fixed an old 24V heinzmann motor a couple of weeks ago, which was built in 1997 - and still runing!

I'm not into speed, so what I'm looking for are cargo helper with a top speed of 30-40 km/h. I saw the mac, though it looks heavy.

Otherwise only alternatives I found are shengyi:
http://www.syimotor.com/productDe_47.html
http://www.syimotor.com/productDe_3.html

Next size would be the aotema DD drive:
https://www.aotema.com/index.php?main_page=product_info&cPath=2&products_id=79&zenid=1ce9af44cda31ee7c37f1279eee2995b

Around 5Kg. They seem to have come up with a second version. Not sure what it's worth.
 
Not hub motors, but neither were rc motors or mid drives....... right

https://alienpowersystem.com/product-category/brushless-motors/
4kg - 120100 motor - 25,000W - https://alienpowersystem.com/shop/brushless-motors/120100-w-outrunner-brushless-motor-50kv-25000w-water-cooled/

3.2kg - 15070 motor - 30,000W - https://alienpowersystem.com/shop/brushless-motors/15070s-sensored-outrunner-brushless-motor-35kv-30000w-paramotor/

I've been temtped to buy one or an Astro motor and build something. I prefer silence while riding, rc motor + mid drive = I can't imagine what the birds and deer would think to themselves as I ride by.

Friction Drive from their motor
https://endless-sphere.com/forums/viewtopic.php?f=28&t=90970&p=1396238&hilit=alienpowersystem#p1325868

Some random comment about a 6kw WEIGHT (g): 1.250 alienpowersystem
https://endless-sphere.com/forums/viewtopic.php?f=3&t=90432&p=1369200&hilit=alienpowersystem#p1369200
running on 6374 3200W Alien motor and is a real joy to ride.








No worries, I am glad I can help out. Time to soak it all in before the white stuff falls and e-cruise anywhere but here!

Chow!
 
Thank you all for your answers - although it's a quite disappointing picture. I understand more and more why grin tech is developing their own DD motor. Having tried both, I'm more an more convinced by the low maintenance nature of hub motors for commuters. Just fixed a bike with an old 24V heinzmann motor a couple of weeks ago, which was built in 1997 - and still running!

I'm not into speed, so what I'm looking for are cargo helper with a top speed of 30-40 km/h. I saw the mac, though it looks heavy.

Otherwise only alternatives I found are shengyi:
http://www.syimotor.com/productDe_47.html
http://www.syimotor.com/productDe_3.html

Next size would be the aotema DD drive:
https://www.aotema.com/index.php?main_page=product_info&cPath=2&products_id=79&zenid=1ce9af44cda31ee7c37f1279eee2995b

Around 5Kg. They seem to have come up with a second version. Not sure what it's worth.
 
If going for a really light setup, that would mean you'd have to carry the bike up stairs for example, or you need a light nimble setup for slalom turns. The only way to increase power and have even weight is then have a front motor and a rear motor, but you have to see what the benefits are against a motor of equal weight to both those f & r motors.
 
Not a chance. One big motor that weights the same as 2 small ones, will always be capable of more power and making a better ride.

The only advantage of 2wd on a bike, is slow riding on loose terrain.
 
ScooterMan101 said:
A couple of years ago I searched for a 3 kg or under powerful motor , but could not find any. I have two 2.1 kg motors that are not powerful and a Mac motor that is just over 4 kg that has a decent amount of power but not as much as the DD hubs that are 2x or more its weight, and it does not have enough power to get me up steep hills (Road ) fast enough.

You might want to consider a 20" wheel build if you want very high power density.
Even a modern mid/low grade 1000w rated DD motor with 0.35mm laminations will produce over 100ft-lb of torque, and cruise at 85% efficiency on the right setup. Sustained 40mph cruising speeds are very possible.

A MAC, driven with a very high RPM rated controller, will climb a wall on 20" wheels and >= 72v.. the only problem is that it will scream like a banshee unless said controller is a FOC/sine driver..

Unfortunately you're probably out of luck with the 20" wheel hack on the dual reduction motors, because the kind of controller that could handle >80,000 eRPM is in unobtanium / ungodly expensive / shitty RC controller territory.
 
MadRhino said:
Not a chance. One big motor that weights the same as 2 small ones, will always be capable of more power and making a better ride.

The only advantage of 2wd on a bike, is slow riding on loose terrain.

I think it would not be a bad idea to use two small (2-3kg) geared hubmotors instead of one.

Have you ever ridden a 2WD bike with two MAC motors? The acceleration is insane! With only 3kW of total input power that bike was much quicker off the line up to 30-40kmh as one large Hubmotor (mxus 3k or Cromotor) with more than twice the input power.

the pros of 2WD:

very high efficiency under load
better weight distribution (suspension response etc)
better cooling

the cons of 2WD:

higher costs and more hassle with the wiring (two controllers)
higher no load losses, or more consumption when cruising at moderate speeds on the flat (-> it would make sense to switch off one motor to gain efficiency)
 
madin88 said:
Have you ever ridden a 2WD bike with two MAC motors? The acceleration is insane! With only 3kW of total input power that bike was much quicker off the line up to 30-40kmh as one large Hubmotor (mxus 3k or Cromotor) with more than twice the input power.
...

Yep, but you can feed a cromotor 25kw in acceleration. If you’d try, you opinion might change about how much acceleration is ‘insane’. :twisted:

A geared hub is not for hard riding. It doesn’t like to hit, hate to be lifted off the ground, and very long to shed the heat.
 
Neptronix,

Well I am making do with my Mac 6T motor in a 27.5 wheel until a good RC mid-drive ( that is affordable ) becomes available.
The only two things my 6T Mac will not do is climb up steep hills that are over 6% grade that are also over a half mile or so long, and go more than about 30-32 mph ( I am using 2x7s battery packs for 58 volts at up to 30 amps.
I would like to make it go a little faster and have bought a 72 volt controller up to 30 amps from Em3ev.com ... https://em3ev.com/shop/9-fet-irfb4110-infineon-controller/
And would like to experiment with that controller and a 16s battery pack
and/or 3x 6s packs for a 18s pack, or take 3 of my 7s packs for operating it at 21s , keeping it mostly running on level ground .

How will the Mac perform with either a 16s pack or a 18s , or even 3x 7s for a 21s pack ? ( 16s/18s/21s for days of flat ground long distance runs )

Keep in mind that for hills I am waiting on getting a RC Mid-Drive system.
I have limited funds so will not re-lace the Mac onto a small wheel, I like it the way it is , just would like some more speed from it for covering long distances.
I must save up for one of the newer generation RC mid-drive systems . I will keep the Mac powered bike for mostly flat and back roads , and build up my full suspension bike with the mid-drive.





neptronix said:
ScooterMan101 said:
A couple of years ago I searched for a 3 kg or under powerful motor , but could not find any. I have two 2.1 kg motors that are not powerful and a Mac motor that is just over 4 kg that has a decent amount of power but not as much as the DD hubs that are 2x or more its weight, and it does not have enough power to get me up steep hills (Road ) fast enough.

You might want to consider a 20" wheel build if you want very high power density.
Even a modern mid/low grade 1000w rated DD motor with 0.35mm laminations will produce over 100ft-lb of torque, and cruise at 85% efficiency on the right setup. Sustained 40mph cruising speeds are very possible.

A MAC, driven with a very high RPM rated controller, will climb a wall on 20" wheels and >= 72v.. the only problem is that it will scream like a banshee unless said controller is a FOC/sine driver..

Unfortunately you're probably out of luck with the 20" wheel hack on the dual reduction motors, because the kind of controller that could handle >80,000 eRPM is in unobtanium / ungodly expensive / shitty RC controller territory.
 
That 6T needs more amps.. not more volts. ( see an ebikes.ca simulator and you'll see what i mean. ) That 6T would be nice at 40 amps or above.

A dual reduction motor can be basically like having an RC drive in your wheel.. these things spin at 3,000-5,000 rpm and have hall sensors available, so you can use more reliable, less expensive controllers than say, castle creations units you'd be stuck with on a RC motor.

( or go with a small wheel and increase your power density and actually run 72v on that MAC - it will go like a scalded cat.. )
 
neptronix said:
That 6T needs more amps.. not more volts. ( see an ebikes.ca simulator and you'll see what i mean. ) That 6T would be nice at 40 amps or above.

A dual reduction motor can be basically like having an RC drive in your wheel.. these things spin at 3,000-5,000 rpm and have hall sensors available, so you can use more reliable, less expensive controllers than say, castle creations units you'd be stuck with on a RC motor.

( or go with a small wheel and increase your power density and actually run 72v on that MAC - it will go like a scalded cat.. )

That's a good point. The gears are probably capable of handling the same amount of absolute torque, so you could dump twice the amps into a 6T and get it to produce the same torque as a 12T. The losses are proportional to I^2 * R, but the R is lower with the fast 6T wind... So, I don't know how exactly it would balance out. My guess is if you just use the higher current to accelerate, it would be fine.

The motor is probably also rated for some average wattage regardless of the wind, so as long as it doesn't overheat, it should be fine. The 6T would be nice with high amps to accelerate and low voltage to cruise at high speeds (52v?).

But, I am wondering if the 6T would overheat while cruising at max speed (38 mph) anyway?

Would a 8T be better in a 26" wheel, if you can't really use the top speed without overheating?
 
n2mb said:
But, I am wondering if the 6T would overheat while cruising at max speed (38 mph) anyway?

Would a 8T be better in a 26" wheel, if you can't really use the top speed without overheating?

Watts are watts.
A 12T and a 6T will produce roughly the same amount of waste heat at a 2000W continuous load. ( +/- 2% )
So maybe the 12T needs 100V and 20A whereas the 6T needs 50V and 40A.

38 mph comes out to around 2000 watts on a motor like a MAC. The motor is rated conservatively at 1000W but may be capable of more like 1500W continuous. No matter what winding or voltage/amperage, the motor just can't do 2000W continuously, until you put it in a 20" wheel, which greatly increases the continuous power handling and torque output of the motor..

Don't believe me? play with the ebikes.ca simulator for a while.
I've ran high amp, low voltage motors.. and high voltage, low amp motors of the same kinds and not noticed a difference between the types.
In fact, the most efficient hub motor i've ever seen just absolutely loved doing 40mph on 48v and an 80A peak current limit.. it would draw ~40A cruising.. no problem!

8T is better in a 26" wheel if your battery voltage is too high and your cruise speed is far beyond what the motor can push continuously.. yes.
 
Its good to see the Mac motor now represented on Grin's Simulator ! ( it was not there last time I looked )

From what little I understand for my weight, little to no leg watt power, the 6T in a 27.5 wheel works good at 52volts at 35 amps at or near 100% throttle, Looks Iike I will keep the 48volt 40 amp controller on the bike and save the 72volt 30 amp controller for another project. I have 12s packs for times of going up hills , and could buy some 5s packs ( x2) in the future to play around with 42 volts at 40 amps.

Who makes Dual Reduction Motors ? Who sells them ?

( in case the GNG Pro X1 winds up being too expensive . Any new word on it ?
I did not want to bump its thread which is now a little over a month old, it is now within the time frame they said it should be ready ? )




neptronix said:
That 6T needs more amps.. not more volts. ( see an ebikes.ca simulator and you'll see what i mean. ) That 6T would be nice at 40 amps or above.

A dual reduction motor can be basically like having an RC drive in your wheel.. these things spin at 3,000-5,000 rpm and have hall sensors available, so you can use more reliable, less expensive controllers than say, castle creations units you'd be stuck with on a RC motor.

( or go with a small wheel and increase your power density and actually run 72v on that MAC - it will go like a scalded cat.. )
 
It's been on there for while. Before, you could have substituted with the BMC motor.

Dual reduction motors are made by a few companies. Bafang makes the G310 ( rumor is 750w continuous on that ).. Xiongda is selling a ~3lb 350w capable YTW-06. and then other companies like outrider and keyde are selling shades in between.

There's no big dual reduction motor out there unfortunately. MAC is still the king of geared motors.
 
Which motor is that ?

It's weight ?

DD hub ?

Who sells it ?

It is going to need some serious Heavy Duty Batteries , I do have a couple of ( 4 ) ,
7s cells that fit that description. But un sprung hub weight is a concern of mine .

If too heavy then Back to finding out what the GNG Pro X1 is capable of running at in terms of volts and amps ??


neptronix said:
I've ran high amp, low voltage motors.. and high voltage, low amp motors of the same kinds and not noticed a difference between the types.
In fact, the most efficient hub motor i've ever seen just absolutely loved doing 40mph on 48v and an 80A peak current limit.. it would draw ~40A cruising.. no problem!
 
The next motor I will spend money on will have to do much better than my current Mac, both in terms of volts and amps.

neptronix said:
It's been on there for while. Before, you could have substituted with the BMC motor.

Dual reduction motors are made by a few companies. Bafang makes the G310 ( rumor is 750w continuous on that ).. Xiongda is selling a ~3lb 350w capable YTW-06. and then other companies like outrider and keyde are selling shades in between.

There's no big dual reduction motor out there unfortunately. MAC is still the king of geared motors.
 
I'm referring to the 16lb. leafmotor 1500w.. which.. realistically.. i found is capable of 2000w continuous.
That thing loved amps. And the 91% efficiency peak was a real thing.

For the power it put out, it was light.. but it's still a DD so still a boat anchor.. :)

GNG Pro X1 is one of the few things that excites me these days. No idea on what i can handle, but for sure it is going to require an exotic controller and thus only the cool kids will be tuning it.. :D
 
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