What do you think is the best mini-hub motor?

[ebike4healthandfitness]

For the purposes of this thread we will define mini-hub motor as any motor where the front version weighs 2.1 kg or less.

 

[offGridDownUnder]

If you have a folding bike, the front fork is often only 75mm wide. In that case the Crystalite SAW20 may be the only option. It is direct drive (DD - no gears) and it exceeds your weight limit, but again, that 75mm OLD dimension.

 

[ebike4healthandfitness]

If you have a folding bike, the front fork is often only 75mm wide. In that case the Crystalite SAW20 may be the only option. It is direct drive (DD - no gears) and it exceeds your weight limit, but again, that 75mm OLD dimension.

This motor has 75mm OLD and weighs 1.6kg:

AKM85SX(F1)_Aikema Electric Drive System (Suzhou) Co., Ltd_Motors_Batteries

AKM85SX(F1)-Aikema Electric Drive System (Suzhou) Co., Ltd_Motors_Batteries-Rated Power: 250W<br> Max Torque: 30N.m<br> Weight: 1.6kg

www.aikema-e.com

 

[hillslayer@]

For the purposes of this thread we will define mini-hub motor as any motor where the front version weighs 2.1 kg or less.

 

[lnanek]

Didn't follow the link, eh?

AKM85SX(F1)
Rated Power: 250W
Max Torque: 30N.m
Weight: 1.6kg

 

[molybdenum]

The Q100c might be worth mentioning; at 2.1kg, 350W, rear CST, and 135mm dropouts, it will fit a standard hybrid/mtb frame. Although I have never tried the Q100c, some others here have used it to good effect, and it might be the next motor I try for an extreme lean but mean build. I have been using the larger Q128c (500W) version since 2017 for a daily 30km round trip and it has lasted me forever and been problem-free in a hilly and very wet region.

Q100C CST 36V350W Rear Driving EBike Hub Motor RPM 328

Q100C CST 36V350W Rear Driving V-brake, rim-brake, Disc-Brake compatible E-Bike Hub Motor.

bmsbattery.com

 

[bikes4two]

For an OLN of 100mm there's two more to think about: the Aikema 100SX (2.1kg) and the Bafang G370 (1.7kg)

 

[docw009]

Have three folders with 135mm Q100H motors in the rear wheel, although these bikes had 100mm front wheels. I did put a 100mm Q100H into the front wheel of my minivello. That makes four Q100H that I own, and I like the motor a lot.

 

[ebike4healthandfitness]

The Q100c might be worth mentioning; at 2.1kg, 350W, rear CST, and 135mm dropouts, it will fit a standard hybrid/mtb frame. Although I have never tried the Q100c, some others here have used it to good effect, and it might be the next motor I try for an extreme lean but mean build. I have been using the larger Q128c (500W) version since 2017 for a daily 30km round trip and it has lasted me forever and been problem-free in a hilly and very wet region.

Q100C CST 36V350W Rear Driving EBike Hub Motor RPM 328

Q100C CST 36V350W Rear Driving V-brake, rim-brake, Disc-Brake compatible E-Bike Hub Motor.

bmsbattery.com

The Q100C is unique among Q100 variants in that it is the only one (according to the thread I am linking below) to to use .35mm laminations:

Q100 and Q128 with 0.35mm laminations

580 watts for 30mph is maybe what you see when you're going downhill a bit.. that's more of the type of wattage figure you'd see for 25mph btw. 10w doesn't seem like much. I bet that the losses amplify with wattage applied? I'm no motor design expert though.. Good point. I can maintain around...

endless-sphere.com

Currently, the Q100 CST shipping from BMSB already has 0.35 laminations. This is also why it's such a good performer even though the motor is tiny.

These improved laminations were given it appears to compensate for the fact motor has a narrower stator than the non cassette Q100 variants:

Q100 and Q128 with 0.35mm laminations

Problems is a general term, so here you are ... In regards to hub motors being less problematic than the other drive systems, I agree , in fact that is why I am so much interested in improvements on hub motors, and am going to buy another hub motor and ... not buy the BBS02 . The the...

endless-sphere.com

To make room for the cassette, the CST uses a stator about 2/3's the width of the standard Q100 and consequently produces the least amount of power. Approx. 2/3rd.'s of the H and 3/4th.'s of the standard.

 

[ebike4healthandfitness]

For an OLN of 100mm there's two more to think about: the Aikema 100SX (2.1kg) and the Bafang G370 (1.7kg)

From a wheel build standpoint this version of the Aikema 100SX linked below (which is dish-less with 47mm spacing between center of spoke flanges) is much better than the Bafang G370 (second image below) which has 4.5mm dishing offset and spoke flange spacing of 45mm (measured from center of flange to center of flange):

AKM100SX(F1)_Aikema Electric Drive System (Suzhou) Co., Ltd_Motors_Batteries

AKM100SX(F1)-Aikema Electric Drive System (Suzhou) Co., Ltd_Motors_Batteries-Rated Power: 250W<br> Max Torque: 45N.m<br> Weight: 1.9kg

www.aikema-e.com

Bafang G370F (measurements from ebikes.ca spoke calculator):



Why is this important? Because there isn't much difference in weight between motors and it is easier to build a laterally stiff and durable wheel with lighter components using the Aikema hubshell.

 

[neptronix]

Big problem i have with these small hubs is poor efficiency.
G370 maxes out at 82.5% efficiency on the ebikes.ca motor simulator.
Q100H delivers a sad 81.5% on their dyno.

Keyde claim 88-90% efficiency for their tiny motors. They range from 1.6 to 2.1kg and 300-500w peak. This is with a controller inside the motor also, so the hub motor is thermally choked by that controller's additional heat. Given that, they are probably capable of more power than rated with the controller ripped out.

( there seems to be an adequate amount of cable exiting the motor to run some wimpy 20ga wires and hall wires )



But i'm skeptical of these efficiency claims and never seen a dyno to back up this exceedingly high efficiency.

I tried a Xiongda YTW-06 ( 1.4kg ) a long time ago. The build quality on two motors was trash and it had an insane amount of drag. I suggest pre-emptively crossing that one off your list.