Electric Dual HUB Motor Disassembly & Performance

Hi Folks.

Today I am going to reveal a small insight to the HUB motor I have on hand at the moment. I have this set of Hub motor for a while and I have them opened for inspection. This is a Chinese made Hub motor, possibly the best I could found out there. As you might be familiar to the look, yes this comes from lofty ambition.

Since I am so curious about HUB motor, I decided to buy 1 that is already finished. Note: this is probably not the best Hub motor out there as they are Humie and Carvon and others. However I weight only 60kg’s and The Netherlands big cities have no hills to climb. Nevertheless I need hub motor that is completely sealed due to the constant rainy weather in The Netherlands. In short this Hub motor fits my budget and condition, so I decided to get them and test them.

Note: The cover have been painted in black since I don’t like the shiny things over my build and the bolts have been replaced with an anti-rust bolts.

Below are some of the photos

My Thoughts:

  1. In overall quite well build, however it’s not recommended for people who consider them self heavy as the hub motors sits on a small rectangular spot on the truck to counter the rotational force of the hub motor as well as to keep them aligned with the ground.
  2. It doesn’t get hot spinning full speed without load on 6s, however it could get pretty hot with serious load, speed and distance / hills.
  3. They are weather sealed good for rainy weather and lower maintenance, however heat could be a problem for some.
  4. The urethane are replaceable, I have some spare which is nice!
  5. They are 90mm in size, quite large and could definitely handle some obstacles.
  6. They are equipped with hall sensor (you can see it from the photos), which is good to help starting from static.
  7. They are very quite running on RC grade ESC compared to my satellite configuration. I wonder how silent it would be with VESC FOC mode.
  8. Not bad for the price. 350 euro with all of the cost of tax and cosmetic upgrade I did.

Here is a video

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Nice… looks exactly like jacob’s design but a diff config.

and it has 24 what do you call them ? stators ? usually i see only 12 .
and sensored ? those making their own hub motors and bldc motors should step up their game and post sales on ebay and alibaba .

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What weight would you consider to be the safe max? 150?

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@mostwanted Yea I think it have 24 stator, if I am not mistaken what stator means (normally stator is situated at the outside ring, but because this is outrunner it could be in the inside). Not quite sure why this Hub motor have 24 instead of 12 like what you think. Not sure what are the implications, but logically it should be smoother with higher torque.

Well I didn’t build this Hub motor, I bought them. Off course when ordered alot it could be rebranded and modified to further improved the design. To be honest there are things that could be improved within this Hub motor, but it requires me to order like between 20 - 100 of them. PS I also don’t like the colors :smiley:

@barajabali Not quite sure what weight it could handle, I haven’t even mount this yet on my board. From my bench test I could see the potential of carrying my weight. I could safely say it have more power than single belt driven 190kv motor. The torque on Hub motor would be less than belt drive, however most people on hub motor here will be running dual Hub motor. Starting torque should not be an issue, also especially with the added Hall sensors. I have to say the torque of brushless outrunner are relative to the speed they are rotating. They are designed to run on certain rpm to be able to output their maximum torque. So climbing hills slowly seems not to be an option for these motors.

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Oh okay thank you for the great reveiw! Sometimes the Internet (alibaba) has some gems

Maybe can put some silicone at the edge of the hub cover then turn it to a real waterproof weapon? :scream:

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@Evan yes that is definitely a good idea. Today I just did a soak test, there are traces of water within the lip of the cover. However it didn’t get into the hub yet. Nevertheless there aren’t things that could be damaged badly from a brushless outrunner even placed under water (besides the hall sensor).

One thing to add. It seems that these bearings are not easy to replace or even unreplaceable. So the entire cover of the bearing and the plate have to be replaced. That doesn’t seems to be a a real big issue after all. The only 2 things I don’t really like from this Hub motor are the wobble and the heat that could build up.

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Bearings should be pull out easily if you’ve got / made a proper tool… Trust me, China staff won’t be that complex, as simple as possible is good to everyone lol.

OH I see the axle is just a bolt? You can even change that to a single theard in order to make it stronger… Should reduce some uneven shaking?!

Thanks for showing. The stator has 24 teeth. Nice for torque.

I wonder how many volts you could do with the vesc though as so many teeth will increase the commutation speed necessary per rotation. Maybe. Not a typical 12x14 pole motor

If the bearings are a slide fit and not a press fit Id get some “retaining fluid” and make them solid especially if the shaft is aluminum.

Is the shaft the bearing sits on steel or aluminum? Looks like steel. Maybe heavy but good thing to have.

What wobbles? The motor or the motor on truck square? I’d put retaining fluid on every interface.

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To be honest I don’t know about the bearings sittings, wether they are glued welded and or fitting fit. However the connections have to be pretty strong as they have to handle torsional load from our weight, cruising vibration, hitting obstacle and or other thing that would make it come loose.

@evan Yes the axle is only a long bolt, with about 1 cm insertion to the truck axle. This is the weakest point of this hub motor as I could see it. If I mount both bolt without the hub motor, I could see that they are slightly bend to the side of the road. However if the hub motor is installed, those flat spot with the rectangular joint from the truck axle and the hub motor makes the mounting of the hub motor feels more horizontal again, only small wobble occurred which I don’t think within 6s configuration is a problem.

@hummie I believe the metal piece of the bearings are aluminium (based on color and temperature), although most skate bearings I have were steel covered. The metal plate that holds the bearing are pretty thick (if you see the photos I have above). The other weak point of this hub motor is that both cover plates of the hub motor are being hold by 12 small 2.5mm hex bolts that are only 6mm in length. Yes they are short and very hard to be thighten and they will need to withstand all of the load. So not tightening this properly will cause the hub motor to be rotating in an awkward direction. Could cause stress to the motor on high speed and load. As far as I could sense from my bench test, one side of my hub motor that are more wobbly gets slightly hotter than the other side. Yes I would put retaining fluid everywhere when I have test this hub motor with my build so I know where are the stress points.

Once u put retaining fluid on it makes the bearing as hard to remove as a press fit so be careful.

I’m a bit confused by your answer …are the bearings resting on steel on their inner and outer surfaces or aluminum? The plates and the shaft.

@evan I dont think this Hub motor could be fitted into a standard longboard axle. Although the hub motor have big holes to fit the entire wheels to a longboard axle, the nuts that holds the motor / wheels wouldn’t be able to handle the torsional load given by the hub. Thats the reason why small rectangular flat spot exist there. I also dream of the same thing, it would be nice to have hub motor that could easily fit into standard caliber 2 trucks by extending the back metal part of the hub motor to fit into the D shaped hanger to counter the torsional load. I believe this will add cost to the production, but definitely achievable.

What other thing I noticed is that these hub motor are 5.5cm in width. It’s 0.5cm wider than standard 90mm longboard wheels which is around 4.5cm to 5cm. So in case the additional metal could be added to fit into the D shaped hanger to counter the torsional load, the nuts have to placed / lock deeper inside the hub motor as the axle of standard caliber 2 trucks are shorter compared to the length of the bolt used by this Hub motor.

Well I don’t think this is a big issue in the end, as a matter all of the hub motor being sold or created nowdays also being sold with the truck axle as well. What is more important in this construction is that the Chinese factory have to use larger bolt size, making sure they are aligned perfectly when the hub are mounted with the truck axle, uses longer M2.5 hex bolt (instead of 6mm use 1cm or longer), better urethane that have perfectly rounded shape.

I believe wobble is always something which very hard to encounter on hub motor. The metal part could be perfectly round, but the urethane could have different softness on certain spot especially they are quite thin compared to a standard round 90mm longboard wheels.

Still in overall I am quite satisfied with the overall build with that price point.

@Hummie The inner and outer side of the bearing seems to be aluminum while the rim that holds it in place is definitely steel.

@laurnts thanks for the review! How about a link so we can see the the online description?

Yes here it is
http://loftyambition.en.alibaba.com/product/60378436802-801618327/Electric_longboard_hub_motor_wheel_seal_design_prevent_water_and_sand.html

I’ve also just noticed they are 110kv, which means larger torque.
But yea I don’t know how how they wound the motor with what diagram.
So performance wise with other hub motor with similar specifications in real life condition are questionable.

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110kv for a hub motor, especially with a wheel so big…I ride 100kv with 80mm diameter wheel and on 12s easily hits 35mph

I’m still confused by your answer. Please bear with me. The bearing itself is surely all steel. The two parts the bearing sits against , the shaft and housing, are they both steel?

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@hummie Hmm okay if you say so, I am not a metal expert but it make sense that the bearings are steel. The shaft and the housing is definitely steel both back and front cover. They are really heavy, I mean seriously heavy.

I am not sure why you asked this, but I believe they should be made out of very strong material. The cover of the hub motor act as a rim. They are the one responsible to hold the load of the board. They have to be very round in order to keep the small gap between the stator axle and the permanent magnet around the motor to avoid friction. If the cover by chance are slightly bend, the rotation of the hub motor could not be perfect. It could cause friction, wobble and heat. This also applies if the small bolts are not being properly mounted and tightened.

Well done mate. But I still prefer gear system. Maybe someday you should consider going back to drive belt world. Same as bikes and cars with trams can change gear ratio! Bravo!