10kg+ hub motors, too much unsprung weight?

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BDamari   10 mW

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10kg+ hub motors, too much unsprung weight?

Post by BDamari » Jun 04 2020 5:22am

I want to build a 100kmh/60mph machine. I have seen the MXUS 3k/QS205 motors, even lifted one just to see how heavy they are.
Thing is, at speeds above 60kmh/40mph, I'm not sure that a mtb suspension can handle road imperfections and the occasional manhole cover, with the insane momentum from the motor on the rear end.

Even Tony (Vortecks on Youtube) has top-notch mtb suspension on his most recent build, and he said it himself: no matter how soft he tunes the suspension to be, he just finds the ride uncomfortable at high speed.

Say you have a good ebike enduro frame with the same top-notch suspension. Can you achieve a ride almost as comfortable as a motorcycle with mtb suspension?

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DogDipstick   10 kW

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Re: 10kg+ hub motors, too much unsprung weight?

Post by DogDipstick » Jun 04 2020 7:26am

BDamari wrote:
Jun 04 2020 5:22am
I want to build a 100kmh/60mph machine.

Even Tony (Vortecks on Youtube) has top-notch mtb suspension on his most recent build, and he said it himself: no

Can you achieve a ride almost as comfortable as a motorcycle with mtb suspension?
I got the little 205V1, right under 10Kg. I just bought a V3 to play with also, cause my V1 overheats to much.

It is installed in an excellent MTB suspension system, aluminum bike for a total of 85lbs on a 40lb bike. Handles the road great upwards of 47mph. No weaves, wobbles, bottoming, or topping out. No slams, no weird things. When it comes to handling. Hey even jumps like a horse.

Tony is wrong, or a bicycle rider, but not a motorcycle racer. Why in the world would you tune your suspension "Soft" for speed?

Speed means hard. When I first got my ZX10r I was surprised by how hard it was sprung... and the same with my ZX9r. Kinda silly making them compress on a flick in after a braking.... they dont move to far.. from up high there... You have to be going into the turn at like 130mph or else you wont compress.. lol.. I had a CBR that was so soft it was comical. Bottom on a hard wheelie.. but it was a comfy commuter.

Racing motorcycles use hard springs, soft is a NO GO for speed. Race cars also use HARD springs. Like 2" travel. Not the 4"-6" of MTB.

The race track better be flat. Lol. For the speed. Travel is not needed for a true speed machine.

Travel is for soaking up bumps and not bouncing your girlfriend off the back. Dont go fast with your girlfriend on the back on a racetrack, pls.

My ebike is soft, very soft with lots of travel with a freeride triple tree 110mmx20mm fork with replaceable spring. I may go harder in the front. The fancy 4-point suspension is amazingly good in the rear.. the front fork could be better, but I never had a problem with the progression of load on the DW Link 4-point. I am sure there are junk suspension systems out there that are.. junk. Single pivot, or pivots on the rear triangle, I try to stay away from these designs for ebikes, they are weak and do not articulate well. Triangle must be strong. My bike is great on road, I am sure it could do 60-70mph easily with good stability.

I have a 600 lb spring on the rear and it feels fine. I do not notice the weight of the medium heavy hub much at all... No slams or jars... unless you hit the bank wrong on an angle , the mass of the motor will "jar" the bike a little. Not much, but you know it is not good for the bearings on the bike frame ( and probably not the best for the frame in general.)

Suspension tuning for the square bumps round bumps, hills, fast vs slow, ect.... and the use case ....is tuned for the ride, and rider. Cant have both. On potholes and manhole covers in suburbs my bike is fine at its 40mph. Even though it is a 5" MTB "Free Ride " bike... with lots of soft travel.

I'll let you know how the bigger motor feels, but I do not think it will be to much trouble, on an on road bike. It is only about 10lbs more than my V1.

If you have a very hard suspension on a normal road, ( car or bike) ( not a race track velvet smooth, or a dirt trail jump-off-the-bump)... the hard spring just makes you bounce a little . Bounce bounce. At low speed. Over potholes and expansion joints.. manhole covers.. ect.
83.1v of Ironhorse XC.. :) :bolt: by Chevy :bolt: :D Broke 10 horsies :twisted: (..about 80% healed..).. :? Anybody.. what equals √3 times the line to neutral voltage? Asking for a friend.. :| (gottenymoem4115thangs?Yall?) :confused: Fabricator @ BSECo. Inc.

BDamari   10 mW

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Re: 10kg+ hub motors, too much unsprung weight?

Post by BDamari » Jun 04 2020 8:37am

DogDipstick wrote:
Jun 04 2020 7:26am
BDamari wrote:
Jun 04 2020 5:22am
I want to build a 100kmh/60mph machine.

Even Tony (Vortecks on Youtube) has top-notch mtb suspension on his most recent build, and he said it himself: no

Can you achieve a ride almost as comfortable as a motorcycle with mtb suspension?
I got the little 205V1, right under 10Kg. I just bought a V3 to play with also, cause my V1 overheats to much.

It is installed in an excellent MTB suspension system, aluminum bike for a total of 85lbs on a 40lb bike. Handles the road great upwards of 47mph. No weaves, wobbles, bottoming, or topping out. No slams, no weird things. When it comes to handling. Hey even jumps like a horse.

Tony is wrong, or a bicycle rider, but not a motorcycle racer. Why in the world would you tune your suspension "Soft" for speed?

Speed means hard. When I first got my ZX10r I was surprised by how hard it was sprung... and the same with my ZX9r. Kinda silly making them compress on a flick in after a braking.... they dont move to far.. from up high there... You have to be going into the turn at like 130mph or else you wont compress.. lol.. I had a CBR that was so soft it was comical. Bottom on a hard wheelie.. but it was a comfy commuter.

Racing motorcycles use hard springs, soft is a NO GO for speed. Race cars also use HARD springs. Like 2" travel. Not the 4"-6" of MTB.

The race track better be flat. Lol. For the speed. Travel is not needed for a true speed machine.

Travel is for soaking up bumps and not bouncing your girlfriend off the back. Dont go fast with your girlfriend on the back on a racetrack, pls.

My ebike is soft, very soft with lots of travel with a freeride triple tree 110mmx20mm fork with replaceable spring. I may go harder in the front. The fancy 4-point suspension is amazingly good in the rear.. the front fork could be better, but I never had a problem with the progression of load on the DW Link 4-point. I am sure there are junk suspension systems out there that are.. junk. Single pivot, or pivots on the rear triangle, I try to stay away from these designs for ebikes, they are weak and do not articulate well. Triangle must be strong. My bike is great on road, I am sure it could do 60-70mph easily with good stability.

I have a 600 lb spring on the rear and it feels fine. I do not notice the weight of the medium heavy hub much at all... No slams or jars... unless you hit the bank wrong on an angle , the mass of the motor will "jar" the bike a little. Not much, but you know it is not good for the bearings on the bike frame ( and probably not the best for the frame in general.)

Suspension tuning for the square bumps round bumps, hills, fast vs slow, ect.... and the use case ....is tuned for the ride, and rider. Cant have both. On potholes and manhole covers in suburbs my bike is fine at its 40mph. Even though it is a 5" MTB "Free Ride " bike... with lots of soft travel.

I'll let you know how the bigger motor feels, but I do not think it will be to much trouble, on an on road bike. It is only about 10lbs more than my V1.

If you have a very hard suspension on a normal road, ( car or bike) ( not a race track velvet smooth, or a dirt trail jump-off-the-bump)... the hard spring just makes you bounce a little . Bounce bounce. At low speed. Over potholes and expansion joints.. manhole covers.. ect.
Thanks for the detailed reply :)

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Re: 10kg+ hub motors, too much unsprung weight?

Post by momus3 » Jun 12 2020 9:59pm

You're never going to get a bike to be as stable or ride as well as a motorcycle. The motorcycle is purpose built for the speeds it's used at, and the weight (considerably more than an eBike), rider position, stiffer frame and low center of gravity all make it much better handling at speeds. This might be a case of horses for courses.

markz   100 GW

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Re: 10kg+ hub motors, too much unsprung weight?

Post by markz » Jun 12 2020 10:19pm

Bicycles were engineered for human pedal power and to go 20-25mph. Some people on Endless Sphere are riding big motors at fast speeds on bicycle frames, but 60mph on a bicycle just seems like its too much. You might as well just buy a motorcycle, plate it, insure it, register it and ride it. If you dont want that, then you have to take 60mph off the table or be willing to custom fabricate your bicycle frame, or buy a frame capable of that kind of speed and power. Millions of dollars are spent on engineering frame geometries for bicycle brands with human power and human speeds. Motorcycle brands spend millions too. One or the other for 60mph, or gamble. Just hope you have a good health coverage plan for 60mph bicycle idea.

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Re: 10kg+ hub motors, too much unsprung weight?

Post by DogDipstick » Jun 13 2020 7:20am

markz wrote:
Jun 12 2020 10:19pm
....or be willing to ....
Yeah then the whole thing about how much do you really trust your one off design? Donor frame or none... why even trust 60mph to a overloaded bicycle frame? Choose one, either on or off road.. and build for that. I say.

Real motorcycles are tested preeety well pre-production, for safety.

Impacts break stuff... hard landings, jolts.. curbs, bangs and thunks.. ( technical terms.. ) .. hitting stuff... Speed inherently ( IF it is "smooth speed") itself does not put extreme structural loads on a vehicle.. its the road surface below that does Z( whether flat racetrack, city road, dirt trail.. ) .. so design the bike for a single purpose. On, Off, or Dual Sport... gonna compromise either way.

I got my qs V3 in hand. Damn this thing is friggin heavy.
83.1v of Ironhorse XC.. :) :bolt: by Chevy :bolt: :D Broke 10 horsies :twisted: (..about 80% healed..).. :? Anybody.. what equals √3 times the line to neutral voltage? Asking for a friend.. :| (gottenymoem4115thangs?Yall?) :confused: Fabricator @ BSECo. Inc.

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Re: 10kg+ hub motors, too much unsprung weight?

Post by markz » Jun 13 2020 1:15pm

DogDipstick wrote:
Jun 13 2020 7:20am
I got my qs V3 in hand. Damn this thing is friggin heavy.
Yup, means more power :thumb:

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Re: 10kg+ hub motors, too much unsprung weight?

Post by flat tire » Jun 13 2020 3:21pm

Here's a good answer to your question OP

Whether hubs are too much depends on what you want to do. If you want to ride on the street with full suspension they are fine unless you want to take big jarring sheer transitions, potholes or curbs at speed. Actually, if you want to do that at 60 mph on a bicycle you will have other issues even with a mid drive.

Anyway, if you want to go fast offroad on anything other than smooth surfaces you don't want any kind of hub motor at all. Mid drive king on very rough surfaces.

For just street riding, even bursts to 60+ mph, a 30+lb hub motor is fine if the rest of your system is up to it. The biggest problem will be your brakes. You need a motorcycle brake in front if you want to panic stop a bicycle kitted out with you, a heavy hub and all accoutrements from 60 mph. Many people get away without doing this, but you need to be mindful that the consequence is you will not be able to stop hard in an emergency at high speed.

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Re: 10kg+ hub motors, too much unsprung weight?

Post by john61ct » Jun 13 2020 5:47pm


DogDipstick wrote:I got my qs V3 in hand
Does that mean 273?

Link?


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Re: 10kg+ hub motors, too much unsprung weight?

Post by john61ct » Jun 13 2020 5:50pm


flat tire wrote:Anyway, if you want to go fast offroad on anything other than smooth surfaces you don't want any kind of hub motor at all. Mid drive king on very rough surfaces.
But at slow speeds, hubs can handle them? Need lots of power for heavy cargo / tandem, cheap.


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DogDipstick   10 kW

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Re: 10kg+ hub motors, too much unsprung weight?

Post by DogDipstick » Jun 13 2020 6:37pm

john61ct wrote:
Jun 13 2020 5:47pm
DogDipstick wrote:I got my qs V3 in hand
Does that mean 273?

Link?
Nah just a 205. Definitely a "Two hand " motor. Got it on Amazon lol.
83.1v of Ironhorse XC.. :) :bolt: by Chevy :bolt: :D Broke 10 horsies :twisted: (..about 80% healed..).. :? Anybody.. what equals √3 times the line to neutral voltage? Asking for a friend.. :| (gottenymoem4115thangs?Yall?) :confused: Fabricator @ BSECo. Inc.

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Re: 10kg+ hub motors, too much unsprung weight?

Post by flat tire » Jun 13 2020 8:01pm

john61ct wrote:
Jun 13 2020 5:50pm
But at slow speeds, hubs can handle them?
At VERY slow speeds. If you only need to cross a small amount of rough terrain, and don't mind going very slowly so as not to damage things, hubs are OK. What ends up happening if you try to go fast on a hub over rough terrain like roots is you will run into issues like flatting the tire even with higher pressure and mechanically damaging the phase windings inside the motor so that they short against the stator.

This is especially possibly if the motor is hot and the insulation on the magnet wire is weakened. Keep in mind these hub motors are almost never potted, and the windings are mostly free to move around if sufficiently stressed.

Hub motors keep the motor insulated and suspended so you avoid pretty much all these issues, at the expense of other bs.

Whether a hub or mid drive is ideal depends on how, where, and for how long you need to ride.

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Re: 10kg+ hub motors, too much unsprung weight?

Post by markz » Jun 13 2020 9:13pm

If you will be bouncing off roots and rocks at speed, and jumping around on the bicycle, a full suspension bicycle with a mid drive is the way to go for trail riding, but placing the motor below the tube wont be good for clearance, but you can place it above if there is room and its not blocked by suspension mounts. If its blocked, placing the motor below the tube and bolting on a guard would suffice as well. I would look at the Lightning Rods mid drive kit, if he is still selling them a simple search will find out, I just dont feel like taking my hands off the keyboard atm, until Im done this post.

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Re: 10kg+ hub motors, too much unsprung weight?

Post by Tony01 » Jun 30 2020 2:42am

Yeah it’s tough to find the traction with the qs205 sometimes, find it skipping forward on acceleration clear on up to 80mph. It warns you in a hard lean with the stutter as well. But I like it. It’s kind of between a hardtail and a full suspension sometimes, though maybe I just need a more expensive shock...
I don't always listen to Pantera.... but when I do, SO DO THE NEIGHBORS :D

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Re: 10kg+ hub motors, too much unsprung weight?

Post by markz » Jul 01 2020 11:08am

Tony01 wrote:
Jun 30 2020 2:42am
Yeah it’s tough to find the traction with the qs205 sometimes, find it skipping forward on acceleration clear on up to 80mph. It warns you in a hard lean with the stutter as well. But I like it. It’s kind of between a hardtail and a full suspension sometimes, though maybe I just need a more expensive shock...
Maybe a motorcycle shock

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Re: 10kg+ hub motors, too much unsprung weight?

Post by Compoundbike » Jul 01 2020 2:01pm

Those things are eating so much Battery, it's not fun.
My 160 cells brought me only 15 miles of riding. :confused:

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Re: 10kg+ hub motors, too much unsprung weight?

Post by Battosaii » Jul 01 2020 6:32pm

Compoundbike wrote:
Jul 01 2020 2:01pm
Those things are eating so much Battery, it's not fun.
My 160 cells brought me only 15 miles of riding. :confused:
That's why I'm going to more cells. The 24s15p pack I'm building uses 360 cells. I was even thinking of adding an extra P group or two if it will fit in the battery box.

May be getting a qs205 v3 cause from what I've seen the extra weight of the 273 isn't worth the trouble.

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