current selection of rear geared cassette hubs

Comrade

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I'd like to electrify a recumbent trike, and I think I narrowed it down to what I need/want.


  • Reason for electrification: go further without over exhaustion. Don't need help climbing hills. I have gears on the front and a 9SP mega-range in the back. I need the exercise. Electric to basically coast at maybe 15-16mph on flat stretches to relax legs here and there.
  • Max speed I'd ever want to go: about 20mph
  • Total weight: approx. 250lb without electric gear
  • Drive wheel size: 24"

So based on that, I think I just need a small-medium rear hub. Being quiet would be a nice to have. I know SX2 and MG310 have helical gears. Anyone else? There's the Q128C and XF08C, which I think are straight gears.

What are the recommendation in late 2021 and early 2022 for a hub that might fit the bill?
 
The Q128C comes in 201rpm. Is that absolute maximum unloaded? If so, what would be the RPMs at max efficiency?
 
Comrade said:
I'd like to electrify a recumbent trike, and I think I narrowed it down to what I need/want.


  • Reason for electrification: go further without over exhaustion. Don't need help climbing hills. I have gears on the front and a 9SP mega-range in the back. I need the exercise. Electric to basically coast at maybe 15-16mph on flat stretches to relax legs here and there.
  • Max speed I'd ever want to go: about 20mph
  • Total weight: approx. 250lb without electric gear
  • Drive wheel size: 24"

So based on that, I think I just need a small-medium rear hub. Being quiet would be a nice to have. I know SX2 and MG310 have helical gears. Anyone else? There's the Q128C and XF08C, which I think are straight gears.

What are the recommendation in late 2021 and early 2022 for a hub that might fit the bill?
Only serious roadies w/ a minimalist install do much pedaling w/ the motor system off.
The way it works for Eriders who want to up the rider's input is to adjust the PAS power down and pedal "on top" of the motor. Even a light-weight system adds some weight and drag, maybe not much, but it's enough to take the fun out of riding an Ebike on pedal-power only and I would think that would apply even more with a trike.
At any rate, even with the lowest powered systems, 3 gears are the max most folks use and never the frt. chain ring. With a motor, spending the time shifting thru the gears actually slows one down.
Even if much shifting isn't needed, the cassette's light weight is nice compared to the clunky ENP free-wheel that's required for most hub motors.
I've built 4 bikes w/ mini-motor/cassette combos, 3 w/ the Q100C and one w/ the Bafang SWX02 and the extra width of the Q100C was a problem on 2 out of 3 of the builds. It's form factor is such that it trades outside diameter for width to get a reasonable amount of stator area. Then, swapping in the longer cassette spline off-sets the center of the rotating ASM even more and requires "dishing" to get the rim centered. Of the 3 Q100C's, one fell in w/ little off-set, one required an extreme amount of off-set and the last I just gave-up on and went w/ the Enoch DNP. It all depends on how the chain-stays are built. The Bafang is larger and taller and slightly less wide and it's install was straight-forward. I would suggest staying away from the short and squat mini's like the Q series and the MXUS if you want to use a Cassette.
Today most new hub motors are quiet (irregardless of the type of gears) on low-powered systems. And even then, the controller has a lot to do with emitted sound. Sine waves are quieter than square-waves.
 
Can we see a pic or a link for your trike. As it's good to figure out where all the pieces motor controller battery throttle will go before you purchase anything.
 
motomech said:
I would suggest staying away from the short and squat mini's like the Q series and the MXUS if you want to use a Cassette.

I think Q128 is a larger unit than Q100. So it might not be an issue. I'm still in early planning stages, and need to understand the basics like what speed motor I need. Say Q128C comes in 201rpm. Is that absolute maximum speed at rated voltage, or at peak efficiency?
 
I'm running a 135mm Q128C (36V, 328RPM) at 800 watts (overvolted to 44V) in my tadpole trike.
https://endless-sphere.com/forums/viewtopic.php?f=3&t=98760&p=1460895&hilit=terratrike+q128c#p1460895
Maximum speed at 36V pack is 23MPH.
Maximum speed at 44V pack is 28MPH.
Trike is setup with 20" wheels.
Typically I use it as transportation around golfing community (lots of golf cart lanes and bike trails) and town....rarely ever peddle.
I get my workouts on a roadbike 100 miles/week. I also can swap out the rear motor-wheel for stock wheel in two minutes if I want a good trike-workout.
I dumped my front 3X crankset for a 1X setup with 8SP mega-range in back.
Total weight of trike is 49lbs. I'm 175 lbs.
IMG_0335.JPG
 
pullin-gs said:
I dumped my front 3X crankset for a 1X setup with 8SP mega-range in back.

There are some hills on my trails that are probably around 40% at times. Guys in lycra take them slow in granny gear while huffing and puffing. Everyone else pushes their bike up the hill. And pedestrians of AARP age take breaks. No way would I be able to go up without a 22T on the front.

I was intrigued by mid-drives, but the idea of a single (largish) chainring on the front killed that idea. Besides, I enjoy too much crawling up these hills without falling over like all the inferior 2 wheelers would. :mrgreen:
 
Loaded is around +/- 80% of unloaded rpm. Max efficiency would be the highest rpms. If your really talking about using the least amount of watts then use the pedals more.

Can not pedal hard anymore. Still ride for exercise and like todo long rides but limited to about 4hrs so farther must be faster but not to fast. Not going to get into motor selection. Would suggest not to low of power and target motors top speed 3-5mph more than you plan to ride at. Unless you don't mind lag and want max efficiency. Use PAS/torque with a throttle and a CA to fine tune power and assist. At times I ride with groups the slow groups don't need assist, the speeders it varies with how fast they try to go. Have 7 PAS levels and have 3 power levels for throttle. Have my PAS setup to subtract watts as cadence increases. All of this allows me get to get a steady work out no mater how far or fast (within reason) my ride is or who I ride with.

May find out that 75w - 150w will allow you to ride further than you thought.

by Comrade » Oct 23 2021 10:45pm

The Q128C comes in 201rpm. Is that absolute maximum unloaded? If so, what would be the RPMs at max efficiency?
 
Comrade said:
pullin-gs said:
I dumped my front 3X crankset for a 1X setup with 8SP mega-range in back.

There are some hills on my trails that are probably around 40% at times. Guys in lycra take them slow in granny gear while huffing and puffing. Everyone else pushes their bike up the hill. And pedestrians of AARP age take breaks. No way would I be able to go up without a 22T on the front.

I was intrigued by mid-drives, but the idea of a single (largish) chainring on the front killed that idea. Besides, I enjoy too much crawling up these hills without falling over like all the inferior 2 wheelers would. :mrgreen:
Living/riding in Florida has its perks. :)
Unless you are superman no way my setup will work.
Motor will sustain 18 MPH at 10% grade for about .25 mile. Anything steeper for sustained periods would require a small ring and rider power. Motor could help with climb, but would need to drop watts down to below 500 (800 sustained for more than a minute or two with slow airflow would smoke my motor).
Now if you went to a 20" rear wheel with 201RPM motor could give you a climbing beast! But top-speed would drop below 16 MPH even if you overvolt it to 44V! Anything higher (overvolt to 48V for example) with Q128C and you will over-RPM motor (ask me how I know!) and throw magnets.
 
ZeroEm said:
Loaded is around +/- 80% of unloaded rpm. Max efficiency would be the highest rpms. If your really talking about using the least amount of watts then use the pedals more.

I'm still not clear, so when it says "201 RPM" motor, is that when the motor will be at its highest efficiency but can still spin slightly faster?
 
pullin-gs said:
Now if you went to a 20" rear wheel with 201RPM motor could give you a climbing beast! But top-speed would drop below 16 MPH even if you overvolt it to 44V! Anything higher (overvolt to 48V for example) with Q128C and you will over-RPM motor (ask me how I know!) and throw magnets.

This is a newb question. So if we stick to Q128, it seems to be sold in 201 rpm and 328 rpm version. And in 36v and 48 versions.

  • 36v 201
  • 36v 328
  • 48v 201
  • 48v 328

Do you think they are all identical physically except for the motor windings? I would have guessed yes. But the over-RPM issue that you bring up suggests otherwise.
 
Comrade said:
ZeroEm said:
Loaded is around +/- 80% of unloaded rpm. Max efficiency would be the highest rpms. If your really talking about using the least amount of watts then use the pedals more.

I'm still not clear, so when it says "201 RPM" motor, is that when the motor will be at its highest efficiency but can still spin slightly faster?
It can indeed spin faster.
For my 36V 328 RPM motor, 328 is the RPM of the motor when loaded at rated watts (500) using rated voltage (36V pack).
For my application I am indeed seeing close to rated RPM (328 RPM motor) when running loaded at 500W with 36V LIPO (42V fully charged) pack.
Unloaded full throttle motor spins at around 425RPM.
.....and for my configuration speed & RPM go way above this because I overvolt using 44V pack....I dont recommend overvolting though if you have steep/long hills.

201 and 328 use different gears.
 
Comrade said:
Do you think they are all identical physically except for the motor windings? I would have guessed yes. But the over-RPM issue that you bring up suggests otherwise.
They use different gearing.
Gears are not interchangeable because they are dependent on armature pinion teeth count (which is different for RPM version).
I believe the 201rpm uses 45/33 and the 328rpm 42/33....this seems like very little difference....however keep in mind that pinion teeth is lower for "45" version and higher for "42" version.
 
Once you pick a motor the best efficiency is at max rpm of that setup.
I'm still not clear, so when it says "201 RPM" motor, is that when the motor will be at its highest efficiency but can still spin slightly faster?

I do not know the Q128. All motors have a Kv (This is rpm's per Volt) this is set by the windings. For the chart below to be true then the Q128 would need to have 3-4 winding options
This is a guess, don't know if you are showing loaded or unloaded rpm.
36v 201 = 5.6 Kv
36v 328 = 9 Kv
48v 201 = 4 Kv
48v 328 = 7 Kv
The motors would be the same. Some people reglue the magnets so they don't come lose. I just would not run a small motor that hard for longevity. Best to get something more robust.
This is a newb question. So if we stick to Q128, it seems to be sold in 201 rpm and 328 rpm version. And in 36v and 48 versions.
36v 201
36v 328
48v 201
48v 328

They maybe changing the gearing in the motor. Just don't know.
Do you think they are all identical physically except for the motor windings? I would have guessed yes. But the over-RPM issue that you bring up suggests otherwise.
 
pullin-gs said:
Comrade said:
Do you think they are all identical physically except for the motor windings? I would have guessed yes. But the over-RPM issue that you bring up suggests otherwise.
They use different gearing.
Gears are not interchangeable because they are dependent on armature pinion teeth count (which is different for RPM version).
I believe the 201rpm uses 45/33 and the 328rpm 42/33....this seems like very little difference....however keep in mind that pinion teeth is lower for "45" version and higher for "42" version.

Interesting! And confirmed. I found an Ebay listing for replacement gears for the Q128 and they do sell different ones for the 2 speeds.

https://www.ebay.com/itm/264314269298

It looks like the gears are helical too, which should make them a little quieter.
 
I think I got the hang of motor speeds now and can narrow down the RPMs I should get. Thanks all! Now about temperature sensors. Strangely, I think none of the motors + controllers are aware of motor temperature? (except some Grin motors and cycle analyst?)
 
For the Q100 series, the "H" models offered "260" mid-speed range motors (yes, determined by the gear ratios, not windings), which for that micro-motor in 24" and 26" wheels, put the top speed in the "sweet spot" of low to mid 20's MPH.
The "201" was a little slow for my tastes @ 18 to 19 MPH and trying the 328" was an epic fail in a 26" whl. To use the"201" Q100C (no 260 avail.), I ran it it on 52 Volts, which brought it up over 20 MPH. Still a little slow, but it climbed well for a Q100.
 
pullin-gs said:
(ask me how I know!) and throw magnets.

What does this failure look/sound like? Just magnets rattling? Hub binding up?

I'm still afraid of front hubs. It just seems like any internal failure that would cause it to bind up carries a high probability of serious injury or death on an upright bicycle.
 
Comrade said:
pullin-gs said:
(ask me how I know!) and throw magnets.

What does this failure look/sound like? Just magnets rattling? Hub binding up?

I'm still afraid of front hubs. It just seems like any internal failure that would cause it to bind up carries a high probability of serious injury or death on an upright bicycle.

It sounds like a rattling/scraping noise for speeds above 10MPH (at point where RPM centripetal forces exceed magnet attraction to spinning stator. Motor could seize, however being that it is a geared motor with internal freewheel (so motor does not turn when coasting), wheel would never stop spinning due to motor seizing. However for direct drive motors it would be a different story.
FYI I'm still running my original Q128C motor that lost magnets. I tore down the motor and cleaned/glued magnets back on using JBweld. My other Q128C motor never had a problem....probably because I do not overvolt it.
 
motomech said:
For the Q100 series, the "H" models offered "260" mid-speed range motors (yes, determined by the gear ratios, not windings), which for that micro-motor in 24" and 26" wheels, put the top speed in the "sweet spot" of low to mid 20's MPH.
The "201" was a little slow for my tastes @ 18 to 19 MPH and trying the 328" was an epic fail in a 26" whl. To use the"201" Q100C (no 260 avail.), I ran it it on 52 Volts, which brought it up over 20 MPH. Still a little slow, but it climbed well for a Q100.

It looks like the Q128 in the cassette version has a 260rpm version available?

http://www.topbikekit.com/akm128cst-48v500w-rear-driving-hub-motor-cassette-motor-for-ebike-p-723.html

Unless I'm not reading something right.

Anybody know what does the ST in AKM128CST stands for?

AKM = company name
128 = series?
C = cassette
ST = ??
 
Comrade said:
It looks like the Q128 in the cassette version has a 260rpm version available?

Anybody know what does the ST in AKM128CST stands for?

AKM = company name
128 = series?
C = cassette
ST = ??
CST="Cassette"
Specifications for Q128C versions state 260.....but never have seen one actually sold anywhere.
 
pullin-gs said:
Specifications for Q128C versions state 260.....but never have seen one actually sold anywhere.

I asked topbikekit about the AKM-128 48V 260 RPM model and they said it uses the same gears as the 201 RPM model, so I suspect it's just a 36V 201 RPM being sold as 48V 260 RPM. But you threw magnets with that set up.

So I don't know what to think. Maybe spinning that motor that fast is generally ok, but with less safety margin than 201/328 models, and you were just a victim of chance.
 
You are worrying too much about hub motor durability. I did a search here punching in "Q128" and got 25 pages of threads. Then I narrowed it down using the search-word "magnets" and ended up with 2 pages. No mention of thrown magnets.
You are way more likely to have to replace the controller than the motor and some builders often have an extra controller thrown in the box when ordering the "kit". Heck, if you will sleep better at nite, order an extra motor. Since you already paying for freight, the extra weight gets pro-rated. It takes me about a half an hour to swap out a motor core.
And if all you want out of the top speed is 20 mph, get the "201" and run it on 52 Volts. 52 Volt packs cost little more the 48 V packs, especially if you factor in the increased capacity the extra Volts provide (V X A = W). The Q128 will handle 52 V easily. What kills hub motors are too high a speed range on steep hills where the climbing speed falls below 1/2 the top speed. The motor can't reach it's efficient rpm range, the controller tries to feed it max amps and the motor over-heats. This is why the "328" is not recommended in whl.s 24" and above.
If budget is not a concern, there are better mini's w/ a mid-speed range. Then you could run a 36V pack or whatever. But since you keep mentioning "efficiency" (an over-blown factor), be aware that for a given road speed, a motor run on higher Volts/ lower gearing will be more efficient than a motor running lower Volts/higher gears..
 
motomech said:
You are worrying too much about hub motor durability.

I'm not. I'm just too familiar with Chinese products, and how specs should always be taken with a grain of salt. All I'm doing is trying to figure out what I'm actually getting with a "48V 260 RPM" motor. :mrgreen:
 
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