My attempt at a lightweight EMTB with torque based PAS

[HrKlev]

I've had a few hard workouts on single trails on this bike now, and must say that Im really happy I tested out this motor. The axle exit does not seem to be a problem at all. I let it peak at 750w now, with phase amps at 32A, which translates to about 85NM at the crank, so it should be pretty close to the "250w" commercial ebikes that is populating the trails around here. Weird thing is it feels way more powerful than both the 75sx and the g370 and it does not heat up like they did. No need for oil cooling at the levels I am running. So I guess I ran those smaller motors way out of their efficiency sweet spot.





I did mess up slightly when I installed the temo sensor, and killed one if the halls, so I am running it sensorless. Only notice it during startup from standstill thanks to the electric freewheel feature. And a new hall sensor biard was $6, so I ordered a couple of them and another motor for the fatbike.

Oh, and drew up some adapters and custom bolt on sprockets. The fatbike have a 30 tooth chainri g, so I had to make the adapters without the corners to keep it from making contact with the chain.



Had my first chain drop in a while when I was riding down a rock garden at top gear (slackest chain). So need to fab up a chain guide...

 

[HrKlev]

Got the motor for the fatbike, and soldered in a new hall sensor board in the other motor that I had damaged. I am impressed in these motors. They seem to conduct heat a lot better than the other motors I have tested. The outer shell heats up and helos the motor temp to stay below 70 degrees, even when I am using way more assistance than I normally use. In fact the baserunner hit thermal rollback before motor got hot when I stress tested it. So no need for ATF on these. And spare gears and halls are cheap and available, unlike the bafang g370.





Also found out that my derailer clutch was sticking, so thats probably why the chain popped.... Fixed now, so I think I will get away without a chain guide.

Apart from replacing stuff that breaks and normal maintenance I think I am calling these bikes finished now. They have about the same power as the commercial ebikes, but is lighter than most if them. Probably a lot less sophisticated in power delivery than the factory ebikes, but I havent tried one yet, so I live happily not knowing. Not tempted by that propriarity stuff right now.

End result on my scale:
Liteville 20.8kg/45.8lb
Fat Tony: 21.5kg/47.4lb

 

[Grantmac]

Are you using the fast or slow winding on the Q100H? What sprocket? Does it match your cadence or can it outspin your legs?

 

[HrKlev]

I am using the 201rpm version. It spun like 250rpm out of the box without field weakening. Idk why, maybe something with the baserunner?
17-32 gearing.
With 5A of field weakening it gives full support up to 130-140 cadence, which is great when building momentum to get up small obstacles. It spins faster if I throttle it, but its not full power anymore.

 

[Vbruun]

Where did you get it from? Topbikekit?

 

[Grantmac]

That sounds just about perfect. So many DIY mids want to run far too high cadence.

Given the low cost of entry I'm very tempted to give this a try.

 

[HrKlev]

Where did you get it from? Topbikekit?

Yes, Q100H is from topbikekit. In fact all my motors are from topbikekit.

That sounds just about perfect. So many DIY mids want to run far too high cadence.

Given the low cost of entry I'm very tempted to give this a try.

That is my experience as well. Except the tsdz2, which is too slow :lol:

As long as you can fab up the motor mount and are used to a little DIY projects, it is not a big deal to put it together. Took some time to get the controller and CA tuned in, but not that bad. LMK if you need files for the controller/CA or drawings for chainring adapter or sprockets, and I can upload mine. Not saying they are perfect, but they are doing a decent job for me

 

[Grantmac]

Well it's this or the Lightest drive, which wouldn't be that much more costly if shipping prices come back down to earth.

The things I like about your setup is that it uses a big enough drive pulley to not be hard on chains and replacement parts are cheap and available. The idea of having a hub motor whirling around isn't super appealing, but it's so small you also can't see it in your builds.

 

[HrKlev]

Freewheel made a whoopsie today :?



Partly my fault for not catching the whole freewheel somehow had come loose and started to disassemble itself. So it was all wobbly. By the time I saw it the pawls had been chewed to death (6 is missing, the 2 in picture is stuck). So I had to feather it home with throttle. I ordered a couple spares, as I was partly expecting the freewheel to be the first bit to go... So bike is in business again already.

 

[HrKlev]

Well it's this or the Lightest drive, which wouldn't be that much more costly if shipping prices come back down to earth.

The things I like about your setup is that it uses a big enough drive pulley to not be hard on chains and replacement parts are cheap and available. The idea of having a hub motor whirling around isn't super appealing, but it's so small you also can't see it in your builds.

Yeah, if the lightest was shipping tiday, and I knew it would be as great as it seems, I would probably not built this. But Im not very patient.... And not being able to tune the software myself is not appealing to me either. If its perfect, its not a problem, but what is perfect for one person is usually not for another. So until I see some really awesome reviews, Im sticking to this

 

[Grantmac]

I have concerns about the tiny drive cog on the Lightest eating chains and being noisy. If there are good reviews this fall I'll probably jump on one.

Repurposing hubs is still very much on my mind though. Either like this or as a left hand drive geared solely to assist on steep hills.

 

[andrea_104kg]

Congratulations on your construction, I only see this beautiful tread gold!
I did a similar thing with a yalu motor kit, modifying the transmission with a mini bke chain and 12-80 ratio. Anyone who wants can see the photos here
http://www.jobike.it/forum/topic.asp?TOPIC_ID=79757&whichpage=1
I have an idea to use aikema motors so that only the axis turns but it's hard to explain :-( and obviously I don't know the resistance ..

 

[HrKlev]

Actually I found that thread this winter and have read it with google translate. Very, very nice build! I was considering the yalu motor myself, and using a baserunner with the cyc bb and freewheel, to get the e-freewheel function and torque sensor. I like the DD motors because of their simplicity, silence and heat shedding capabilities, but they are a bit heavy. If this q100h motor is about as reliable as the q75sx, it should be OK anyway. It is not quite as silent as the q75sx or a DD, but still much more quiet than the tsdz2.

Because of the dual reduction in these motors I dont think it is possible to make the shell stationary and the axle spin, unfortunately.

 

[andrea_104kg]

no, it's possible, an italian make it in 2014
http://www.jobike.it/forum/topic.asp?TOPIC_ID=34026
this it's your q75.
I don't know how he did it but I have an idea, even a very simple one. I will try to explain but it is difficult ... remove the three screws that hold the plate in the first photo. Under it you need to thin it so that it no longer enters the pin of the gears and is free to turn. Obviously the pins get weaker but I don't think much ...
Do you know the 3 screws where you fix the pinion? You have to remove them, inside the motor the 3 holes where they screw into the free wheel, you have to put some screws that are fixed to the plate underneath. In this way the whole plate turns and you can always use the free wheel anyway. on the outside you have to put a second bearing where the axle comes out (so you have to use a rear motor) to prevent the pin from being pushed back.
I don't know if I was able to explain myself, it's difficult ... :-(



Unfortunately I don't have a mechanical workshop and to do a good job it would take a lathe ..

 

[andrea_104kg]

where do you buy the torque sensor and freewheel?

 

[HrKlev]

Very interesting thread. I think I understand what he did, but I need to go and take a look at the motor to get my head around it.

But even though it is interesting, I dont really see why you would do all that custom work to avoid the shell from spinning? Please enlighten me Welding up a couple dropouts and getting a custom sprocket watercut is dead easy, and you just need to bolt the sprocket to the motor and go. Not saying I will not try it after a while, though. I can never stop modifying things, its like an obsession

The torque sensor and freewheel is bought as a spare part from cycmotor, https://www.cycmotor.com/cranks?page=3 . Freewheel Im using is gen 2.

 

[andrea_104kg]

There are 2 problems with the rotating motor ...
1- mud could stick to the engine
2- how do you prevent the motor from spinning backwards? the motor cannot be touched in the frame
where do you find the pinions for the engine?
I have no experience in the use of the CA, is it used with a normal control unit for hub motors?

 

[HrKlev]

Mud has not been a problem (at least so far), and there are loads of it here Do you have thisnproblem with the yalu motor? I had a huge stick jam the drivechain, but thats would have happened anyway.

Not sure if Inunderstand correct, but do you mean the motor mount? It is just a rod going between the two outer mounts, keeping the mount from rotating backwards. Two huge wrap ties keeps it from spinning forward (could use a big hose clamp or something more fancy if you dont like wrap ties) same principle as cuclone or cyc. The mount for the liteville bike got a little overkill, I just used whatever I found atm in the garage. The mount for the fatbike needed to be a little more delicate where it rest against tve frame because of carbon.



The CA unit is a kind of a controller for the controller. It takes signals from throttle, torque sensor, cadence sensor, speed sensor, temp sensor and shunt, dles whatever you tells it to, and just sends a throttle signal to the controller. So you can make every controller work with it.

I have mentioned a few times now, but the base- and phaserunner controllers from grin ha a geature called electric freewheel. It sends a programmable amount of motor amps while you are coasting. It is meant as a way to overcome the cogging from a non-clutced hub motor while you are pedaling, but it is an AWESOME feature for everyone using a mid motor. What it does is keeps the motor engaged with the drivetrain, so the response time when you have stopped pedaling for a little while (like avoiding pedal strikes) are really short, better than anything I have tested so far. And there are no more clunking whenever the motor catches up with the drivetrain. Also, you can shift gears without pedaling while going downhill. Its such a great feature.

 

[ford]

Such a great bike- with really interesting ideas and it sounds like it rides wonderfully. Inspiring.
Thank you !

 

[HrKlev]

Such a great bike- with really interesting ideas and it sounds like it rides wonderfully. Inspiring.
Thank you !

Thanks! Glad you enjoyed it

 

[andrea_104kg]

thank you very much for the replies. Now I understand how you prevent rotation. I had in mind the yalu motor where it is not possible because there is no thru axle in the motor.
In fact I don't have big problems with mud, but I have always avoided going there for fear ... I have the controller under the frame and I am always afraid that the motor will fill it with mud.
Unfortunately the phaserunner controller costs too much!
I think it's better to buy the complete x1 stealth kit!
The cost of the motor, CA, torque sensor, phaserunner is higher than the complete kit.

 

[HrKlev]

thank you very much for the replies. Now I understand how you prevent rotation. I had in mind the yalu motor where it is not possible because there is no thru axle in the motor.
In fact I don't have big problems with mud, but I have always avoided going there for fear ... I have the controller under the frame and I am always afraid that the motor will fill it with mud.
Unfortunately the phaserunner controller costs too much!
I think it's better to buy the complete x1 stealth kit!
The cost of the motor, CA, torque sensor, phaserunner is higher than the complete kit.

Im using the baserunner standalone, its a little cheaper and lighter than the phaserunner, and enough for this duty. But I agree that maybe it is better to buy a x1 stealth for most. The lack of tunability, response and noise are a couple cons to that I would not enjoy, though. But it seems a lot better than many other options out there!

 

[Grantmac]

Spinning the axle would allow quite a bit more weight reduction and mounting options.

 

[andrea_104kg]

I came up with an idea to sell everything much cheaper. It should be known if the torque sensor sold by cyc is compatible with this control unit
https://www.aliexpress.com/item/4000038619326.html?spm=a2g0o.detail.0.0.1f908f3dt6wCTK&gps-id=pcDetailBottomMoreThisSeller&scm=1007.13339.169870.0&scm_id=1007.13339.169870.0&scm-url=1007.13339.169870.0&pvid=690fbbf9-a148-4ed4-9a4d-c5512815ffa7&_t=gps-idcDetailBottomMoreThisSeller,scm-url:1007.13339.169870.0,pvid:690fbbf9-a148-4ed4-9a4d-c5512815ffa7,tpp_buckets:668%230%23131923%2380_668%230%23131923%2380_668%23888%233325%233_668%23888%233325%233_668%232846%238112%231997_668%235811%2327177%2327_668%236421%2330827%23686_668%232717%237558%23176_668%231000022185%231000066058%230_668%233468%2315615%23662_668%232846%238112%231997_668%235811%2327177%2327_668%236421%2330827%23686_668%232717%237558%23176_668%233164%239976%23550_668%233468%2315615%23662&&pdp_ext_f=%7B%22scene%22:%223339%22%7D

The control unit works with this torque sensor erider
https://www.aliexpress.com/item/33030138390.html?spm=a2g0o.store_pc_allProduct.8148356.69.479253ebiINp99

The page shows the operating data, but the cyc page does not contain the sensor data. So I can't know if they are the same. do you know the data of the cyc sensor?
Thank you!

 

[HrKlev]

I have attached the pdf I got from CYC when I asked for a datasheet. It does not show a sensor with the correct flange, but the other things seemed to be correct (I was mainly looking for wiring colors). I had to adjust the NM/V scale slightly after testing with weights. This was for the 68-83mm version I bought for my FS bike.

But, when I some months later ordered a 100mm version for the fatbike, the torque sensor had 36 poles. And the torque scale was quite a bit different. Colors for wiring was the same, and operating voltage seems to be the same (the CA outputs 10v for torque sensor). I asked them for a datasheet, but they said it was the same.... So idk. Not sure if you will receive a 18 or 36 pole unit if you order a 36 or 18 pole unit if you order a 68-84 today...