Neatest Mid Mount?

motas

10 mW
Joined
Feb 1, 2019
Messages
20
Hey all,

Been trawling these forums for the last few days since I've suddenly decided I want an ebike, it's too hot for pedalling :flame: .

The bike I'd like to convert is a 2017 Ragley Blupig. I think it's a great candidate, and as a bonus I already own it. It's a chromoly enduro hardtail, very strong, very simple and a blast to ride. I want to keep the feel of the bike, and use it primarily on enduro tracks.

I'd like to keep the conversion as "factory" as I can get it, ideally with the motor/gearbox integrated into the frame. I have a welder, and I am not afraid to use it! I'm also a mechatronics engineer, so I have access to CAD, FEA and CNC, so custom parts are not beyond me.

So I am looking for some ideas and inspiration for very neat mid mount motors. I think my best bet is to make a cycloidal drive to gear a brushless outrunner down to around 100RPM pedalling speed, but my issue is how to get that power to the cranks without backfeeding the motor or my feet. The three options I am considering at the moment is:
  1. Spur or helical gears between the gear reduction output and the cranks, my issue here is width and how to fit a one way bearing to the pedals.
  2. A second cog on the chain, my issue here is that it is not as neat, and also whether I can get enough wrap on both cogs without additional rollers.
  3. Mount the cog to the gear reduction output and somehow feed my pedal power into that. My issue with this is it seems kind of complicated, big and heavy to achieve.

So does anyone have any great ideas or seen anything like this done before?

Thanks in advanced!
 
Bafang ultra mount, been done before:

https://electricbike-blog.com/2018/03/03/choppy-shloppy-build-your-own-ultra-max-specific-frame-and-get-riding-already/

If you want more power, same formula, but you make a 136mm cylinder with a cut somewhere, so you can put the cyclone coaxial motor inside, with bolts fastening it in.

http://www.cyclone-tw.com/Coaxial.html
See tabs for fastening here:
https://endless-sphere.com/forums/download/file.php?id=228169
Right side.
https://i.imgur.com/cnF0SOI.jpg
 
You’re not the only one.
My start.
 

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I could use an off the shelf kit, but then what would I do with the cool Cycloidal Drive I'm drawing?
4FRnrNI.png

But I am legitimately hoping I can make something more compact and neater than the off the shelf kits.

@Skaiwerd do you have a thread on the build yet? Any more pictures of how you're joining it to the cranks/chain?

Cheers,
Tom.
 
Tom

Thanks for asking.
No thread yet. At the figuring out how part. I have a new fork, a steel hardtail frame is on order. What’s in the picture is a 3d printed part. Mostly a test for the pulleys and jackshaft distance etc. I would like to put the motor in the frame. I was going to share the rear cassette with the motor and pedaling chains then realized I’d be peddling always when under motor power unless I gave the rear wheel drive sprocket it’s own independence freewheel, not easy I figured. So I’m thinking to go to the opposite side using a disc brake rotor adaptor. This keeps the 1x11 gearing of the mountain bike untouched and does not utilize the front crank or bottom bracket like some mid drives do. So you can use modern gearing etc. this is a big plus to me those two things.
 
Where I’m at now.
I used chopsticks as I haven’t measured for bolt length yet so loose fit. 69 hours of 3d printing for this. The main part was 50 hours, my longest print so far. About 9 ish hours each for the tube clamps. All printed with a solid 100% infill for strength.
 
Skaiwerd said:
Where I’m at now.
I used chopsticks as I haven’t measured for bolt length yet so loose fit. 69 hours of 3d printing for this. The main part was 50 hours, my longest print so far. About 9 ish hours each for the tube clamps. All printed with a solid 100% infill for strength.

I get it-- you use the tool you understand. But using filament 3D printing for this particular job? I mean, why not Pla-doh? Or pizza dough for that matter?

You can't print metal, but it's the right material for some things. Worth it.
 
i think a 3-D print with steel inlay would be nice. I am experimenting ATM with nylon prints that have a cavity inside that i fill with lazered stainless steel during printing

anyway, for a motor i think that the most feasible way is still just fastening it with some lazered bracket and the bottom bracket cups. Some lazered parts that anyone can order online from the favorite lazer shop arent expensive

what material do you use? PLA? Can you be so kind and give us some dimensions of the motor? Did you measure the weight?
did you print the larger belt pulley, too? Looks nice!
 
Yes it’s a qs motors qs1000 mid motor.

Crossbreak
I can provide measurements and the weight soon. I’ve pondered the inlay of metal with my designs and while printing. I’ve thickened my printing and go solid 100%. I will post a screen shot of the cad art soon. I only use PTEG filament.
 
You're one of the first on this forum to use that motor. I'll be very curious to see your impressions if it. Are you using their controller as well?
 
The measurements of this motor the Qs1000w mid motor. I’m going to use a necular controller 12f probably at 75 volts. Going to do a second 3d print of the main part any day. It has minor tweaks. Still don’t know the weight it is heavy, but appears to be high quality.
 

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Comes in at just under 11lbs. You have to travel to find a scale these days.-
 

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Hey Skaiwerd,

I'm starting a build with the same combo, qs1000 with nuclear. Have you received your controller yet? I've been on the wait list for ever. Thanks for telling us the weight of the motor is I couldn't find it anywhere. Have you determined what kv the motor is yet? It looks like you bought the whole assembly and are re-purposing the pulleys? I'm going to make an adaptor for an 219 sprocket. I would like to do a single stage reduction through the bike cranks, I'm hoping 10:1 reduction is good enough on 60v. This motor should be good at 4kw, right?
 
Skaiwerd said:
Where I’m at now.
image.jpeg

Like it! Just a thought, would the motor fit to the rear of the seat tube in the 'v' formed with the seat stays? If so, what wheel and what tyre would be max possible, like 26x2.5"?
 
Larsb
I’ll try some test fitting with frames I have laying around and the motor. Above the seat stays is also an option. On long cruiser bikes you also have behind the seat tube but down low and inside the frame. I’m shooting for larger 27.5” x 3” tire on this ride but I’ll check for you smaller wheel fit.

Devo1223
I didn’t get the entire swingarm kit. Seemed like most of it would not be used, only good thing is the rear pulley and that is only a maybe on usable. Yes I’m also on the waiting list for the controller. Hope it ships in April. The Russian crew claim 3kw to 5kw from these motors with temps monitored and prob also peak numbers. 2000w-4000w should be ideal/dream motor combo from this. I’m going for more like 13:1 ratio using electric scooter parts calculator.
 
Grantmac said:
How is the drag turning the motor over by hand? I'm contemplating a non freewheeling drive at the moment.

Turning it by hand will let you know about cogging, but cogging isn't nearly as big a source of loss as eddy currents at operational RPMs. Turning by hand tells you nothing about eddy current losses, because it isn't fast enough.
 
Grantmac

Spins fairly easily. More resistance turning very slow but not much if you spin anything above the slowest. I’ve thought of this also with this motor. In my mind it would have to be left side drive, zero free wheels and preferable single stage reduction right? The point is for regenerative braking right? And simplicity? Skip the pedals for the Moto version or not as the pedal power is on the usual side, right side.
 
Yes, planning a left side drive with the right side for pedaling. Just one reduction stage likely 219 and using regen because we have long hills.

If I absolutely need to pedal I can remove the left chain. I'm more interested in a useful cruising cadence and reduced wear on the cassette.
 
ok I just bought my qs 1000w. Let's start a new thread

https://endless-sphere.com/forums/viewtopic.php?f=28&t=99554
 
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