Dave's 80:1 RC mid drive kit build log

Dave was able to send out my kit for fitting while waiting for my Astro 3215. I had a chance to tinker with it over the weekend. Everything looks top notch.
I think I would be afraid my drive train on the niner would not survive a 3220, so I'm hoping 3215 is the sweet spot for me. 22t motor to 32t crank, then 36t to the cassette(15t-40t).
 

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I've been having trouble with the amount of friction between the plastic chain tensioner and the chain in deep mud. So, I'm calling this idea the tension wheel.

tension wheel.jpg
This is a 3d printed (for now) roller wheel that captures two sealed bearings inside, mounts on a simple shoulder screw. The wheel is printed out of Ninjaflex and gives us both a ball bearing roller and proper motor chain tension.

wheel bike.jpg
The shoulder screw is mounted through a slot in the plate and pushed just slightly into the chain. The compression of the wheel keeps the motor chain tensioned without adding any perceptible resistance. Simple. Bombproof. All the kits going forward will use this and anybody with the plastic flipper is getting an upgrade.


-dave
 
Nah, the chain in the pic is the same chain I've been using. We do need to unbolt the roller to get the motor chain on and off, slightly more difficult than just pushing the flipper.

I should have a big batch of black parts back from the anodizing shop this week or early next. Time to find another anodizing shop that meets their deadlines (supposed to take 6 days, we are now at 30 and counting), sorry it's taking them so long, they do do nice work. A bunch of stuff is going out to you guys ASAP. I'm honing in on the processes and things will start moving faster.


-dave
 
tangentdave said:
I'm calling this idea the tension wheel.
Click to expand...

Oh, this is sweet!
 
What kind of longevity do you think is possible for this smart tensioner? I liked the idea of it being made with ball bearing rollers. So spin freely, yes?
I think the other chain tensioner I've seen have been either metal ones with teeth for chain or ones made from inline skate wheels. Your material looks more sturdy yet with low friction or drag.
 
The longevity is my only concern at this point too. I have about 20 miles on mine with no wear. The stuff its made of is pretty tough and this whole piece is cheap and easy to make. The slot is long enough to be able to take the chain slack up with just the bolt and bearings, so it shouldn't leave you stranded if the wheel gets ripped off. I don't need to compress the roller wheel hardly at all to keep the chain tight (I can't even see any compression) so I bet the give will extend it's life compared to a hard roller since the chain won't dig in due to too much tension.

The slot is sized for an M6 bolt to pass thru, so there are lots of other options we could pursue if the tension wheel becomes troublesome.
 
This seems as good a good alternatives as the ones I mentioned. Sure there could be others I am not aware of, but those inline wheels are soft compound material and the chain will take its toll on those. Keep beating on your test ride and let us know how it holds up. Anyway it seems like a quick fix to replace so should be effortless to swap.
 
A few reasons. Why have two parts per side when we can use one. The hinge is a point of weakness and the mount will flex there. BB's are never perfectly perpendicular so there will be some wobble in the crankset on most frames (not to mention the ISIS BB). The only way to really get rid of that chain snap is with some sort of spring (chain snap eats aluminum sprockets and bicycle chains). If there were a hinge in the middle of the mount I couldn't use that space for the speed controller.

Spring tensioners make things feel so much nicer, in my opinion. And a one-piece mount plate can be very sturdy and is easier to make than two mount plates. This tension wheel thing takes me 10 seconds to assemble and install so it's no trouble at all.
 
Hi, im also interesting about TQ sensing. Do you know about some TQ sensing BB? Im very interesting in this kit but TQ sensing is crucial for me. I have two heavy modified bikes with bosch performance mid motor a once you try TQ sensing there is no way back. Cycle analyst can be configured for this IMO. But i dont know how much you can configure it. Bosch use quite complicate management /i try to reverse engineer it/ It not only sense torque but also looking for "pulse" in signal from which it determine cadence and also use acceleration and inclination sensor to further optimize support. Do somebody tried configure CA for TQ sensing?

many thanks
 
The CA is designed for a PAS/THUN input, so yes, we can use those throttle methods with this kit. I haven't tried this, I'm personally prefer a twist throttle. This BB
http://www.ebikes.ca/shop/ebike-parts/torque-sensors/thun-128l.html is probably a good choice to try and except for the square taper cranks is a direct swap for the 68/73mm BB I'm using now. There are other threads detailing setting up a THUN+CA, so that should be quick.


-dave
 
tangentdave said:
The CA is designed for a PAS/THUN input, so yes, we can use those throttle methods with this kit. I haven't tried this, I'm personally prefer a twist throttle. This BB
http://www.ebikes.ca/shop/ebike-parts/torque-sensors/thun-128l.html is probably a good choice to try and except for the square taper cranks is a direct swap for the 68/73mm BB I'm using now. There are other threads detailing setting up a THUN+CA, so that should be quick.


-dave
Click to expand...


Can the freewheel on the crank side be attached to a square taper BB? How does the attachment work? Does it require ISIS?
 
The freewheel is mounted on threaded cranks. The threaded cranks are mounted to the BB spindle. Both ISIS and square taper threaded cranks are readily available so we can use either square taper or ISIS BB's.
 
tangentdave said:
The freewheel is mounted on threaded cranks. The threaded cranks are mounted to the BB spindle. Both ISIS and square taper threaded cranks are readily available so we can use either square taper or ISIS BB's.
Click to expand...

That's pretty good then, I could use one of Ebikes.ca torque-sensing BBs and wire it to the CA for PAS. Ebikes.ca sells an ISIS torque-sensing BB as well but it's more than twice the price of the square taper.

Can a BAFANG (or whoever makes it) left thumb throttle be used instead of the Domino? This one:

left-thumb-throttle-500x500.jpg
 
Got a few weeks of urban shredding in on the new kit, noting to complain about.
Everything is tight and stiff, acceleration is awesome!
INTENSE Tracer275a 160mm travel
CaneCreek DoubleBarrel-INLINE rear shock.
RockShox Lyric180mm fork
ENVE M60/forty carbon wheels with DT 240s hubs.
ShimanoXT brakes with IceTech rotors and pads.
Thompson dropper post (not shown)
XO DH derailleur, X9 shifter.
Maxis HighRoller tires, tubeless.
Sensus grips, StraitlineAMP stem, Deity composite pedals.
Tangent 3210
39lbs complete as shown!
(backpack battery extra)

Epic customer service! answered a bazillion questions....planning another...
DSC_0009.jpgView attachment 1DSC_0011.jpg
 
\m/ :lol: \m/

thanky much!
When the weather dries out the trails...I'm gonna flood ya'll with ripping vids.
 
lightrush said:
Can a BAFANG (or whoever makes it) left thumb throttle be used instead of the Domino?
Click to expand...
The standard kit uses a CA to process the throttle signal, so just like with torque sensing, you can use anything the CA supports.
 
So from what I gather this kit should be easily convertible to torque PAS. And since it's small, one can even tackle the noise with some makeshift semi-open enclosure, if needed. I think I'm going to pull the trigger in the coming months. It's a bigger investment than BBS02, but the latter is also a large investment so might as well get the right thing from the get go than being sorry down the road.
 
Leebolectric said:
Got a few weeks of urban shredding in on the new kit, noting to complain about.
Everything is tight and stiff, acceleration is awesome!
INTENSE Tracer275a 160mm travel
CaneCreek DoubleBarrel-INLINE rear shock.
RockShox Lyric180mm fork
ENVE M60/forty carbon wheels with DT 240s hubs.
ShimanoXT brakes with IceTech rotors and pads.
Thompson dropper post (not shown)
XO DH derailleur, X9 shifter.
Maxis HighRoller tires, tubeless.
Sensus grips, StraitlineAMP stem, Deity composite pedals.
Tangent 3210
39lbs complete as shown!
(backpack battery extra)

Epic customer service! answered a bazillion questions....planning another...
View attachment 2View attachment 1
Click to expand...

Quick question: my frame is very similar to yours - my rear brake and dérailleur cable are on the top of the down tube exactly like yours. How did you avoid crushing the cables where the motor sits on the down tube or does it not put pressure on them?

EDIT - did you just route them round it? I can't tell from the photos?
 
Dave,

To help us with gearing properly, do you have a number for stock RPM or cadence at 100% throttle?
 
The cables go through the mounting plates, then curve upwards to the seatstays.
It's a tight bend, but no ghost shifting or pinches yet.
Next time I service it...I will reroute the cables along the top tube for a cleaner run.

Website says max cadence 140, it's like fast disco spinning in granny gear...my legs can keep up, barely.

 
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