My attempt at a lightweight EMTB with torque based PAS

[andrea_104kg]

the problem with the freewheel is that to make it work, I have to mount it upside down, with the writing inside. If mounted in the right direction the ring tightens well but does not work for a central motor. Vert strange for a freewheel of a central motor. Is it the same for you?
the jobike forum is a very old forum, on electric bikes you can find everything but you have to go back over the years. Try searching for 'barbamotore' in the search field.

 

[Sandguppy]

So Im redoing this thread, too messy in last attempt....

Ive lately starting to get interested in single trail riding, and have 2 bikes equipped with tsdz2 motors. One fatbike for the easy rides, and one full suspension Liteville for going up the steep stuff, and trying to get back down without breaking stuff. I mostly use the FS bike in the summer. I like pedaling (well, sort of. I need the exercise, and I get lazy if I have a throttle), so I enjoy the torque sensored lightweight tsdz2. That is, until they started breaking. The spindle broke on the fatbike, and the tsdz2 on the FS bike let out the magic snoke at 982km. There's been some other small bugs with the tsdz2's also, enough for me that I want to move on to something else. Ive learned so much from this page, so I want to make a build thread, in case someone else is looking for something like this.

The easy solution is to buy a commercial emtb, PaulID's excellent kit, or wait and see how the lightest.bike kit will be, but knowing myself, I will never stop customize the bike, so Id rather put something together myself.

Build goals:
- Mid drive
- lightweight (sub 20kg on the FS bike)
- torque sensored
- 6-700w peak power

First problem is finding a solution for the torque sensor. The power from the motor must not affect the sensor, and I need a freewheel. Luckily, the CYC X1 kit has this, and parts are readily available in their webshop. So I got one for the FS bike.

I will use a cycle analyst to process the torque sensor signals and display information.

Very interesting builds, thanks for documenting

How are your builds holding up?

 

[HrKlev]

Thanks! They are holding up quite good. I've replaced the freewheel on the fatty 2 times, but apart from that, only normal bike-stuff that needs fixing. They are only used for tecnical single trail, so maintenance is quite high and mileage low compared to road-use, but they have reached around 1000km each so far (plus another 980 with the tsdz2 kit).

I dont know why the freewheel holds up fine on the FS bike, but keeps breaking on the fattie, but I see that CYC has come up with a much sturdier one now. Will order that next time.

 

[Sandguppy]

Thanks! They are holding up quite good. I've replaced the freewheel on the fatty 2 times, but apart from that, only normal bike-stuff that needs fixing. They are only used for tecnical single trail, so maintenance is quite high and mileage low compared to road-use, but they have reached around 1000km each so far (plus another 980 with the tsdz2 kit).

I dont know why the freewheel holds up fine on the FS bike, but keeps breaking on the fattie, but I see that CYC has come up with a much sturdier one now. Will order that next time.

Perhaps the FS bike has a softer power application? Like a cush hub on a motorcycle.

I have most of the parts for my first build. Using a similar drive train design as you.

 

[Ham]

Hey Guys,

Just in the process of soldering up the jst from the cyc torque sensor to cycle analyst and matched all the wires (red to white, black to black, white to green), the final one I just need to double check:

green rotation signal from torque sensor to...? Thinking it needs to be CA3 blue (DIR) but wasn't sure it isn't Yellow (rpm) on the CA3...any sugestions?

Thanks

 

[Ham]

OK went with yellow for rpm.

Can anyone here share the ca3 pas settings for this torque sensor, struggling to get it give a motor response at all.

Also any help with the proper placement for the resistor on the domino?

Thanks

 

[HrKlev]

OK went with yellow for rpm.

Can anyone here share the ca3 pas settings for this torque sensor, struggling to get it give a motor response at all.

Also any help with the proper placement for the resistor on the domino?

Thanks

Sorry, didnt notice the replies to the thread, I havent had too much time for ES lately.
On my setup (dont know if any of the colors have changed lately):
RPM from Torque sensor is green, connected to Cycle analyst yellow
Torque signal from torque sensor is white, connected to Cycle Analyst green.

I will try to remember getting the settings from my CA after work today. Lost the setup files in a PC crash a couple weeks ago.

 

[Ham]

Thank you,

I think I have it figured out to some level now as both the torque sensor and domino work on the bench.

I am currently trying to understand the microswitch in the throttle and if/how it can be beneficial to me in some way

 

[szkuba]

....
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.....

really clever idea In regards to pinion is it supported by two bearings in order to keep up with the side loads on the axle? Also while the hub shell does not rotate i think it is possible now to improve heat dissipation by applying termal pads between motor and the shell ??

 

[neptronix]

Very cool build, dude

 

[brazilianboy]

Its been a little back and forth with motors on this bike, but when the tsdz2 burned, I needed to put something together on the FS bike again. I already had a torque sensor and freewheel from the CYC X1, a cycle analyst, and a MY1018 brushed motor. So I converted a bracket to fix the motor to the frame.

View attachment 278885

Here's the torque sensor and freewheel. I used an old chainring from a cyclone kit to make an adapter from whatever BCD the freewheel is to 104bcd, and attached a 32T and 44T chainring to it

View attachment 278886View attachment 278887

The 44T was later replaced with a 48T. After a lot of tweaking with the cycle analyst the bike behaves quite good now. But, the MY1018 is very loud, and not very efficient when it is not in the peak powerband... The tsdz2 got me a lot longer on the same battery. Doing drops and jumps without fearing that the spindle would break was awesome, though! The added ground clearance is also a very welcoming change.

View attachment 278888

The bike now weights 20.2 kg, so not too bad. The MY1018 must go, though. I have decided to go with a small, geared hub motor that will be mounted as a mid drive, and a baserunner controller. The baserunner has a unique(?) feature to simulate an electric freewheel for use in the clutchless GMAC. I think this will work very nice to keep the motor running and keeping tension in the driveline when not pedaling, so I get instant reaction without the jerk that happens when the motor catches up with the driveline. I have also ordered a Bafang G310 (2.5kg and a AKM/cute XS75 (1.4kg). If the XS75 is powerful enough, I will use it for the FS bike, and the Bafang for the fatbike. Because of reasons, the completition of orders and shipping takes forever, though, and in the meantime Im grinding away on the MY1018.

The freewheel go directly on the top of the torque sensor without any kind adapter or maching?