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

Discussions related to motors other than hub motors.
This includes R/C motors, botttom bracket, roller and geared drives.
DolphLundgren   10 mW

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

Post by DolphLundgren » Jul 22 2018 10:10am

thx @aCeMadMod!
How much Power? On your Cyclone or on your 3220? How many miles aprox.?

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

Post by Hillhater » Jul 23 2018 2:05am

is the TQ 120 drive using the same reduction system as the Tangent drive ?
TQ call it " Harmonic Pin Ring" ( HPR) technology, but it sure looks to be similar.
I believe they say it is a 37:1 reduction giving 120 Nm of torque...but presumably low power.
which is also the same 750 W motor as used on the Eprodigy bikes ?
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tangentdave   1 kW

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

Post by tangentdave » Jul 23 2018 5:26pm

The Tangent gearbox and the TQ unit are both eccentric, but that's about where the similarity ends. I saw another video of the unit, this was advertising the M1 Spitthing ebike, it showed how they're using a ring of pins and an eccentric gear with a special profile that looks more like a chainring than an internal gear.
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Animalector   10 kW

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

Post by Animalector » Jul 23 2018 7:02pm

well it's funny but when i first asked the question, before I saw that you tube video, it was actually the sound of the drive that first got me thinking about the similarity between tangent and TQ..

Anyway, it is nice to see various solutions to the reduction problem, all with great success.

Andy

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tangentdave   1 kW

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

Post by tangentdave » Jul 23 2018 8:28pm

Found it. A wobble disc full of pins gets pushed/pulled in/out of the ring and eccentric gears.





Screen Shot 2018-07-23 at 6.24.06 PM.png
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Mugenski   1 W

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

Post by Mugenski » Jul 25 2018 7:05pm

Fellow tangent users, I am experiencing a drive chain issue with my Gen1.5 kit and I am wondering if anyone can offer some advice.

I installed the upgraded kit and have now been plagued with a drive chain skipping/popping. The drive chain under moderate load (2kw) tends to fail to seat properly on the chainring. I have tweaked the alignment and it looks spot on to me. I have also tried 2 different chainrings and 2 different chains. Tried adjusting the tensioner to no avail. I can watch the tensioner take load when the chain fails to seat properly and then it all seems to snap into place as the slack is removed from the chain. From what I figure the chain is riding on the tops of the teeth but not bad enough to be thrown entirely. If I move the chainring outboard anymore I will be going against what looks to be the perfect chainline from motor to spider.

Anyone had this issue or have any ideas? I am going to go push the chainring/spider out even further and cross my fingers.

Edit: Okay I took some sketchy video, looks like the chain is indeed failing to seat properly and occasionally riding up. I have tried with the spider shifted (via moving the bb cups) both in and outbound to the limits and the problem still remains. It looks like the wobbly freewheel may be causing the issue. I had noticed the wobble with the G1 but it never caused any issues. On the upgraded kit it is the only thing I can pin the issue on. Spinning the cranks in reverse the wobble seems to be about 1mm. I'm guessing under load it is more pronounced and causing the skipping.

Question is what freewheel do I switch to?
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tangentdave   1 kW

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

Post by tangentdave » Jul 25 2018 11:52pm

The Cyclone FW from SickBikeParts is prob the best for high power mid drives. Are you experiencing a left/right wobble?

Double check the chainrings-- make sure the chainring bolts are cinching the rings against the spider. The long nuts should not stick past the second FW so the bolts are able to cinch the rings against the spider (rather than bottoming out on the nuts before the rings are held tight).

It might be easier to watch the skip while the bike is on a stand- spin the wheel and apply some rear brake for load.
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knurf   1 W

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

Post by knurf » Jul 26 2018 2:49am

I’ve had my share of chain skipping. For me it’s always either worn chains and/or worn chain rings. Throw out worn chains and use fresh ones.. they are only good for 1500km at most, probably around 1000km is more realistic.
I’ve also had trouble with a overly tightened tensioner (the gen 1 soft wheel thing). Running it fairly loose and using fresh chains with nice narrow wide chain rings has solved most problems for me.

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

Post by Ham » Jul 26 2018 5:42am

tangentdave wrote:
Jun 23 2018 3:34pm
Oh, ha, I didn't even answer his question. Ham, also look at car audio shops, they use lots of large diameter OFC cable. They'll also use another kind of cable called copper clad aluminum (CCA). Both will work for us, OFC is better but by how much is up in the air. OFC will be 3x heavier, CCA will have slightly higher resistance. Your first set of cables were CCA. You didn't really melt the wire insulation, did you? That's hard to melt with a soldering iron.

Also, ebay is a wealth of such items.
So i have only just a) seen this and b) got back to fixing up the bike.

yes Dave, melted clean through the power cable and outer casing..I'll drop you the pic via email.

The local audio shop has OFC in 8ga but said it would likely melt again with 100amp+ peaks and to try household oven cable rated at 240v and 60 amps continuous....sounds nuts to me but i know zilch about electronics!

Seems Hobby King have stopped offering xt90 connector blocks too...
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Re: Dave's 80:1 RC mid drive kit build log

Post by Clyon2 » Jul 26 2018 8:41am

I also had drive chain skips. Alignment is critical. Couple millimeters counts, especially with a narrow wide chain ring and the short chain run. Free wheel wobble makes it worse. A bit of flex under power makes it worse.
My best solution so far is Surly stainless chain ring. No slips/skips at all. No chain drops. We will see how it wears.

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

Post by tangentdave » Jul 26 2018 3:20pm

It's possible a narrow-wide receiving ring at the crankset is a bad idea.
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Mugenski   1 W

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

Post by Mugenski » Jul 26 2018 3:41pm

I've tried aluminum narrow-wide as receiver. I'm now on to a fleabay steel receiver. I've tried everything with position of the rings and different chain tensioner settings. No es bueno.

Getting progressively sweatier in the garage and running out of options I decided to remove the tension aspect of the tensioner. I shimmed it with washers and tightened it so that it could move if the chain skipped hard but otherwise it should stay put. In quick testing between rain clouds the issue has seemingly gone away. Looking at the tensioner there is some play in it left to right and it's ever so slightly off kilter. I'm guessing with load applied it swings outboard and shimmies the chain off the ring just enough to cause the pop.

I will have to test more in better weather and find the best way to secure the tensioner. I don't think I'll be able to get the play out of it enough so that I can use it with the spring. The only thing I didn't try was adding a couple more links to the chain. It's possible that may help. The length I am currently using is just enough to get the chain on and off without a master link - the same way I had my G1 setup.
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Solaire   1 mW

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

Post by Solaire » Jul 26 2018 4:44pm

For chainring position, i measured from inside of mounting plate to center of motor freewheel teeth, getting 20.4mm and set my motor chainring also 20.4mm from inside of mounting plate in the middle of the wobble( i put 2 X 1mm spacers between the plate and BB cup). I have about 1mm wobble also. That gave me a reasonably straight line from the freewheel to chainring. At that point if the pulley is out of alignment it should be obvious whether it is sticking outside of the wobble zone sending the chain off. Only use the lightest tension to minimise it being affected by spring. ALSO check to see if your derailments have bent your chain.

I used the wolftooth chainring, with a new 10s X10 kmc chain. Modern narrow wide chainrings need 10s chain. 9s wont work very well.

Good luck, derailments are so annoying.

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tangentdave   1 kW

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

Post by tangentdave » Jul 26 2018 4:55pm

Dropped chains are the worst. I purposefully put a slot in the mounting plate so we could use the old school bearing-mounted-plastic-wheel tensioner if needed. Sounds we could give that a try. Mugenski- shoot me a PM so I can remember who to send the tension wheel to.
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Re: Dave's 80:1 RC mid drive kit build log

Post by knurf » Jul 27 2018 8:33am

I’ve been running the old tensioner without a plastic wheel, directly on the metal bearing surface.. it’s loud but works fine (I’ve shot a few plastic thingies into the forest running an old chain)

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

Post by Clyon2 » Jul 28 2018 7:26am

A few thoughts:
I would be reluctant to add chain length. There is enough wrap on the sprockets for full engagement. Mote chain means sharper angles around the tensioner and a greater direction change. Minimizing sharp direction changes is always a good goal.

I am not currently having a problem, but my next move would be a larger diameter tensioner roller to minimize the amount of chain flex. The goal is to be able to install without breaking the chain with as little extra chain flopping around as possible. It might also cut noise.

I like the spring loaded tensioner. It gives tolerance for things like twigs passing through. Massive tension is not necessary so long as the chain is not climbing the teeth on the chainring.

The arm on the tensioner was bent a bit after a chain toss. Bringing it back into alignment with an adjustable wrench was not hard.

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

Post by Mugenski » Jul 28 2018 12:23pm

I'm pretty happy with the results of removing and fixing the tensioner. Took a 40km ride and only had an issue when my method of fixing the tensioner failed. Otherwise the drive performed great.

Also just finished setting up my Neptune Lite from Danny at speedict. I wanted something to log the min voltages of my cells and show me where the weak strings/groups are. I don't really have anything large enough to load these packs and check them manually so the neptune is nice to just keep an eye while riding. That said now that I know I have some weak cells I guess I need to do something about them...
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BonesNis   10 mW

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

Post by BonesNis » Jul 28 2018 4:47pm

Hey

For all those who received Dave's outstanding second gen 6KW Tangent, can you give me the cycle analyst settings for "Setup Calibration" that was installed when you received it from Dave?

Slight finger issue...lol...

Looking for the following settings:

Setup Calibration (for Hi -> Range)

- Cal -> RShunt (mOhm)
- Cal -> V Scale (V/V)

Awesome, thank you!
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tangentdave   1 kW

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

Post by tangentdave » Jul 28 2018 6:10pm

Rshunt= 1.00000mohm
Vscale can be left alone.

When switching from Hi to Low range, or vice versa, all amperage setpoints are scaled by 10 and should be double checked. Max Amps, Again, Fast Threshold and Rshunt should be checked every time the CA is changed from to hi to low or low to hi range.
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Re: Dave's 80:1 RC mid drive kit build log

Post by Ham » Aug 04 2018 11:45am

Hi Guys,

What are the shortest motor mounts anyone has used?

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

Post by tangentdave » Aug 04 2018 12:52pm

John's Airborne Plauge uses a 168mm long mount. There's not much room between the crankset and the motor freewheel for a tension device if the two centers are closer (168 from center of BB to center of motor). Perhaps a gear solution like the Paradox kit could get it closer...but chains are pretty damn robust.
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Re: Dave's 80:1 RC mid drive kit build log

Post by E1Allen » Aug 04 2018 3:48pm

So apparently my rear derailleur the

Shimano Saint Shadow Plus, RD-M820

Doesn't fit a 42t cassette. It says maximum 36t.

I tried to install the 42t with the derailleur but it hits the 42t sprocket.

You think 36t is enough torque for big hills? Or should I try another alternative?

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

Post by Mugenski » Aug 04 2018 4:01pm

E1Allen wrote:
Aug 04 2018 3:48pm
So apparently my rear derailleur the

Shimano Saint Shadow Plus, RD-M820

Doesn't fit a 42t cassette. It says maximum 36t.

I tried to install the 42t with the derailleur but it hits the 42t sprocket.

You think 36t is enough torque for big hills? Or should I try another alternative?
I used a derail hanger with success.
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Adamlivi   10 mW

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

Post by Adamlivi » Aug 04 2018 4:23pm

What’s your front ring setup? Wheel size?

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

Post by E1Allen » Aug 04 2018 5:03pm

Front is currently 36t but I'm changing to 32t when I get the tangent kit. Rear is 11-42t

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