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

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

Post by Solaire » Jun 13 2018 8:33pm

+1 megaionlaunch

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

Post by tangentdave » Jun 13 2018 9:08pm

Was thinking gnarly trail. You guys and your drag races. Which, by the way, has been one of the events.
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Re: Dave's 80:1 RC mid drive kit build log

Post by morati » Jun 14 2018 6:49pm

"I'll have a new build, keep up if you can."
Look forward to seeing the new rig......

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

Post by devo1223 » Jun 15 2018 11:25am

Yeah gnarly trails would be cool. 50mph double track is fun and all, but maybe some log crossings, rock garden? When you headed down? Their flyer says camping starts June 29th. I guess those guys will be out there for a week. I could come the weekend before to help trail build for a bit.
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Re: Dave's 80:1 RC mid drive kit build log

Post by morati » Jun 15 2018 2:25pm

Anyone using the newer SRAM EX-1 drivetrain yet on their Tangents? Thought I might try this out on mine with a new Onyx hub as I am having some grinding/skipping issues on my 3210 equipped bike.

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

Post by tangentdave » Jun 15 2018 2:53pm

I'll arrive a couple days early, exact date TBD. I'm camping out, the ranch is awesome. There's running water and electricity and all that jazz. Shower and a lake nearby. Downieville and Mills Peak are a quick drive from the ranch, we're talking about getting a group together for a ride or three, all are welcome. I also would like a race with a good mix of gnar, technical, hill climb and speed sections; like a real moto enduro.

I have an EX-1, it works just like a normal cassette. 48t-11t with 8 speeds means not much overlap between the gears, which is great for the motor. The first 4 gears are about 10mph apart (under motor power), works great. Derailleur is easy to adjust and seems to hold the tune. The largest cog is riveted to the next 4 which are machined from a single billet. For ebike use, the SRAM XD driver is better than the standard Shimano splined freehub, even in you're not using a 10t cog (the cassette doesn't dig into the freehub with the XD driver).

New batch of engines is arriving next week, one of them is mine for this race. Will post deets on the new build (or maybe you'll have to come out to the event to see what's cooking...)
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Re: Dave's 80:1 RC mid drive kit build log

Post by DolphLundgren » Jun 16 2018 4:39pm

tangentdave wrote:
Jun 15 2018 2:53pm
I have an EX-1, it works just like a normal cassette. 48t-11t with 8 speeds means not much overlap between the gears, which is great for the motor. The first 4 gears are about 10mph apart (under motor power), works great. Derailleur is easy to adjust and seems to hold the tune. The largest cog is riveted to the next 4 which are machined from a single billet. For ebike use, the SRAM XD driver is better than the standard Shimano splined freehub, even in you're not using a 10t cog (the cassette doesn't dig into the freehub with the XD driver).
As far as I know there is no EX1 cassette for XD drivers available yet.

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

Post by Ham » Jun 18 2018 8:01am

Been a while...melted my power cables through from the battery bag to the under saddle connection!

Can someone remind me what gauge cable I need for the 3220 set up please?
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Re: Dave's 80:1 RC mid drive kit build log

Post by tangentdave » Jun 18 2018 11:18am

Welding that rear tire to the dirt. jeezus, that's a lot of electrons.

8 gauge will work well, use a type of wire called 'oxygen free copper' (OFC). Car audio stores usually carry spools of the stuff. 5.5mm bullets for the motor, XT90 elsewhere. Obviously you'll want to make sure you have good solder connections.
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Re: Dave's 80:1 RC mid drive kit build log

Post by totolito » Jun 19 2018 4:29am

Hello everybody!

I have some difficulty with the half throttle provided witht the tangent. I'm looking for a thumb accelerator, but I'm not sure to have enough space on my right side because of the shifter, maybe I should to install it on the left side.

Do you have any feedback with this type of throttle? Is it not so disturbing to have it on the left side?

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

Post by totolito » Jun 19 2018 4:29am

Hello everybody!

I have some difficulty with the half throttle provided witht the tangent. I'm looking for a thumb accelerator, but I'm not sure to have enough space on my right side because of the shifter, maybe I should to install it on the left side.

Do you have any feedback with this type of throttle? Is it not so disturbing to have it on the left side?

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

Post by Ham » Jun 19 2018 7:27am

tangentdave wrote:
Jun 18 2018 11:18am
Welding that rear tire to the dirt. jeezus, that's a lot of electrons.

8 gauge will work well, use a type of wire called 'oxygen free copper' (OFC). Car audio stores usually carry spools of the stuff. 5.5mm bullets for the motor, XT90 elsewhere. Obviously you'll want to make sure you have good solder connections.
Thanks Dave,

I'll get someone else to do the soldering for me:)

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

Post by tangentdave » Jun 19 2018 12:34pm

8ga standard cable: 0.63ohm per 1000ft
Tangent cable: 4ft (0.63/250= 0.00252ohm)
100A cable heating: (100A)*(100A)*(.00252)= 25W
50A cable heating: (50A)*(50A)*(.00252)= 6W

Screen Shot 2018-06-19 at 10.31.31 AM.png
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Consider the whole vehicle. 6ga or 4ga cable doesn't gain us much and weighs a bunch more.



Totolito, you can use the half twist on the left side (although you'll have to rotate the grip forward for throttle). There are left hand thumb throttle available, Grin has one that is plug and play http://www.ebikes.ca/shop/electric-bicy ... ttles.html). I myself am not a fan of thumb throttles, but to each their own.
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Re: Dave's 80:1 RC mid drive kit build log

Post by ferret » Jun 19 2018 2:51pm

totolito wrote:
Jun 19 2018 4:29am
Hello everybody!

I have some difficulty with the half throttle provided witht the tangent. I'm looking for a thumb accelerator, but I'm not sure to have enough space on my right side because of the shifter, maybe I should to install it on the left side.

Do you have any feedback with this type of throttle? Is it not so disturbing to have it on the left side?
I use WUXING 108X, on the left side.
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After running it stock for some time, I shortened the lever with a grinder to get less throw and more sensitivity.
Happy with it.

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

Post by totolito » Jun 20 2018 2:41am

Thanks men!

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

Post by Ham » Jun 23 2018 5:42am

tangentdave wrote:
Jun 19 2018 12:34pm
8ga standard cable: 0.63ohm per 1000ft
Tangent cable: 4ft (0.63/250= 0.00252ohm)
100A cable heating: (100A)*(100A)*(.00252)= 25W
50A cable heating: (50A)*(50A)*(.00252)= 6W


Screen Shot 2018-06-19 at 10.31.31 AM.png


Consider the whole vehicle. 6ga or 4ga cable doesn't gain us much and weighs a bunch more.



Totolito, you can use the half twist on the left side (although you'll have to rotate the grip forward for throttle). There are left hand thumb throttle available, Grin has one that is plug and play http://www.ebikes.ca/shop/electric-bicy ... ttles.html). I myself am not a fan of thumb throttles, but to each their own.

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

Post by Mugenski » Jun 23 2018 1:30pm

In Canada I can find weldering torch cable pretty cheap at princess auto. If in the US maybe harbour freight has something similar. Otherwise maybe a welding supplier can hook you up. I find anything audio related to be very overpriced. I'm running 8 at the moment but I do notice warm cables when the weather is cooler.

In other news I have my kit apart for the upgrade and I am really surprised how small the astro is. Always thought it was bigger than it is. Small but heavy that is for sure. The gen1 has been through a kerosene wash and will take up desktop tinker toy duty from here on out :D
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Re: Dave's 80:1 RC mid drive kit build log

Post by tangentdave » 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.
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Re: Dave's 80:1 RC mid drive kit build log

Post by morati » Jul 02 2018 11:35am

I know this topic has been visited before but just wondering if anyone has made some headway to fitting a better crankset to Dave's drive system?
Pages 12 through 16 for more info on the Rcoky Mountain/Raceface sprag clutch setup....
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Re: Dave's 80:1 RC mid drive kit build log

Post by tangentdave » Jul 02 2018 1:02pm

That is a clean crankset setup. If I'm reading this correctly, Rocky Mountain seems to have made their own sprag bearing that fits onto the RaceFace splines on the crank, secured with a special locking ring:
Screen Shot 2018-07-02 at 10.57.48 AM.png
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Re: Dave's 80:1 RC mid drive kit build log

Post by morati » Jul 02 2018 1:12pm

Correct Dave! That is a numbered part and available directly through Rocky Mountain dealers. My wife has one of these bikes and I can attest to its smoothness and functionality. It'd look great on one of your setups!

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

Post by tangentdave » Jul 02 2018 2:15pm

2018 Lost Sierra build


20180628_151244.jpg
Guerrilla Gravity MegaTrail (hand made in Colorado)
MRP Ribbon fork, 170mm (made in Colorado)
SRAM Guide RS stoppers, 203mm Ice Tech rotors (purposefully incompatible SRAM/Shimano standards be damned)
RockShox Super Deluxe rear shock
DT Swiss M1700 wheelset, Maxxis Minion DHF 2.8" front, Minion DHR 2.5" rear
SRAM EX1 48t-11t cassette, 8 speed w/ EX1 ebike chain
SRAM steel Xsync 30t chainrings (motor+derailleur)
OneUp 150mm dropper post
42lbs, ready to ride
20180628_154630.jpg
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Hardened steel cassette, steel chainrings, ebike chain, Ti-nitride coated motor chain (cause it makes me faster)

20180628_172304.jpg

Drive unit weight: 7.5lbs
Dimensions: 100mm diameter, 120mm length
Engine: Neutronics 3215, 225kV
Controller: Castle Talon 120, custom mount/heatsink, QS-8 main battery connect
Performance (calculated w/ 120A phase):
135ft-lbs crankset torque
400RPM crankset
48t cog: 216ft-lbs wheel torque, 21mph
42t cog: 189ft-lbs wheel torque, 24mph
32t cog: 144ft-lbs wheel torque, 31mph (straight chainline)
24t cog: 108ft-lbs wheel torque, 41mph
18t cog: 81ft-lbs wheel torque, 56mph


This drive is easily removed from the frame in only a few minutes, turning the bike into a 34lb enduro beast. A custom mounting bracket matches the lines of the frame and shows no flex under a full 8kW load. The freewheel crankset can remain in place or is quickly swapped with a standard crank arm for another 1lb of weight savings. The CA remains tucked behind the handlebars, the Domino is exchanged for a normal lock-on grip.

20180628_165924.jpg
20180628_165936.jpg

Why a removable motor unit? So I can race Cascadia enduro events one weekend, plug the motor in, race Lost Sierra the next, pull the motor and ride the Downieville DH course same day. This bike is capable of competing in absolutely punishing Enduro World Series events and hang with the motos in OHV areas. One bike, any trail.

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Come out, let's ride bikes!
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Re: Dave's 80:1 RC mid drive kit build log

Post by devo1223 » Jul 02 2018 3:33pm

Nice build Dave, could I ask you a favor and bring an extra set of those QS-8 connectors to buy off you? I'm over xt-90s and 8g wire, what a pain. Finally got mine ready to race. Low budget tech vs cutting edge, may the best machine win!
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Re: Dave's 80:1 RC mid drive kit build log

Post by tangentdave » Jul 02 2018 4:14pm

Nice! I like the darked out look, it's mean. And yes to the dual crown forks. I see hubsinks on the motor, Statorade as well? It'll be a battle of as much copper as possible vs as little as possible. Advantages to both.

There's a ton of riding to be done at the ranch. It'll be a fun time, this trail race I'm stoked on is only a part of the weekend. Chris's ranch has hundreds of acres of all type of riding, from mild to wild. He hosts ebike and atv tours so he's pretty good at this. Like a Sea Otter Classic for ebike nerds. There will be several other builders as well- Bjorn Enga with Kranked, Derek with HPC, JP LaMere, Kevin Risse and hopefully some fast guys coming from Luna, according to Chris.
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Re: Dave's 80:1 RC mid drive kit build log

Post by morati » Jul 02 2018 4:56pm

Nicest build to date Dave! Wish I could be there but only this week left for vacation + I think Canada/USA is about to build a polite hedge between our countries to keep us separated, lol! Let us know what you think of the Neu motor. I've owned several for R/C applications and found them to be quality units. Good luck to all at the race!

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