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

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

Post by tangentdave » Jan 02, 2018 11:20 pm

20180102_140453.jpg
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Re: Dave's 80:1 RC mid drive kit build log

Post by dtx » Jan 03, 2018 3:37 am

42 not 420 guys ;) the answer to life the universe and everything not the amount of blunts I'd like to smoke today ;)

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

Post by m4k3r » Jan 03, 2018 6:25 pm

Great work Dave, never ceases to amaze!

Haven't signed on in a while (due to life) but I'm glad I did...keep doing what you do!

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

Post by morati » Jan 04, 2018 3:31 pm

New cover page on your website looks great Dave! Looking forward to more.....

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

Post by dtx » Jan 05, 2018 4:25 am

Indeed, pure e-bike porn :D

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

Post by spiros » Jan 05, 2018 4:54 am

just immagine this frame with the ascent and integrate battery inside the frame https://www.resistance-bikes.com/homepage
just about porn bikes....anyway it will be only a dream for mostly of us but It can stimulate my brain in a some kind of epilepsy status...

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

Post by totolito » Jan 05, 2018 4:56 am

Hello everybody!

Each day I have a look on the Dave's web site. I screamed with joy when I saw the new home page, but still not "pre-command" button :cry:


:arrow: I still have a pending question: is my bike compatible with the dave's drive... I have a Orbea Alma frame. My provider told me that my crankset is a bit particular: this is a "Hollowtech" crankset.

Can I still use this bike for conversion?

Have a good year!

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

Post by tangentdave » Jan 05, 2018 12:35 pm

I think we're going to see some fun bike designs soon. I like the Effigear transmission, they're layout lends itself to ebike use with 3 parallel shafts (we might be able to apply motor power to the middle shaft and run the electrics through the gearbox for the ultimate pedelec). An article in Pinkbike about a similar (same?) frame: https://www.pinkbike.com/news/the-outli ... -bike.html

'Hollowtech' is Shimano jargon, and I believe a hollowtech crankset can be either press fit or threaded. We need a BSA threaded BB to hold the mounting plates. Creating a press fit->BSA adapter is relatively simple and I will make them soon as I can (but must needs get all the new drive unit parts/process finalized and for sale again first). Look at your frame totolito, if you're BB looks like this, the kit will fit:
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The first bike with the new Tangent hardware is coming together today. I want to avoid a kickstarter situation where I've taken people's money without an example of exactly what they're getting. When the webstore opens again (this weekend/early next week), I'll be ready to produce copies of the hardware and have a known assembly/build process. The small process things take time, like yesterday I spent finalizing how the shunt will be wired. I was using the standalone shunt from Grin, but am now soldering just the bare shunt into the line so we have 8 gauge cables all the way to the battery. Grin's shunt is 1.0mOhm, which they rate for 100A. I'd like something with a lower resistance value but it needs to be the same tiny size and all the other shunts I've seen are physically unacceptable (at 100A battery current, this shunt is causing a 0.1V drop, not the end of the world but can be better so it should be).

Build pics coming shortly.


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

Post by dtx » Jan 05, 2018 2:01 pm

Aren't there any commercialy available adapters for that already? Something like this? https://www.ebay.de/itm/J-L-BB92-BB86-B ... 1825746922

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

Post by tangentdave » Jan 05, 2018 3:30 pm

Those are interesting. I'd prefer if the two adapter cups where secured together, wonder if it really matters though. If we used a hollowtech type crankset, the preload on the BB bearings would hold the cups in place axially. Hmmmm, now we'd need a spindle to match the different BB widths. Some of the cyclone BB's allow the bearings to be positioned at different distances:
Capture.JPG
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Re: Dave's 80:1 RC mid drive kit build log

Post by BonesNis » Jan 05, 2018 4:31 pm

To go from a PF 92 (which your bike has) to a BSA you'll need the adaptor that dtx provided a link to.
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Re: Dave's 80:1 RC mid drive kit build log

Post by tangentdave » Jan 05, 2018 6:22 pm

Right, need 3 things to fit any width BB: Generic PF->BSA
c1.JPG
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Generic BB spindle we can move the bearings wherever:
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Motor unit with adjustable spacers so the mounting plates always sit flush against the face of the BB:
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Again the drive unit fits 73mm BB's natively, spacers will make up any difference. The mounting plate loops around the motor fins tightly so the screws are only holding the plate tight against the spacers, it's quite a solid setup.

I've been searching for an easy way to take care of press fit frames, this combo of adapaters, BB and spacers may do it. Only question is if the PF adapters need to be glued into the frame- I don't think so.

Bravo ES power users.

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

Post by dtx » Jan 05, 2018 7:49 pm

Are those cooling fins for the controller that i spotted there dave?

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

Post by macribs » Jan 05, 2018 7:50 pm

I thought those adapters where press fitted to the frame/bb, but seing the pic you posted I am not so sure anymore.
Anyway, if they will stick with epoxy or some special adhesive it is still an easy fix. The day you need to remove them a heat gun should do the trick just fine to loosen the adhesive.

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

Post by 12-C » Jan 05, 2018 10:43 pm

tangentdave wrote:
Jan 05, 2018 12:35 pm
I think we're going to see some fun bike designs soon. I like the Effigear transmission, they're layout lends itself to ebike use with 3 parallel shafts (we might be able to apply motor power to the middle shaft and run the electrics through the gearbox for the ultimate pedelec). An article in Pinkbike about a similar (same?) frame: https://www.pinkbike.com/news/the-outli ... -bike.html
-dave
Funny you should mention effigear... I just received delivery of their only stand along gear box they have made (to my knowledge), took about 6 months to deliver.
Effigear gear box.jpg
My intention with the gear box was to custom fab a carbon frame that would bolt to the gear box. But seeing as how other things in life are taking over right away, the gearbox with cost about $2500 will likely sit on a shelf till it's obsolete by the time I have a chance to get at it .... A look at the resistence bikes "insolent" frame way it was done really blows my mind.

Looking forward to the new site and the drive!

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

Post by knurf » Jan 06, 2018 4:04 am

Hey I like what I see on the updated landing page, sexy! I want another one.. :D

Are the gears some kind of 7075 alu or did you go back to steel?

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

Post by ThierryGTLTS » Jan 06, 2018 12:56 pm

When using Hollowtech, pay attention to Q-factor which is fairly narrow.

For my -bike prototype, the motor + gearbox + Freewheel is about only 135mm wide to fit the 175 or 176mm Q-factor.

It let me about 4mm between the internal face of the crankarms and the " motor block" on both sides.

Have a Nice W-E.

Thierry

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

Post by ScooterMan101 » Jan 06, 2018 10:36 pm

This is what you really need ...https://praxiscycles.com/conversion-bb/

https://praxiscycles.com/product/shimano-conversion-bb/

The bike shop Mechainc's tell me this is the only real , working , solution. the other stuff just does not work much , the other stuff most often slips inside the BB Shell, with Praxis they fixed that problem with their design.


dtx wrote:
Jan 05, 2018 2:01 pm
Aren't there any commercialy available adapters for that already? Something like this? https://www.ebay.de/itm/J-L-BB92-BB86-B ... 1825746922

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

Post by totolito » Jan 07, 2018 7:52 am

tangentdave wrote:
Jan 05, 2018 12:35 pm
[...] Look at your frame totolito, if you're BB looks like this [...]
-dave

Hello Dave!

Yes it looks like your picture:
Attachments
IMG_20180107_134025.jpg
Hollowtech

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

Post by tangentdave » Jan 07, 2018 1:32 pm

Scooterman, I don't see how the Praxis adapters would work. We need to use the ISIS BB spindle since we need a threaded crank arm to hold the freewheel. It's also convenient to be able to screw on and off the mounting plates via BB cups/flanges. I would prefer a one-piece PF->BSA adapter for each PF standard too. Guess I'll have to try the two-piece myself to be sure it holds.

Totolito, your frame is threaded, no adapters needed.

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

Post by Mugenski » Jan 08, 2018 9:01 pm

I love the that custom heatsink!

I made do with an ohmite SMD resistor. Not a crimp unfortunately but I looked all over and this was the best I found next to grin. I used .5 ohm 6w however there is a .2 ohm 7w that would handle 200A at 0.04 vdrop. I went .5 as I was unsure if it would reduce accuracy on the CA. https://www.digikey.ca/product-detail/e ... ND/5878570
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Re: Dave's 80:1 RC mid drive kit build log

Post by 12-C » Jan 09, 2018 12:07 am

Dave, With water cooling is there any concern with gaseous expansion from heating and blowing past the o-ring seals?

Were you experiencing elevated motor temps that you decided to incorporate a coolant into the new system? What about using a grease based heat sink compound? (Although for a heat transfer compound I'm pretty sure you need an extremely thin film for ideal heat transfer.)

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

Post by tangentdave » Jan 09, 2018 1:07 am

towards.jpg

Ok, 'reference' build. 2011 Intense 951, 83mm BB. All the production parts, production processes, ready to go.

20180108_155042.jpg
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This uses the 20t/32t sprockets previously discussed. These plates were designed for the 16t/24t combo which would have put the idler wheel up higher (will add a few mm's to the mount and another link in the chain to give it a touch more slack). The motor uses the outer sprocket position, inner is now derailleur. The spider mounts on the inside flange of the crank freewheel and we can also replace the motor 32t with the 24t by using a different spider (20t motor -> 24t crank, this would be better for a singlespeed setup).

The Talon ESC is sandwiched under the gold heat sink, 8 screws pulling it against the flat back of the controller. The heatsink (actually two identical heat sinks lined up) comes with a layer of cool phase change heat transfer material to bridge the gaps (Chomerics T766). Imagine the kit/bike a dark color.

Mounting is the same, two plates around the BB with a metal strap over the downtube. These mounts can also be used in a pull configuration (inside the frame triangle) by moving the straps to the bottom side- the other pair of mount positions is just in front of the chain tensioner pivot. Which by the way is spring loaded, bearing mounted and jockey wheeled.
chain tensioner.jpg
The bike is set up with an 11spd derailleur, 3 smallest cogs removed leaving a 42-15t range. The DH frame skews the chainline outboard relative to a normal 11spd frame and I don't want to apply full power to less than a 15t, so the cassette is shifted outboard 3 gears. No problems with any gear under full power, straight chain is dead center of the cassette. The 3220 3turn is 225kV, 52V nominal battery, 20:1 Tangent gearbox gives 375 crank RPM, 32t front chainring to 15t rear is 800 wheel RPM, so 60mph calculated. Plenty. You can hear the wobbly wheels on the bike in the video below, 40mph on the radar sign and the CA read 3kW in top gear and is fast enough for this old sled around my neighborhood. 50mph is well within reach.





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The results of lubricant testing was interesting. More than 30% filled with oil caused unacceptable drag at high speeds, the 16W oil showed the least drag but highest sound level (predictable). The Shockproof oil could work if used in light quantities but is still too thick to drain, so what's the point? Vigogrease RE0 was the winner again, with ~150W ~200W of drag at full speed (all tested at 55V). Our 16W oil came in about 175W drag (30% fill), 80W Bel-Ray gear oil needed almost 300W (30% fill) and the 90/250W shockproof oil needed 400W with a 30% fill. The gearbox is fully sealed now so no need to add grease intermittently. I'll work this gearbox hard and fast to extrapolate the maintenance schedule.

I'm going to be pushing on the big kit, to the neglect of the PAS and 3210 kit. If anybody in the forum wants a 3kW system, sure, no problem, it's the same gearbox but sized for a 3210 and with a 14t motor freewheel. I, however, love the dual-sport bike the 3220 enables. This is where the indestructible reduction gear comes into it's own, 6kW and beyond on the most advanced bikes available, with hardly any penalty. These dual-sport downhill bikes just smash trail. DH bike finesse combined with power wheelies, oh you hooligan!

Based on how the previous generation units performed, I'm going to run my units at 8kW since we have more cooling for engine and ESC. The Talon can transient 150A no prob (the absolute limit is set to 240A) and 14s8p of 25r will support (with sag but far from any damage).

Webstore is open, website is being updated. I'll group orders into batches of 10 to save my sanity. Astro Flight usually needs 3 weeks or so to get an order of motors to me, so lead time should be 4 weeks after the batch is closed. I'll modify this strategy as needed.

I forgot something...remind me


-dave
Last edited by tangentdave on Jan 11, 2018 10:36 pm, edited 3 times in total.
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Re: Dave's 80:1 RC mid drive kit build log

Post by tangentdave » Jan 09, 2018 1:10 am

The water goes into the cooling jacket through that black plastic screw, it's not sealed against gasses. The o-rings are nice and squishy, no leaks. I've got tap water in mine (it's touching only aluminum and o-ring), let's see how long it stays.
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Re: Dave's 80:1 RC mid drive kit build log

Post by dtx » Jan 09, 2018 4:21 am

Wow can hardly wait! AMAZING IT'S HAPPENING!. I don't want to stress you out dave but do you have a rough timeline on looking into pressfit adapters? It seems harder and harder to find bikes with threaded BBS these days!

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