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

Lethargic, no. I'm just after ways to use fewer electrons. It's cool that Tesla can push 1900A for Ludicrous mode, but maybe there are other ways to get Ludacris to dj your party.
 
Dave,

Some questions:
1) Do you expect any other HW revisions from what you have now?
2) Are you able to ship bare drive units now?
3) Will the length of the 3215 fit between the cranks on a 68mm bottom bracket without modifications? What about a 3220? (Just read through the whole thread, sounds like it will, but didn't see it confirmed)
4) Your images show an HV80 nicely mounted to the motor mounting plates. Will an HV160 fit nicely on there as well?

I already have the following:
Cycle Analyst
Astro 3215
Castle HV160
Magura throttle w/ servo tester
A ton of A123 M1 cells for building a battery

I would be running a 34T Race Face narrow wide to an 11/34 mega range 8 speed cassette in the rear. I know if I move to a 3220 I would probably start wrecking stuff, but ya know, it's all in the name of science.
 
No hardware changes in the near future. I get upset too when I commit to a platform then it gets updated after I bought it. The side plate design with the HV80 mounted are what I want to make as standard. The bolt pattern on the housing allows us to change the plates as we need for special applications (like a Niner WFO). You can buy one drive unit and use the new 83mm and 100mm adapters to swap the same drive between any of your bikes. Press fit BB's are kind of a pain, I'll work on those adapters soon.

I can ship raw barebones units now but all of the black units from this round are spoken for. I'm rushing to get another batch to the anodizing shop Monday, it'll be about 10-14 days before I get that batch back.

The 68mm width, I think what you mean is will a 3215 or 3220 fit between the pedals. The width of the cranks is set by the length of the BB spindle, I'm using the Truvativ Giga Pipe BB's in 128mm and 148mm lengths. The 3210 uses the 128mm width and puts the cranks nicely right up against the frame while the 148mm has about an inch extra on the left and about a quarter inch extra on the right and clears the 3215 and 3220. The 148mm width is available in 68/73, 83 and 100mm BB widths. The width of the drive is 4.5", excluding the freewheel.

I can modify the side plate to hold an HV160 in the same manner as the HV80 now, not a big deal. The HV80 sized plate won't fit the HV160 as is but the two plates would be interchangeable. I would caution against using the servo tester method. Another early user attempted this method and it sounds like he's been able to successfully launch his bike across the street and occasionally he's able to hang on and actually ride. I know the Cycle Analyst is fugly on the handebars, but controlling motor speed is a recipe for disaster. After I make 'em look nice I'm going to publish my wiring diagrams for connecting up the 5k throttles, ESC's with the shunt and wiring in a 6-pin JST connector so you can plug the CA V3 straight to the ESC, this isn't new, others have done this before, it works great.

-dave
 
I've finally finished this idea, the adapters for 83 and 100mm BB's. I wanted to use as few new parts as possible and keep the lines consistent. The 83mm adapter is a simple 10mm spacer that moves the rubber and mount. The 100mm adapter does the same but a step is needed because the left mount plate needs to be held over the allen bolts on the motor (the profiles on the inside). This piece fits tight around the cylindrical housing and is super stable.

1449904778598



This method means each width needs a matching rubber cushion but those are easy and luckily the Giga Pipe BBs are available in all 3 widths. That means this one drive can be swapped between 68, 73, 83 and 100mm frames. I made a few of these adapters and put them in with the shipment to the anodizing shop yesterday so in a week or so we can see these in black.

Astro Flight has shipped the motors and I have the seals so assembly begins.


-dave
 
adriftatsea said:
morati said:
Whats your Heckler weigh without batts? I want to do a Santa Cruz Bronson OR Nomad with this kit.

I'll have to get back to you on that. I rolled it into the office mailroom, wrangled it onto the scale only to find out the scale maxes out at 30lbs.

Bought a new 400lb capable scale and attempted another weigh-in. The bike is at 47lbs w/o batteries. Another 12lbs for my backpack+bikelock+multitool+chain+16ah batteries.

Still no issues with the kit 8)
 
Hi Dave

I'm french racer MTB. I'm riding whith the excellent Pivot Mach6 8)

For the new frame carbon whith BB92 and ISCG05 what do you propose for fixation ??

Your mid drive kit is fantastic !!!

image.jpg
 
DSC_0011 (1).jpg
2015 Intense Tracer 275A, size large.
40.1lbs as pictured...update with upgrades soon!
This thing RULES, so much acceleration!
Thanks Dave!! :D
 
Leebolectric said:

2015 Tracer 275A
40.1lbs as pictured...update with upgrades soon!
This thing RULES, so much acceleration!
Thanks Dave!! :D

Fantastic bike !!! I would like the same motor position on my Pivot Mach6 :oops:

Can i have news pics more near ?
 
DSC_0004.jpg

He has a 1:1 printout on his website...makes it very easy to see fitting requirements.
halfway down the FAQ...
http://www.tangentmotors.com/faq/
 
This early I need to use the Truvativ Giga Pipe ISIS BB's to support threaded trials cranks that hold our freewheel. We can adapt BB30 to BSA with adapters already, but until I have the capacity to make a PF->BSA adapter myself, I don't know we can get this onto a BB92 carbon frame. These adapters are part of the plan but it's still early yet.

If your frame can use a Truvativ Giga Pipe BB, it can fit the Tangent drive.

-dave
 
I love the 951, it's my mini-moto. Sunny in Seattle (finally) and headed up for a ride today actually, let's see if my GoPro setup keeps the camera pointed the right direction this time.

-dave
 
[youtube]m1wYdupfafQ[/youtube]

Just testing the gopro, nothing fancy. Nasty trails tho.

Shopping list:
-cotton balls
-faster trail
-aim the camera at the trail
 
Thanks for the vid Dave! You did pretty well considering that trail was tight and technical and your DH bike with a 62.5 degree headtube angle is meant for bombing downhills at a high rate of speed. Low speed tractability of your kit was clearly demonstrated here......
John
 
I've been watching this for months now and am so impressed with this kit. It's a case of when rather than if ill buy one! Just wanted to throw in my 2 pence. I'm a keen motorcycle enduro bike rider and have been thinking about power to weight ratios. I thought the following power/weight ratio table might be interesting :

Bike Type / Weight /Rider /Total weight /Watts /watts per kg
Yamaha yz125 (33hp) mx / 94 /60 /154 / 25000 /162.34
mountain bike + tangent / 20 /60 / 80 / 3000 /37.50
mountain bike + tangent / 20 /60 / 80 /10000 /125.00

If it were possible to increase the peak output of the tangent kit with a slightly more powerful astro motor it would probably become very much more attractive to off road motorcyclists such as myself.

Just a few a thoughts.
 
I think there are a few who either are well into testing the Tangentdrive with Astro 3220 or will do so any day soon.
For the power to weight ratio you are after maybe you should just jump in and test the drive with Astro 3220 yourself?
 
I've been 'bench' testing the system using the 951 frame. I have access to the input shaft on my test unit, so all I need to do to statically stress the system is lock the rear brake and turn the input with a wrench. This stresses the whole drivetrain- bike, freewheels, motor mounts, chains same as if the motor were turning it. The mounting system is flex-free and solid. There is a tiny bit of rotation as the rubber cushion compresses but I've seen this lessen with time as the rubber begins to remain compressed. The 951 frame begins to flex with 3ft-lbs of input torque (210ft-lbs of crank torque). At about 5ft-lbs the rear wheel is pulled to the right 2mm and the front chainrings have twisted about 5 degrees from perpendicular to the BB (this is 350ft-lbs of crank torque). The 3210 is rated for 500oz-in (2.6ft-lbs; 182ft-lbs crank), the 3220 is rated for 1000in-oz (5.2ft-lbs; 364ft-lbs crank).

Me thinks the best use of the 3220 is along the lines of Joostj- reduce the reduction with a larger motor freewheel to maintain about 200ft-lbs at the crank. The lower ratio means each gear runs longer, so you'd have low gear performance at higher speeds with reduced driveline stress. More torque below 20mph is not needed at this point so the 3220 should be set up to run about twice as fast as the 3210. Easy way to get most of the way there is a 22t motor freewheel and a 30t crank sprocket to get an overall ratio of 54:1, 280ft-lbs crank and 30% higher speed. If there's enough interest I could halve internal ratio to 20:1 so we'd keep the rest of the system interchangeable. Nobody wants to pedal, right?

I doubt any Astro motor could hurt this gearbox. Keep a tiny bit of grease inside and it will handle anything you do it.


-dave
 
Markleeds, for reference, the 951 rides like a 250 four stroke that goes 40mph and weighs 48.5lbs (this morning), high rev torqy engine and all. Imagine everything the 250 does scaled down and without the clutch or tire spin. I can still lift the front till almost 25mph (Fox 40, not a light setup) and this bike is definitely faster than I am on singletrack. Doubletrack and high speed flow trails are ridiculously fast.


-dave
 
tangentdave said:
this bike is definitely faster than I am on singletrack. Doubletrack and high speed flow trails are ridiculously fast.
tangentdave said:
3210 is rated for 500oz-in (2.6ft-lbs; 182ft-lbs crank), the 3220 is rated for 1000in-oz (5.2ft-lbs; 364ft-lbs crank).
If there's enough interest I

I'm glad you're thinking about swingarm deflection and such rather than haphazardly throwing a bigger motor at it. And yeah, once you hit the trails the bike is a monster... but I'm definately interested in some 3220 no-pedal crazyness once sorted. If that means I eventually need a Tangent frame, I'm ok with that.

There's something satisfying about taking off from a stop light, braaaap, lifting a wheel through half of the intersection, and the mechanical enjoyment of powering, noisily (braap!), through the gears. I just wish I could trade some of the Everst climbing low end (I don't even use anything under 4th gear) for a little more 'pedal free' time spent between the gears (and about 7mph more topend).

Then again I sorta feel like I'm complaining that my Ferrari has a poor turning radius for parking lots...
 
+1 signing up with interest for the MegaTangent3220...and cash by the time ya get it figured out. :)
My 951 wants to be the donor...but I'll swap it for another frame if it handles the torque/twist better...stoked to hear how it goes!

If this model is this rad, the next level will be stellar, keep killing it Dave.
 
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