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Weight Weenie Ebike, Nine Months Later

Posted: Mon Apr 11, 2016 2:09 am
by LewTwo
Well it took some time but it is finally up and running ... until I get started changing things at least.
Origonal concept thread: https://endless-sphere.com/forums/viewt ... =3&t=70586

Top speed is around 15 MPH. Much faster on the streets in Houston and it will shake apart (if not the bike then I will). I did get it up to 17 MPH on an unusually long smooth patch of pavement. I did an endurance run with a fully charged battery that managed 10 miles with a voltage drop to 36 volts. I am thinking I could get maybe 12 miles if push came to shove. The battery was custom built by SuPower (10S2P (18650 cells), 36V (42 max), 6.4Ah). Weight is a bit of a disappointment as it tips the scales at 30 pounds as shown. Of course I could leave off some of the comfort items: trailer hitch, pump, kick stand, mirrors, cable lock ... but then it would not be of use to me.

The vintage Miyata CF-7000 Carbon Fiber frame was sanded down to remove all the decals save for the one on the head tube (they had been scratched beyond recognition). Then the aluminum bits were masked off and the frame refinished with High Gloss 2K Glamour Clear Coat. If I was to do it again I would opt for old fashioned lacquer or enamel. The fork was also sanded down to remove the old lacquer finish. Both were polished to a high luster.
Stealth.JPG
As the frame had zero provisions for a rack of any sort I decided to get a Burly Designs Travoy trailer. I adapted my Bushwhacker Omaha Pannier bags to attach to the trailer. This works out well and I can use the trailer with either bicycle.
W-CT7000-0-FR.JPG
W-CT-7000-0-RR.JPG
W-CT-7000-0-RL.JPG
I did not like the way the Bell Handlebar bag conformed to the bike so I put a 1 x 8 inch acrylic bar inside the bag to stiffen it up bit. That bar is drilled and tapped four places 6mmx1. The bolts go through couple of 1/2 x 2 inch acrylic bars on the back side of the fabric bag. There is a 1/2 inch brass grommet in back side for the throttle cable to pass through and a PVC fitting in the bottom for the motor cable to pass through. I replaced the standard connectors on the throttle and control cables with 3.5mm 4 pole phone jacks. The power cables use XT60 connectors and there is an extra one (capped) for charging. .... By the way the cork hand grips are covered with clear heat shrink.
W-CT-7000-HandleBar.JPG
CT-7000-Bag(inside)new.JPG
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The little Bafang SXWU motor's axle only has one side with flats suitable for a torque arm. It happens to be on the same side with the cable and the two of them interfered with each other. I wound up grinding away a bit of the outside diameter of the torque arm accommodate the cable (second picture). The Stainless 'P' clip was fabricated from an oversized clip (beat to fit, match drilled) and polished. A bit of old inner tube protects (I hope) the polished fork from being scratched . I built the wheels from Sun Ringle CR18 eyeleted rims with Sapim Laser Double Butted spokes.
W-CT-7000-Motor-Torque arm2.JPG
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W-CT-7000-motor-cable2.JPG
W-CT-7000-motor-cable2.JPG (216.1 KiB) Viewed 3059 times
The frame's derailleur cable stop was drilled out and tapped 6mmx1 to accommodate the Sturney-Archer cable stop. Despite appearances it is NOT practical for adjustment (too dard little finger space). At some point I may need to add an in-line adjuster to the cable. Note that the SA adjustment screw and cap had to be shortened to get it to fit in the available space (leaving off the lock nut in favor of blue 'lock-tite').
W-CT-7000-Rear Hub-Shifter2.JPG
Sturney-Archer has a lot of shifters available for their 3 speed hubs ... but they are for the right hand side of the handle bars. That side has my thumb throttle. SunRace makes a similar set of shifters for their derailleurs. I took a Sunrace left hand front 3 speed derailleur apart and replaced the rachet with the one from the Sturney-Archer 3 speed hub. To my delight it actually works. It is backwards (silver lever = down shift, black = upshift) but it does work. It needs another coat of black paint to cover up the silver finish.
CT-7000-0-HB Shifter.JPG
CT-7000-0-HB Shifter.JPG (31.5 KiB) Viewed 2902 times
There was inadequate room in the rear dropout to adjust the chain tension and a standard chain could not be made to fit. I did not want to use a heavy chain tensioner so I installed a half link chain. There are very few of those in the 3/32 chain width. This one I chose is a Gusset Bling Slink chain. Best I remember it is 95 half links long. It comes with an 'easy pin' which is NOT all that easy.
W-CT-7000-Chain2.JPG
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The bottom bracket is filled with a FSA K-Force carbon fiber crank and Megaexo ceramic bearings. A Minoura SL-27 kickstand was installed for its light weight and because the Miyata CF frame did not really favor a standard center mount kickstand.
W-CT-7000-BB and Kickstand.JPG
W-CT-7000-BB and Kickstand.JPG (159.09 KiB) Viewed 3059 times
I am not happy with the throttle, handle bars, LED Panel or the handle bar bag.
Then there is that nagging little matter of the extra five pounds.
However the important thing is it RUNS!!!
I can deal with the rest down the line sometime :D :D :D :D

Reference:
Miyata CT7000 1989 http://www.miyatacatalogs.com/2007/12/m ... -1989.html
Bafang SXWU motor https://bmsbattery.com/ebike-kit/602-36 ... e-kit.html
S-KU65 motor controler https://bmsbattery.com/ebike-kit/752-s- ... e-kit.html
SUPOWER Batteries http://www.supowerbattery.com/product/product.aspx
Gusset Bling Slink chain http://www.gussetbikes.com/products-inf ... d=CHGUSL3D
Sturmey-Archer 3 Speed hub http://www.amazon.com/dp/B0042R0YGC
Sun CR18 Rims http://www.amazon.com/dp/B000AO7EYQ
Sapim Laser spokes http://www.amazon.com/dp/B005MJZOTQ
FSA K-Force crank http://www.fullspeedahead.com/products/ ... -bb386evo/
Burley Travoy Bike Trailer https://burley.com/product/travoy/
Bushwhacker Omaha Pannier Bags http://www.amazon.com/dp/B00B4ZKZK0
Minoura SL-27 kickstand http://www.amazon.com/dp/B005UUNUV6
Cork Handlebar grips http://www.amazon.com/dp/B005DUT0G2

Re: Weight Weenie Ebike, Nine Months Later

Posted: Mon Apr 11, 2016 4:04 am
by Ykick
What motor RPM?

Good luck with the controller inside the bag.

Re: Weight Weenie Ebike, Nine Months Later

Posted: Mon Apr 11, 2016 4:15 am
by LewTwo
Ykick wrote:What motor RPM?
Good luck with the controller inside the bag.
As far as I know the 36 Volt SXWU motor is only available as 201 RPM.
After my endurance' run the controller was warm but not so much that I had any problems holding it in my hand. However hotter days are on the way. That is why I am going to look at some other arrangement. One possibility is to put the controller under the bag in the open air.

Re: Weight Weenie Ebike, Nine Months Later

Posted: Tue May 31, 2016 5:27 am
by whereswally606
Lovely clean build, one suggestion I would make is consider a gates belt instead of a chain, there is some weight to lose there for sure.

Re: Weight Weenie Ebike, Nine Months Later

Posted: Tue May 31, 2016 9:48 am
by LewTwo
eTrike wrote:Nice stealth build. 30lbs is light!
Thank thee :)
whereswally606 wrote:Lovely clean build, one suggestion I would make is consider a gates belt instead of a chain, there is some weight to lose there for sure.
The seat stays may look removable but that 'gray' colored stuff around the ends is some sort of adhesive filler. The carbon fiber tubes are actually built up around very thin Aluminum tubes. Then the whole frame was assembled using adhesive cured under heat and pressure. The exact process was never revealed by Miyata. I do not think I want to mess with trying to take 'em apart.

Re: Weight Weenie Ebike, Nine Months Later

Posted: Thu Oct 06, 2016 9:49 am
by LewTwo
LewTwo wrote:
Ykick wrote:What motor RPM?
Good luck with the controller inside the bag.
As far as I know the 36 Volt SXWU motor is only available as 201 RPM.
After my endurance' run the controller was warm but not so much that I had any problems holding it in my hand. However hotter days are on the way. That is why I am going to look at some other arrangement. One possibility is to put the controller under the bag in the open air.
Well it seems I was wrong (again) ...
I was trying to find some additional information for use with a phaserunner controller. Going through my pictures I ran across one I had taken of the motor stamping:
SWXU36V250W205R.JPG
SWXU36V250W205R.JPG (42.58 KiB) Viewed 2132 times
I think that the first Line breaks down to:
Model: SWXU
DC Volts: 36
Watts: 250
RPM: 205
That should work out to 5.694 RPM/Volt or 0.175 Volts/RPM.

The second line could be the serial number, date of manufacture, winding details, gear reduction, other manufacturing data or the interspacial coordinates for a distant planet.
EDIT (thanks to 'hemo') : Second Number is for wheel 26" year manufactured 2015 Feb and hub serial no. The 6 on the end probably designates the factory.

The two places that I know of that sale this model are BMSBattery and GreenBikeKit. The information posted on their web site conflicts with each other and what my motor is stamped. I got this particular motor from BMS Battery.

One other piece of information I have been able to dig up. I found a German forum where someone had taken a SWXU motor apart. I count 16 coils:
8FUN-SWXU-16 Coils.jpg
8FUN-SWXU-16 Coils.jpg (40.08 KiB) Viewed 2132 times
Still looking for the planetary gear reduction ratio.
Reference:
http://www.pedelecforum.de/forum/index. ... iel.39565/
http://www.greenbikekit.com/electric-mo ... motor.html
https://bmsbattery.com/ebike-kit/602-36 ... e-kit.html

Re: Weight Weenie Ebike, Nine Months Later

Posted: Sat Oct 15, 2016 6:52 pm
by LewTwo
In a few weeks I am going to rework this the power system on this bike so I want update to the current "as built".
First of all I got tired of dealing with the 1-1/8 adapter. I got suckered into the fad. I installed a standard 1" long neck steel stem and turned it around backwards for a more comfortable riding position.
Stem (799).JPG
Stem (799).JPG (90.09 KiB) Viewed 1999 times
The bag is now bolted to the stem via an 1" Aluminum clamp. These are VERY handy little clamps (takes 5mm bolts).
Clamp 1Inch No2 Black(400).jpg
Clamp 1Inch No2 Black(400).jpg (20.92 KiB) Viewed 1999 times
The plexiglass stiffening bar inside the bag broke. It was replaced with a piece of 1/2x1/2 aluminum angle. The motor controller is bolted to the bar via one of the through bolts. I also added another grommet to pass the wires through.
Bag_inside (799).JPG
Bag_inside (799).JPG (85.17 KiB) Viewed 1999 times
The seat was replaced with one salvaged from a Schwinn bicycle ... needed something a bit more comfortable.
Rack2.JPG
Rack2.JPG (112.56 KiB) Viewed 1999 times
I do not always want to drag the Travoy around but I did need something to carry things around so I broke down and installed a light weight aluminum rack. As the frame had NO provisions for a rack I used "D" clamps around the seat stays at both top and bottom. Then I mounted the overpriced Travoy hitch to the rack so that I could lower the seat back down where it belongs.
Rack1.JPG
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Rack4.JPG
Rack4.JPG (77.17 KiB) Viewed 1999 times
Rack3.JPG
Rack3.JPG (116.94 KiB) Viewed 1999 times
For version two I intend to:
Relocate battery to underneath rear rack
Provision for GM 36Vx12Ahr rack mount battery on top of rack (when extended range is needed)
Replace controller with Grin Tech Phaserunner (i want to try various setting on the motor) Ultimately I will probably use a EMV3V programmable controller.
Add Cycle Analyst V 2.4 (stem mounted) so I can evaluate the controller changes.

Re: Weight Weenie Ebike, Nine Months Later

Posted: Sat Oct 22, 2016 7:24 pm
by chas58
nice bike. Reminds me of my 29b super commuter! Can't you putbigger tires on there? I like 32mm tires, but 28 is the biggest I can fit on my bike. Still, with 50% more volume than a 23mm tires, and the ability to easily run 80psi, you might find it addresses some of your shanking problems.

Re: Weight Weenie Ebike, Nine Months Later

Posted: Sat Oct 22, 2016 8:12 pm
by chas58
Ykick wrote:What motor RPM?

Good luck with the controller inside the bag.
I blew out two controllers in a bag years ago, before putting the controller out in the fresh air. That has worked fine since then.

Re: Weight Weenie Ebike, Nine Months Later

Posted: Sat Oct 22, 2016 9:14 pm
by LewTwo
chas58 wrote:nice bike. Reminds me of my 29b super commuter! Can't you putbigger tires on there? I like 32mm tires, but 28 is the biggest I can fit on my bike. Still, with 50% more volume than a 23mm tires, and the ability to easily run 80psi, you might find it addresses some of your shanking problems.

The ride quality problems I have are due to the quality (or lack there of) of the pavements that I ride on. I took another close look and I might be able to fit 32mm wide tires in the rear triangle but it would be a very close call. I chose the Red Label Thickslicks because they were the lightest tire that I could find. This was the only size they were available in at the time. I have seen them advertise/listed in 25 and 28 mm but I have never seen them 'in stock'. I have been very pleased with them. The replacement seat has resolved much of my personal ride quality problems but I still get home with half my eggs scrambled :(
chas58 wrote:I blew out two controllers in a bag years ago, before putting the controller out in the fresh air. That has worked fine since then.
I will be mounting the new controller directly to the steering stem and in the open air. However I made it all the way through a hot Houston summer without encountering any serious heat problems. Keep in mind that my longest rides have been less than 7 miles round trip with a stop in the middle to purchase groceries.

I like your tag line "25^3 bike: 25 lbs, 25 mph, 25 mile range". I am going for something like 25^2 bike: 25 mph, 25 mile range on my current build but I think the weight will be closer to 50 pounds.