New Giant DH Team/Cromotor build thread

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New Giant DH Team/Cromotor build thread

Post by Obiwan007 » Nov 30 2013 11:58pm

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I have been working on this project for some time now, pretty much as soon as I finished the last one:
http://endless-sphere.com/forums/viewtopic.php?t=46942
I have been riding that bike for the last 8 months or so and have been very happy with its performance especially given that the crystalyte 408 motor is pretty underpowered. But it was my first build and I learned an enormous amount and really wanted a second "trail rated" bike that the SWIMBO and I could go on trail rides with. So here it is! Over this thread I will try to document some of what I have learned in this build from using the Giant DH Team frame with its asymetrical swing arm, replacing magnets in a Cromotor (one of methods last), building my first wheel myself, figuring out how to fit a centered hub motor into an offset drop-out bike, my search, maybe in vain for six pedal speeds and how to fit 18s2p 16ah of battery all into the triangle and make it bullet proof. That's right all of the above and more will hopefully captivate you over the next weeks. Hope it helps someone and maybe someone can help me too along the way (although many already have). Here are few pics of what I have done so far:
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I am going to try to keep up the information in this thread as I go along but this is a start for now. Obiwan
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Re: New Giant DH Team/Cromotor build thread

Post by Scott » Dec 06 2013 8:05pm

You may already know a few of these things.
1. I would recommend Kiwi drop out adaptors. You might have to grind down a corner of the adaptor (15min of work) but other than that they just bolt on to the existing drop out.
http://endless-sphere.com/forums/viewto ... =6&t=33767
2. To fit a cromotor you will need a 150 mm swing arm especially if using kiwi drop outs.
To get one you can buy a 2005 frame off of pink bike (online used bike website) and the drop out inside width should be 150mm. Make sure you ask for the width. If they say yes ask for a picture with a ruler showing the width so you don’t get cheated like I did. Here is one frame for $300. I paid $270 for my second frame but mine did not come with a rear shock and I need a new one.
http://www.pinkbike.com/buysell/1437412/
3. Make sure you order extra c washers for 4 or 5 total to make room for the wiring coming out of the cromotor.
4. Make sure your disk brake does not touch the wires coming out of the motor. It will easily slice right though them.
5. I’m not sure how much but you should order shorter spokes for the left side of the rim. My cromotor is NOT dished and my tire (Maxxis Hookworm) has 1mm of clearance on the right side of the swing arm.
6. I don’t think anything more than a 1 speed free wheel will fit on the back (motor) unless you stretch your swing arm a lot.

We both have similar bikes I’m just using a 24 fet controller and 6s 8000mAh Turnigys instead of Zippys. At first I was going to go with Zippys then I changed my mind. I wish my bike was kept blue like yours I really like the color (some owner before me painted it black). I would be interested to see more pictures of the rack your batteries are sitting on and how close the controller bolts come to the batteries. Also I am curious to why you chose to mount your controller with the wires facing to the front of the bike? Looking forward to see your finished battery box.
Trek Liquid 10 9c 48v 10ah, top speed 28.5 mph. 55.2 mph down a steep hill. - sold
Giant DH Team build http://endless-sphere.com/forums/viewto ... =6&t=51106 top speed 70 mph

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Re: New Giant DH Team/Cromotor build thread

Post by Obiwan007 » Dec 07 2013 12:52am

Scott wrote:You may already know a few of these things.
1. I would recommend Kiwi drop out adaptors. You might have to grind down a corner of the adaptor (15min of work) but other than that they just bolt on to the existing drop out.

Got em, love em

http://endless-sphere.com/forums/viewto ... =6&t=33767
2. To fit a cromotor you will need a 150 mm swing arm especially if using kiwi drop outs.
To get one you can buy a 2005 frame off of pink bike (online used bike website) and the drop out inside width should be 150mm. Make sure you ask for the width. If they say yes ask for a picture with a ruler showing the width so you don’t get cheated like I did. Here is one frame for $300. I paid $270 for my second frame but mine did not come with a rear shock and I need a new one.
http://www.pinkbike.com/buysell/1437412/

I'm going to try my 135mm swing arm first. I know some have gone with the 150mm but others have done it with the normal frame. I'm not ruling it out but with my preliminary measurements and some careful, gentle widening of the rear drop outs I got it out to 145mm with very little effort or stress on the components. It moved right back to the original width when I was done.

3. Make sure you order extra c washers for 4 or 5 total to make room for the wiring coming out of the cromotor.

I actually make my own with nice polished mouths as escapement so for the wires. Careful, careful.

4. Make sure your disk brake does not touch the wires coming out of the motor. It will easily slice right though them.

Got a lesson in this on my first build. Won't soon forget it.

5. I’m not sure how much but you should order shorter spokes for the left side of the rim. My cromotor is NOT dished and my tire (Maxxis Hookworm) has 1mm of clearance on the right side of the swing arm.

Been measuring this detail the last couple of days. Check this earlier thread by me regarding the Giant off-set and the amount of dish necessary to center up the wheel:
http://endless-sphere.com/forums/viewto ... =2&t=55577
I was pulling my hair out until I realized that 1mm of dish removes 2mm of off-set.

6. I don’t think anything more than a 1 speed free wheel will fit on the back (motor) unless you stretch your swing arm a lot.

Got this three speed Como freewheel off amazon. It's 16/19/22 and actually feels pretty good and tight. The quality might not be the greatest but neither was the 11 tooth 7 speed I put on my first build and it has been golden. I threaded it on the motor and it fits within the axel shoulder so.... I'm gonna try it and see what I can do.

We both have similar bikes I’m just using a 24 fet controller and 6s 8000mAh Turnigys instead of Zippys. At first I was going to go with Zippys then I changed my mind. I wish my bike was kept blue like yours I really like the color (some owner before me painted it black). I would be interested to see more pictures of the rack your batteries are sitting on and how close the controller bolts come to the batteries.

The bolts are carriage bolts and the shallow rounded head sit in the bottom of the battery tray. I also counter bored where they sit in the tray so that they are inset into the aluminum a bit (one of the benefits of this thicker material) A 1/4" piece of high density closed-cell foam sits on the bottom of the tray with circles cut out over each bolt head. Then another 1/4" layer of foam sits on top of that. The batteries are wrapped in several layers of the same foam in a thinner gauge. It fits very snugly into the bottom tray. The tray itself is 5" wide architectural aluminum channel (6063 with sharp corners inside and out) with 2" legs and 3/16" wall thickness. It's softer than some of the other extrusions since it is not generally meant to be structural but with that wall thickness it's plenty stout for this application. I shortened the legs to 1". The torsion rods between the tray and the controller bracket are just some thick walled aluminum tubing. The torsion bolts (carriage bolts with the square part passing through the bottom of the battery try) go all the way through the controller bracket and secured with whizz nuts.

Also I am curious to why you chose to mount your controller with the wires facing to the front of the bike?

I make a snap-on cover that goes over the whole controller and the wiring bundle. See:
http://endless-sphere.com/forums/viewto ... &start=100
I just think it looks better this way with the cover on it.

Looking forward to see your finished battery box.
Got some work done on it over the last couple days. Embedding the wiring harnesses in the foam etc. took pictures and will post them soon.

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Re: New Giant DH Team/Cromotor build thread

Post by Scott » Dec 07 2013 2:09am

I ended up needing 3 c washers on the wire side to give my wires enough room to come out of the motor and also for the disk brake bolts to clear the kiwi drop outs. The C washers I used are 1/8” thick each for a total of 3/8” thick. On the right side (chain side) I have the free wheel washer that came with my motor. I would guess it is a little less than 1/8” thick. Also with the Giant DH Team swing arm only one side flexes when it is stretched out. I believe it is the left side? What I am trying to say here is more spacers are needed on the left (brake side) of the motor than the right.

You probably already know this but the kiwi drop out adaptors add 5mm or so to each side so now your dropout width might be around 125mm or so instead of 135mm. Even with my 150mm swing arm I still have to stretch it 5-7mm when I put the motor in.

Now that I think about it I remember that Binlagin did get his cromotor in the 135mm swing arm.
Here is a link if you have not seen it yet.
http://endless-sphere.com/forums/viewto ... =6&t=36090
Trek Liquid 10 9c 48v 10ah, top speed 28.5 mph. 55.2 mph down a steep hill. - sold
Giant DH Team build http://endless-sphere.com/forums/viewto ... =6&t=51106 top speed 70 mph

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Re: New Giant DH Team/Cromotor build thread

Post by Obiwan007 » Dec 07 2013 3:25am

Thanks for the comments Scott, your links have been giving me some good food for thought. My current drop-out width is 132mm with the Kiwi adapters installed. I did a lot of clean-up on them and took down some high spots to maximize the clearance. As you say, I suspect when spreading the arms that one side is moving more than the other. The drive side I think. I plan to put about 14mm of dish in the wheel build. By my calculations that should bring me to within 2-3mm of center line. This makes the brake side spokes pretty vertical but GCinDC has been running his that way for some time now with no problems. I'm initially going to use 2.75" Weirwolf tires so there should be plenty of room. If those appear to have extra clearance I will try out some 3" Nokian Gazalodi tires that I have been hoarding. If I am then plagued by flats then I may switch to the MC tires/wheels I have been running on the "Electric Jeepster". Obiwan

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Re: New Giant DH Team/Cromotor build thread

Post by Obiwan007 » Dec 07 2013 3:27am

Hey Scott, do you know, are the 150mm swing arms exclusively off the frames with the down swept top tube or did they make some with the straight top tube that had the wider drop-outs too? Obiwan

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Re: New Giant DH Team/Cromotor build thread

Post by Scott » Dec 07 2013 2:01pm

Obiwan007 wrote:Hey Scott, do you know, are the 150mm swing arms exclusively off the frames with the down swept top tube
Yes, the 150mm swing arms are exclusively off the frames with the down swept top tube and they were the last line of the Giant DH Teams/Comps. That model was made in 2005. Moonshine said he contacted Giant and ordered a new 2005 swing arm from them for $220.

Also I would advise not using the pinch bolt on the brake/wire side of the motor because it pushes the wires out into the disk brake. I'm sure you will probably find a way around that. Although the axle will probably break before the torque arms do.

Do you have any links of what foam you bought and where from? I need to do something similar with my box.
Trek Liquid 10 9c 48v 10ah, top speed 28.5 mph. 55.2 mph down a steep hill. - sold
Giant DH Team build http://endless-sphere.com/forums/viewto ... =6&t=51106 top speed 70 mph

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Re: New Giant DH Team/Cromotor build thread

Post by Obiwan007 » Dec 07 2013 3:19pm

Here are a few more pictures.
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Cut out some channels in the foam to serve as secure conduit of the wiring harness. The first picture shows a hole through the foam that allows the wires to pass from the disc side to the drive side so they all meet up.
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Same arrangement for the front two batteries with a pass through hole.
Everything will run along the top of the foam and exit at the back to a six gang anderson that will mate to the series harness going to the controller. I had to play around a lot to get the batteries in this arrangement here is the way I puzzled the bottom brick of four together:
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I looked around a lot for the closed cell foam and ended up getting it in 2" thickness of the higher density from a place on the net called Allegro Medical then bonded three layers of it together with 77 spray adhesive and cut it to shape on my band saw.
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After cutting the channels, I trimmed the off cuts and put them back in the holes to give a nice soft conduit for the wires. The side covers will hold everything snugly in place.

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Re: New Giant DH Team/Cromotor build thread

Post by Obiwan007 » Dec 26 2013 6:38pm

Been a bit since a posted on my build but I have been working steadily during that time if not prodigiously. Still waiting for replacement magnets for the Cromotor but I think it will work out in the next couple of weeks. Kind of good that I have to wait though since I have still not committed to either the 135mm swing-arm or the 150mm. The one thing that the 135 has going for it is that I have one. I have been working hard to find a 150mm but have yet to lay hands on one. Thought I had a deal off of pinkbike but the seller flaked out. When I get the motor repaired I will have to fish or cut bait though because I won't be able to hold off on ordering spokes any longer. If I don't have a 150mm swing arm by then I am going to proceed with a rear wheel that is dished by 14mm. In other news I got my side panels for the battery box done. A family member has a sheet metal shop in a town not that far from me and offered to work with me on building some nice aluminum panels. When I got the chance I traveled there and he worked out the drawings and then shipped them out to the lazer cutter and the CNC press brake. Here he is drawing them up:
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There are three panels, a left, right and rear. The laser cut them all out in 20 seconds! Here:
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Then over to the press brake which already had the bends specified for the job. It has a sensor in it that measures the bend as it is being done, stops just short, let's up and measures the spring back and then finishes the bend to exact tolerances...AWSOME.
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Bending the side panels.
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A finished side panel.

After that he pressed in some PEM inserts (like nut-zerts but better) where the panels will overlap at the top. Then he spot welded a stiffening rib along the rear edge that will also serve as the mount for the rear panel. I plan to have the rear panel mount with strong magnets so that it is easily removable. The sizing of the side panels creates a compartment at the rear that will provide plenty of room for wiring and this is where I will have access to my charging plug and balance leads. Here is what it looks like on the bike:
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I am considering getting these panels anodized black for durability and stealth. Any thoughts?
I also made up a mount/dashboard for the CA and the "key". I found this item on HK international
http://www.hobbyking.com/hobbyking/stor ... Plug_.html
And thought I could use it as a kill switch by running the the ignition wire through it and then wiring the legs of the deans plug together. I think it is going to work great and it looks pretty custom too. I'll get some pictures of it later. I think I'm going to lace the rear wheel myself. The front one turned out great so I think I will give it a try. Ready to start getting the wiring all lined out now. Should be pretty straight forward. Lots yet to do but....getting there.

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Re: New Giant DH Team/Cromotor build thread

Post by Obiwan007 » Dec 26 2013 6:48pm

Forgot to mention, if you want a set of these side panels the sheet metal shop has them all set up in the computer and can run them. You would need to use the same size bottom tray as me for it to work but this 5" wide architectural aluminum channel is readily available (heck I have about three feet of it left over). The panels are simply held on by two small bolts on each side at the bottom and then the panels are pressed together to compress the foam and three screws through the PEM inserts on the top. Pretty easy system with no complicated mountings and it is uber-secure. I don't know what they would charge but the set up is already done and with the laser and press brake already programmed there is less than 30 minutes of labor.

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Re: New Giant DH Team/Cromotor build thread

Post by Obiwan007 » Jan 04 2014 3:27am

So I just got my perfect side panels back from the anodizing shop and they look great but are all jacked up. Apparently they got them too hot some how and warped them...a lot! They also burned out the PEM inserts because they were steel and they did not know to mask them (like everybody uses aluminum threaded inserts) Here is a pic of the rear panel on a flat surface:
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This is the side panel, that whole left side should be flat.
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They won't even fit on the bike any more. Arrrrgh!! So I spoke with my relative and he thinks he can straighten them out without jacking up the finish. I sure hope so. I'm gonna hash it out with the plating shop tomorrow. Obiwan

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Re: New Giant DH Team/Cromotor build thread

Post by Arlo1 » Jan 13 2014 11:46am

I can help but I need to read this when I get home.
My Leaf motor controller build. http://endless-sphere.com/forums/viewto ... 27#p963227
My YSR build http://www.youtube.com/watch?v=BRo8r5g4NBg
RC and most types of Lithium batteries you MUST know your individual cell voltages charging and discharging.
Don't keep them were you cant afford smoke or fire!
Never above 4.2v never below 2.7v EVER!!!
Support me on Patreon. https://www.patreon.com/user/posts?u=6842045
http://www.undergroundelectrics.ca/

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Re: New Giant DH Team/Cromotor build thread

Post by Obiwan007 » Jan 18 2014 6:54pm

Well as it turned out I had to have the side panels re-made. Straightening them made them look like hell. So, waiting for those and then I have to decide if I want to take a chance on anodizing again. Used the time to get my motor all repaired. Finally got my hands on replacement magnets for the two broken ones and gluing them in place was pretty straight forward. I used the scotch weld DP 460 epoxy and it worked a treat. Baked it for an hour at 160 degrees afterward and it hardened right up. It has a much longer open time than other epoxies I have used and (bonus) no noxious odors. I also took the opportunity, with the covers off, to do a little modification to the drive side. Problem was, I wanted to use this three speed free wheel in found but it would not seat down properly onto the bearing surface due to the bolt heads for the center bearing mounts seen here:
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This also caused the freewheel to sit proud of the threads which would necessitate using washers to clear the drop-outs:
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Given that I still have not gotten my hands on a 150mm drop-out, I really don't want to add any extra width if I can help it. So I took a three pronged approach to lowering the bolt head profile. First I switched out the bolts for some stainless ones that were slightly lower profile. Second I ground down the heads just a little. Third, it turns out I just happened to have a guided counter bore that was the right size and only needed the guide ground down slightly to work perfectly:
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Made a nice counter bore for the bolts to sit in:
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This allows the bolt heads to sit just below the level of the bearing surface and also allows the threaded surface to sit proud of the freewheel.
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Now I have to figure out how to get the disk to work without using spacer washers too. Any ideas?

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Re: New Giant DH Team/Cromotor build thread

Post by Scott » Jan 18 2014 7:26pm

I like how you solved the freewheel clearance problem.
Obiwan007 wrote:Now I have to figure out how to get the disk to work without using spacer washers too. Any ideas?
There this:
http://endless-sphere.com/forums/viewto ... 25#p535553
Although the last time I checked that brake was no longer in production.

If you don't use spacers on the disk side the bolts holding the disk on will hit the torque arm. Also the phase wires will probably not have enough room because the axle gets larger where the disk is at and they don't fit to well through the torque arm.

Where did you find those bolts at that you used for your freewheel? I need some for my disk brake, I checked at Lowes but they did not have any with the heads rounded off.
Trek Liquid 10 9c 48v 10ah, top speed 28.5 mph. 55.2 mph down a steep hill. - sold
Giant DH Team build http://endless-sphere.com/forums/viewto ... =6&t=51106 top speed 70 mph

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Re: New Giant DH Team/Cromotor build thread

Post by Obiwan007 » Feb 02 2014 1:34pm

Hey Scott. I am pretty pleased at the way this turned out for the drive side. My alternate plan was to use one of these Dos Eno freewheels from white industries:
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I'm sure this 3-speed freewheel is pretty low quality so I'm going to wait and see how well it lives. I got these bolts from Ace Hardware. The one near me has the best fastener selection in my area. Unfortunately, you do need to take the side cover off to do this mod since the bolts are held on the inside by nylock nuts. If you are serious about doing this modification, I would be happy to send you this guided counter-bore to use. It sure made the job easier. I have some ideas about lowering the profile on the disk side too. Similar to your link above but with a twist that will allow it to work with my calipers and to also eliminate the disk bolt head problem. I talked about it here:
http://endless-sphere.com/forums/viewto ... 62#p849762
And will document it here if I ultimately decide to do it this way.

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Re: New Giant DH Team/Cromotor build thread

Post by litespeed » Feb 03 2014 7:17am

Nice!

Tom
I'm married so you know I'm no stranger to pain!

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Re: New Giant DH Team/Cromotor build thread

Post by Scott » Feb 03 2014 5:15pm

I had no idea a 3 speed or even 2 speed freewheel would fit on the drive side without needing spacers. Even though I have a 150mm swing arm I do not want to stretch my frame any more. I really appreciate your offer, but I purchased a single speed 18 tooth freewheel months ago. I just have not taken my bike back apart to put it on. Although I should have put it on, because I have been stranded 3 times with no working pedals.
I am thinking about having the pinch bolt on the outside of the dropout. My idea below is not the ideal way to pinch the drop outs but it may be the only way with giving the wires more room in between the disk and the axle.

How it normally is done:
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My idea of how it could be done:
DSCF0401 my idea low res.jpg
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Trek Liquid 10 9c 48v 10ah, top speed 28.5 mph. 55.2 mph down a steep hill. - sold
Giant DH Team build http://endless-sphere.com/forums/viewto ... =6&t=51106 top speed 70 mph

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Re: New Giant DH Team/Cromotor build thread

Post by Obiwan007 » Feb 03 2014 6:59pm

That's an interesting idea Scott. Are those the actual components you plan to use? What are they made of? So if I am seeing this right you are making something that would act like a "C" clamp..right? Seems like it should work if you can get enough pressure on it. I just don't think I'm going to need it on mine. Even with the disk all the way out at the standard mount position on the disk adapter, the wires only have to lift slightly to get over the pinch bolt and still travel through the remainder of the drop-out slot. A couple of smallish zip ties inboard of the drop-outs keep the wires down and away from the whirling sharp disk edges. On mine I rounded off the sharp parts and then sanded and polished them as a back up in case the zip ties failed. That's how I have it on my other bike and it has been golden. As for the three speed freewheel, I got it on ebay and it came from China. I gather that it is a stock part for some of those three wheeled sort of granny trikes that you see around. There were two types with different size rings but this one had the smallest ring of the two. My challenge now will be to get a deraileur and shifter that will work. I'm thinking a 5 speed and screw in the limit screws to hold it to just three speeds. I originally wanted to use a three speed shifter for a front deraileur but apparently the cable travel per click is different for fronts. There are some devices for changing the amount of travel like this one:
http://jtekengineering.com/shiftmate.php

That may get a three speed shifter to work but I will have to work it out when I get to that part. If I ultimately have to go to the 2 speed Dos Eno, the shifting part might be even harder. I have been looking at the method for mounting the disk backward, sandwiched between the disk adapter and the shimmed side cover. It looks like it will work just fine. If I don't find a 150mm swing arm by next week end I'm going to take the plunge. Accountant say he has replacement disk adapters if I run into a problem and need to back out. It still looks like I may be able to shorten the axel shoulder by about 3-4mm too. I'll get everything else done though before I take that particular plunge. I should be able to chuck the whole motor up into the lathe though so it should be pretty easy if I do decide to do it. I also evaluated lacing the motor up with the spokes all on the same side of the flange. It looks like that will yield 6mm closer to center line all by itself. So if I add that to the 3mm of axel shortening I have 9mm closer to center. I initially figured that I needed to move it over 14mm to get the tire centered up, so that should mean I only need 5mm of dish in the wheel. The benefit of doing that, as I see it is that the spokes on the disk side won't be at quite as steep an angle.

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Re: New Giant DH Team/Cromotor build thread

Post by Scott » Feb 03 2014 7:32pm

Obiwan007 wrote:Are those the actual components you plan to use? What are they made of? So if I am seeing this right you are making something that would act like a "C" clamp..right? Seems like it should work if you can get enough pressure on it.
No, this was a quick prototype made out of Lego. Yes it would similar to a C clamp. My main problem is I need to get rounded off bolts to mount my disk. The bolts holding my disk on are so large they come pretty close to hitting the wires.
On my first electric bike I bought 6 speed shifter to work with a 8 speed derailleur with my 6 speed freewheel. I just set the limits on the derailleur and it worked great. Except for my derailleur was bent and scraped my hubmotor in first gear so I just set the limit to second gear as the lowest gear, so the sifter could not be shifted to first gear.
Trek Liquid 10 9c 48v 10ah, top speed 28.5 mph. 55.2 mph down a steep hill. - sold
Giant DH Team build http://endless-sphere.com/forums/viewto ... =6&t=51106 top speed 70 mph

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Scott   100 W

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Re: New Giant DH Team/Cromotor build thread

Post by Scott » Feb 04 2014 1:03am

I just looked on pink bike and saw "Giant DH Team Swing arm 150mm" and I was like perfect!! Until I realized it was your post.

Here is a 2005 frame for $200:
http://www.pinkbike.com/buysell/1480412/
Or a whole bike for $650:
http://www.pinkbike.com/buysell/1455685/
make sure you have the take a picture with a ruler measuring the swing arm so you know its the right one. It should be 155mm metal to metal or 150mm metal to derailleur hanger.

I would say the frame is a good deal because you get a shock with it. Mine was almost $300 after the guy kept the shock. Also if you buy just the frame take the front triangle too. Tell them to pack it or their bike shop to pack it with the swing arm around the front triangle then, shipping is not very expensive at all.

edit: Just realized they say local pick up only. Still ask them if they will ship it. I saw some bikes on there still from a year a go when I was looking for one. I doubt they will sell at local pickup only.
Trek Liquid 10 9c 48v 10ah, top speed 28.5 mph. 55.2 mph down a steep hill. - sold
Giant DH Team build http://endless-sphere.com/forums/viewto ... =6&t=51106 top speed 70 mph

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Obiwan007   1 kW

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Re: New Giant DH Team/Cromotor build thread

Post by Obiwan007 » Feb 04 2014 1:51am

Thanks for checking on swing arms Scott. Unfortunately I have already made inquiries for the bikes you recommended some time ago. The first is a scam. In dealing with that particular drug addicted thief I went so far as to have a representative in the same town attempt to contact him for the "local pick-up". When he discovered that the buyer would not pay in advance he bailed. The second one you you have there is a seller, like many I have tried to contact, who simply won't reply back. I think it is likely that they sold their bikes and simply failed to remove it from pink bike. I have made inquiries for every bike that has come available on pinkbike here in North America, Europe, Australia, South America and Asia. In addition I do a nationwide search of Craigslist every day. I don't care if it says local pick-up or not I still try to contact them and talk them into it. If they still don't want to ship then I start looking for someone I can get to do a local pick-up for me. I really am trying to find one. It has been particularly frustrating due to the fact that on three separate occasions now I have had what appeared to be a deal worked out only to have the seller go dark and stop responding. It's really kooky. I'm starting to think it might be some weird internet game that kids are playing to see how long they can string someone along. Anyway, like I said, I'm giving it one more week of searching and then I am jumping into the 135mm custom job. If all else fails, I can probably swap out the Cromotor for a 4080. But that will be my very last option. It feels like a challenge now that I must master :x

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Re: New Giant DH Team/Cromotor build thread

Post by Obiwan007 » Feb 04 2014 1:56am

Scott, definitely get the regular bolts for your disk they are nicely rounded with heads that are smaller than the disk material so they don't stick out. They are usually torx drive and any LBS should carry them for real cheap. You probably won't need to do the whole c-clamp thing if you do. Obiwan

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Re: New Giant DH Team/Cromotor build thread

Post by Obiwan007 » Feb 05 2014 8:14pm

So I got to work on this a bit today. I figured that no matter which way I go with the swing arm I still need the caliper to line up right and there is nothing wrong with putting the disk bolts on the inside. So I moved forward with making the shim that will gap the disk out from the side cover just enough and also allow me to bury the disk bolt heads when it is screwed onto the back side of the disk adapter. Here is how I proceeded
Attached the disk adapter to the disk and drilled out the clearance holes for the disk adapter bolts:
image.jpg
Drilling the disks turned out to be easier than I thought. The holes drilled nice and clean with a standard #9 drill bit.
image.jpg
Then I made one of these shims.
image.jpg
Had the material laying around of about the right thickness. I also had a disc spacer shim (from grin) that I used as a drill guide to get all the holes in just the right spots. Then attached it to the disc adapter and drilled the those mounting holes. Now to open up the disk holes to provide clearance to bury the disk bolt heads. Simply used a 23/32" bit and went slow to get just the right depth. And finally sanded to scribed compass marks for the outer and inner circumferences. The center hole was drilled and then hogged out with a copping saw then filed and drum sanded to final size. This is how it works:
image.jpg
First the disk adapter (which will later be milled down to reduce it thickness when I know just how much) gets bolted to the disk, on the back side. Then the shim sits down over the disk bolt heads:
image.jpg
image.jpg
You can see the disk bolt heads peaking through the holes. Then the whole rig gets bolted to the side cover:
image.jpg
image.jpg
Here it is, disk adapter is the outside surface now with no protruding bolt heads to contact the drop outs. Once I mill down the thickness of the disk adapter it will be below the level of the axel shoulder:
image.jpg
Here is the caliper clearance to the side cover now:
image.jpg
Just got a line on a shop that is willing to custom modify my swing arm. They are evaluating the job now and will be giving me a price. If it is reasonable, and good, this will represent a future option for Giant DH builders. They claim to do this type of work all the time and can handle exotic alloys and re-heat treating. I talked to him about all of my geometry concerns and he seemed to have it all handled. So here is hoping! If it's anything less than $250.00 it will be a bargain. The guy was recommended to me by a family friend who is a long time rider and a LBS owner so, good references. I will see this modification option through but if it does not work out I'm going to move forward with motor modifications to get this thing to work on my current swing-arm. Obiwan

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Re: New Giant DH Team/Cromotor build thread

Post by trevc2 » Feb 06 2014 1:32am

I don't have cranks or bottom bracket fitted to my DH Comp yet (but thankfully found a 150mm swing-arm in Perth). Do you happen to know what the maximum width of a battery box could be that wouldn't be hitting the crank arms?

Cheers

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Re: New Giant DH Team/Cromotor build thread

Post by Obiwan007 » Feb 06 2014 9:04am

I'm on duty at the fire house today and tomorrow but I will check it on Saturday. Obiwan

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