Ch00paKabrA Giant DH Comp - Finally Done!

Ch00paKabrA

10 kW
Joined
Mar 15, 2013
Messages
670
Location
the Jersey Shore, NJ
Edit: Here is the DH Comp as it currently stands:

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The Original post was stupid so I edited the stupid parts out :D

Form the original post:

Here is the basis for my build:

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2002 Giant DH Comp (135mm drop-outs) Marzocchi Drop-off triple forks and pro-wheel 19 x 2.15 rear and 1.65 front blue rims.

I picked up a pair of Drop-off triple forks that supposedly needed work. I tore both of them down thinking that I might be able to make one good one, but I couldn't find a thing wrong with either one. Neither is leaking oil and both hold air and the internals look like new. So now I have 2; one for a QR axle and the other for a 20mm axle. The 20mm one is going on this bike.

I will be using IRC GP1 2.75 x 19 trials tires:

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I will be using a MAC 6T rear motor. Right now I have on the back of my HardRock (which is also sporting the other Marz Drop-off). I slapped this together just to get a feel for the motor that I got in trade with a member here for a brushed mid-drive kit that I wasn't too fond of. At the moment I only had a spare 36v 250w controller and I must admit that I like it. It pulls hard even with the fast wind and only 250w. It will go almost 25 mph on 36 volts so I think it will be fine with around 1000w and 72 volts. (if this out of line for this motor, please tell me now before I progress too far.

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So, This brings me to the first known unknown (to quote Rumsfeld) - The Battery.

I would appreciate some input from those who are more knowledgeable than me.

First off. I just finished remodeling my house and I bought it less than a year ago. Therefore, Lipo is out of the question. I will not risk burning it down. 18650s seem like the way to go and after reading SpinningMagnets' article on high drain 18650s, I believe that I will be happy with the results. For my specialized build, I used Samsung 29E batteries and build two 4 10s 3p packs and two 10s 2p packs that I am running parallel at 36v 29ah. This is fine at 250w and maybe even 500 but I am unsure whether these batteries will be OK for 1000w.

Here is a tracing of the triangle area with two configurations for the battery cells:

Option 1:

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Option 2:

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I used pennies to lay out the cell locations since they are 19mm in diameter so I will get a good idea of how many I can fit in.

I intend to run this motor at 72 volts and either 750 or 1000 watts. Therefore, I am looking at using 140 cells 20s 7p.

I found a new battery that came out of Japan specifically for the e-cig crowd. It is a 3.7v 2500 mah 35a drain 18650 at around $4.50 (probably $5.00 after shipping). I think it is comparable to the Samsung INR 25r but is at least a dollar cheaper.

What do you think regarding my battery ponderings?

The goal for the bike is to be able to cruise at around 30 mph. It will be mostly street riding but pot holes get to be pretty messy here in the Northeast.

That's it so far. In this thread, I will also update my progress on the HardRock as now that I have it functional, I intend to make it pretty.
 
leonardo said:
Why did you choose li-ion batteries? Was LifePo4 not an option?

It was simple math for me. There is limited space available in the triangle and the LifePo4 are 3.2 volts where the lipo are 3.7 volts. Also the Samsung 22Ps are only $3.50 including shipping and the 29Es are only $0.50 more. I decided to go with the 22Ps since the c-rate is a little higher. I ordered 200, so I will have 140 in the frame and 60 in an extra large under seat bag. This will give me 20s (72v) 10p (21.5ah). At 5c per cell, I think they will be able to handle one of Lyen's mini-monster controllers. Unfortunately I can only wire the BMS to the cells inside the triangle. Still waiting for the batteries though.

Edit: too many spelling errors :oops:
 
I like your project.
Slowly gathering all the components, choosing the best you can afford, aren't you?
For my own project I did choose for a lifepo4 though. 72v 15Ah coupled to a Lyen's controller and a Crystalyte Hub moter.
I am very curious about your progress, please keep the nice pictures coming.
 
leonardo said:
I like your project.
Slowly gathering all the components, choosing the best you can afford, aren't you?
For my own project I did choose for a lifepo4 though. 72v 15Ah coupled to a Lyen's controller and a Crystalyte Hub moter.
I am very curious about your progress, please keep the nice pictures coming.

Yup, I'mm taking my time with these. This thread will cover 2 separate builds. My Specialized Hardrock with a mini hub that is running a bafang 36v 250w motor on 72v 350w and the giant DH Comp that is running the MAC 6T. It will be 72v and I am corresponding with Lyen at the moment to determine the best controller for it. He has suggested his mini-monster controller.

I just finished ordering the parts for the Hardrock. I ordered 2 Alex DX32 24" rims since these are the widest I can find, and a pair of 180mm rotors. Also ordered is a new riser handlebar and a new set of custom graphics in Highly reflective white material. It is the stuff that they put on bike packs that lights up when a car's headlights shine on it. I also managed to find some alloy bits that those plastic "c" clips clip onto to hold the brake cable nice and tidy.

I need to have a bike to ride so as soon as I figure out how to make the drop-outs for the DH Comp, I will tentatively put it together so I will have something to ride.

After that, there is a custom choppers garage about a few blocks from my house and they will be doing the HardRock in Pearl black and applying the graphics for me. At first he didn't want to do it but since it has a motor, it is technically a motorcycle and it is being customized so in a sense, it fit in with his mission statement - lol.

I think in about a week or so, it should go in for blasting and paint. I don't know how long it will take. After the HardRock is done, I will really start taking the DH Comp seriously.

The last thing I have to order is a new set of graphics for the forks. So here is a question if anyone wants to chime in:

Should I be a liar and put 888 graphics on my Drop-off forks or should I just get a set of Drop-off graphics and let everyone know I am a cheapskate?
 
Parts are starting to arrive. these are for the HardRock though, not the DH Comp but the spokes will allow me to put the Bafang back on the HardRock so I can put the MAC on The DH Comp.

I got tired of only having 1 gear so I broke down and bought a shifter for the rear:

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I always buy cheap spokes initially. I am terrible at sizing them. It should be easy with all of the spoke calculators out there but I always manage to screw them up so these are cheap BMX spokes @ $15.00 for 36 including nipples. If the size correct, then I will get better spokes.

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Before I "knew" better, just ran a set of these with this same motor for 2000 miles and never had a problem so even though I will get better spokes, I am not in a rush to do so.

I searched high and low for a wide 24" rim and finally went to my LBS who came up empty as well. These were the widest that I could find @ 1.5 inches wide. Alex DX32. They appear to be of decent quality and the 24 x 3.00 Fatti-O tires looked comical on regular rims.

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Here is a comparison shot of a regular rim off of a Sears Schwinn bike and the DX32:

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Time to start lacing up the new wheel I guess.
 
I laced up the wheel last night and, of course, the spokes were too long by a few mm. I believe that the ERD must be wrong because I used 3 different spoke calculators and all came within 0.5 mm. This is why I buy cheap spokes first.

On a side note, I have laced quite a few rims in the past but all were the single walled rims that come on cheaper bikes. They usually start to get wobbly once you start to get the spokes tight. This DX32 remain perfectly round and perfectly true throughout the whole process. I had to do no individual adjustment. I am sure one the spokes start to stretch I will have to make some corrections but it was a pleasant surprise.
 
A few more components came in today. One for the DH Comp and one for the HardRock.

Most of the bolt on parts are going to be carbon fiber to save some weight (not that it will make a huge difference).

The first to arrive is the Handlebar:

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the other piece that came in is a front hub for the HardRock. Even though it is not a very fast bike, I never really trusted QR hubs so I tended to go for the bolt on axle hubs. I thought I would have to use a ball bearing hub but I managed to find this nifty hub with sealed bearings and a bolt on axle. I have never heard of the company before - Quanda (I think) but after googling them, they are a fairly inexpensive hub but not the cheapest. so we shall see if it is fit for duty.

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I took the bike out for a spin today and the tire was hitting the frame so I had to do some adjusting the wheel dish. I got it so that it is perfect so hopefully it will stay. There is only about 2 mm on either side between the tire and the frame.

Working on the drop-outs tonight and until they are done, I will focus on them. I considered Kiwi's drop-outs (as well as taking over the production of them) but in the end I think I will make adapters and use Doc's torque arms and that high strength epoxy he used.

The other issue I had is that the guy at the custom chopper shop said he just doesn't have time to paint my frame. I guess that is good for him but bad for me since I suck at paint. I am also rethinking my black with blue metallic flake color choice and may go with a brilliant green or something else entirely. I'll have to see.

I am still waiting for the 72v 350w controller to arrive. It is one of the few remaining component for the HardRock that I am waiting for.

That's it for now.


That's about it for now.
 
I started the Drop-outs. This is very time consuming as I don't have a Machine shop at my disposal. I have a hack saw, a few files and a drill so we will see how they turn out. Here is the preliminary right side. I just finished the top and it took me almost 2 hours:

View attachment 1

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It's rough because it is my busy season so I don't have a lot of spare time. Both bikes are coming along though.
 
agniusm said:
Save yourself some time and get a cheap grinder.

I've got grinders; a bench-top stone grinder and a handheld which I will use to brighten up the finished product. I am using a saw and files to get it right. I am not really in a rush but I do need the drop-outs so that I can use the DH Comp while I do the pretty work on the HardRock.

The 72 volt 350w controller came in for the HardRock yesterday so I thought I had everything I needed but I then noticed a lot of play in the headset so I ordered a new one. The old one is the old school ball-bearing-in-cage type so I am swithing over to a sealed bearing unit.

Hopefully it will be here soon so I can finish at least one bike.
 
izeman said:
nice project. how are you gonna install the batteries in the triangle? in a bag? or are you gonna cut the frame and weld (or let someone weld) a box?
also i don't know NJ. if it's flat like FL you're fine with the 6T, but i would prefer the 10T if you got any mountains.

The batteries are going to be installed in a custom PVC or fiberglass case in the triangle. I can fit at least 140 18650s so there should be plenty of juice. I live right at the beach so it is flat here. There are sometimes issues with the wind though. It can make you feel like you are going up-hill.

I truly understand why people just buy Kiwi's drop-outs. They are a real pain in the ass to make. I learned the hard way that you drill your holes first to mate with the holes on rear triangle. I had a perfect fit in the wavy deraileur hanger section then screwed it up drilling the holes.

I decided that since I will never be using the bike for its intended purpose, I may as well go ahead and cut up the drop outs instead of try to fit steel to them.

I needed to move the wheel back a bit and I found these for a good price so I will be modifying the existing drop-outs to install these onto them. I will also need Torque arms though.
 

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The drop outs arrived fairly quickly along with a bunch of other stuff. I also placed orders for what I believe to be the remaining items that I will need to complete this build. Most are coming from abroad; China and the United Kingdom, so I don't know when they will get here ,but, it gives me time to get everything else done and maybe actually finish the HardRock build.

On to the drop outs.

They arrived and I am very satisfied with them. They are from a defunct bike company called Mountain Cycle Battery that built some really ugly down hill bikes. They only cost $26.00 so at that price there was really no reason for me to make a set from scratch. As I stated earlier, I will definitely need Torque arms but that will be a matter for later.

here they are:

Drop outs 1.jpg

Drop outs 2.jpg

Airplane stripper works great for the initial cleaning:

stripped.jpg

The scariest part of the build so far was cutting the drop-outs. There is now no going back.

Hack job.jpg

This is a preliminary fitting that is kinda-sorta how they will look:

prelim fitting.jpg

I have the Giant DH Comp Build by Doctorbass bookmarked and I have read it quite a few times. I have some Scotch weld DP420 ordered (that crap is expensive) and I hope that it is the right one. In his post Doctorbass writes that he used DP460 but the picture of his work shows a double syringe of DP420. The shear strength is the same at 4500 psi and I will be bolting and epoxying 1/4 inch steel carriers to the actual rear swing-arm that the drop-outs will bolt onto.

Right now I have it all in my head and drew it out quickly. there is a bit of fine tuning to do. that's all for tonight.
 
It was a super nice day out today and Mondays are reserved for special projects in the business and I only had 2 quick jobs to do so I was able to enjoy the beautiful day at the beach. It was far too nice to hang out in the basement working on the dropouts so that had to wait until the sun set. I rode around in Bradley Beach which is only a few Blocks from my home. I am a total of 11 blocks from the beach:

Beach 1.jpg

Beach 2.jpg

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HardRock B Beach 2.jpg

Then into Asbury Park. There has been a Madam Marie in this little building forever. I used to come down here when I was 5 (before the Asbury riots destroyed the town) and I remember Madam Marie. Springsteen even mentioned her in one of his songs.

Madam Marie.jpg

I did manage to get a little work done on the dropouts for the DH Comp. Believe it or not, this one is 90% done and the next one will be easy since I can use this one as a template.

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Dropout outside.jpg

I did receive the Scotch weld 420 so as soon as I finish the dropouts I can head full steam into putting it together. I have a bunch of parts ordered. pedal, seat post, headset, tab insulators for the positive side of the batteries (which still have not arrived), fork protectors, custom graphics for both the Specialized and the Giant, 72v 1000w controller, front 20mm thru axle hub, another IRC GP1 2.75 x 19, and a slew of other parts.

The front hub is coming from Czechoslovakia and is taking a long time to get here and I need it before I can order spokes. It is just one thing after another.

I have finally decided on paint schemes for the bikes. the HardRock will be royal blue metallic with white highly reflective graphics and black accessories. The DH Comp will be Pearl White with blue custom graphics and blue accessories.

I hope they look as good as I imagine them. The only thing after the Drop outs is a custom battery box for the Giant. I haven't really given it much thought yet but it is high time to think about it.

That's it for now
 
Ch00paKabrA said:
... The front hub is coming from Czechoslovakia and is taking a long time to get here and I need it before I can order spokes. It is just one thing after another....
oooohhh.. they call it Czech Republic for the last 12 years now. i was critizised very hard once when i called them czechoslovakians lately. even though that's what they have been for the longest part of my life ;)
but don't ask me why they devided and what for (same goes for former Yugoslavia). if you don't live there you it's hard to understand the background. it's strange: we share a big part of our border with both former countries, and still i know so little of them.
 
The hub finally arrived from the... Czech Republic (thanks izeman). So I can order the spokes.

20mm front hub.jpg

I managed to finish one of the drop out brackets. It came out very well considering my cad software is a piece of cardboard, a sharpie, and a pair of scissors and my "laser cutter" is a hack saw and a couple of files.

Dropout and bracket 1.jpg

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Dropout and bracket 3.jpg

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This is a preliminary fitting. The bracket will be held in place by 3 bolts and scotch weld 420 black.

Preliminary fitting.jpg

This shot shows the swing arm is about 2 inches longer. The tire and rim are fairly wide so this will move them back into a wider part of the swing arm.

View attachment 1

Wednesday, Thursday, and Friday are my busy days so I am not confident that anything else will get done over the next few days. That's about it so far.

'Cal
 
Hi ... nice beginning

Did you check the clearance of the chain regarding the lower part upper surface of the swing arm :?:
It’s difficult to say from the picture but to my point of view the wheel axle is too low regarding the origin position :?
 
looking good. you can make some nice looking things with a drill and a file. it just takes more time.
don't forget to install the axle before to define the final position of the dropouts. even minimal wrong position of the brackets will make it impossible to install the axle afterwards. dp420 and 3 bolts should give a strong combination. i think the bolts alone should do it.
 
Le Gobbi said:
Hi ... nice beginning

Did you check the clearance of the chain regarding the lower part upper surface of the swing arm :?:
It’s difficult to say from the picture but to my point of view the wheel axle is too low regarding the origin position :?

I am aware of that. I may have a problem in the lowest gear. If this is the case, I already figured out a remedy. I will need to use a tapered slider like they have on the back of dirtbikes. It will be a bit more complicated, but I know I can compensate.

izeman said:
looking good. you can make some nice looking things with a drill and a file. it just takes more time.
don't forget to install the axle before to define the final position of the dropouts. even minimal wrong position of the brackets will make it impossible to install the axle afterwards. dp420 and 3 bolts should give a strong combination. i think the bolts alone should do it.

Before I epoxy it or even drill the holes in the aluminum swing arm, I intend to mock it up with the rear wheel fully built. This set-up will have an extra 5mm in width over the standard 135mm so I think I should be able to get a 9 speed freewheel on it with spacers. I am not ordering the shifter until I see how much space I have.
 
A few more components arrived yesterday. The parts bin is really starting to get full. I now have more components than I have time.

The graphics for the Giant came from Fatmans_stickes on ebay. I think they look pretty good.

Giant graphics.jpg

The pedals also came in as well as the rim strips for the prowheel rims:

Rock Bros Pedals.jpg

rim strips.jpg

I am expecting a few more components this coming week. I actually have everything for the HardRock and just need to make a decision on the battery case then strip it, paint it and put it back together. Maybe either this week or or the coming weekend I can put that one to bed.
 
I had my first major set back today with the builds. I was running my little bafang 36v 250w motor on 72v 500w and it would tend to heat up a bit. not too bad but just very warm to the touch. I ordered a 72v 350w controller to see if that would take care of the heat. I received it and went about setting it up. The controller came with a self learning function so basically you plugged shit in and it was supposed to figure it out and make it run.

I finished setting it up and plugged everything in and then plugged the two self learning wires together and the bike just friggin flew across the basement into the wall. It was a holy sh!t moment. but then the rear wheel kept trying to spin and fried the clutch. the motor spins like crazy but the wheel won't turn. I thought it might have shear the teeth off of the gears but when I took it apart, they were intact.

I got the motor for the DH Comp back from painting so I laced it up into a spare 24 inch rim I had laying around. Tomorrow I will see how fast a MAC 6T on 72 volts will go. Gotta order a new clutch - Dammit
 
What a busy busy day! I managed to get all of my work done for the week but suffered a mild case of heat exhaustion. I submerged myself in a bath tub filled with cold water and that woke me right up.

I took some pics (I know this is not a very popular thread but it's all good) of the beach just prior to the 4th. Usually it is packed until almost dark because this is a popular week for the "bennies" to take off and hang out all week. I guess the tropical storm must have spooked them.

Bch1 7-3-14.jpg

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While I was out, I noticed this on a sidewalk with a sign that said "free!" so I took it. My niece and nephew are coming up this weekend for a month and I found another freebie BMX a few months ago so they will have bikes to ride while they are here. After they leave, I will donate them to a Catholic Charity that does very good work.

freebie.jpg

There was actually enough time today after I cooled down to finally finish the drop-out brackets. I know they are not cool CAD pieces cut out with a water jet or laser jet but I think they came out all right:

Drop out brackets.jpg

I also cut the existing drop-outs off and ground the bosses off of the outside so the brackets will fit flush. This took hours!!! It sucked while doing it but I am pleased with the result.

Brake side.jpg

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The last hing for today was to mock it all up to see if I screwed it up. Measure twice; cut once turned out to work in my favor as it looks good. the axle is a good 2 inches back but only about 1/2 inch lower so I am hoping that the chain clears it in high gear. I did the mock up with the small motor that I just fried the clutch in.

Mock up brake.jpg

Mock up drive.jpg

Mock up rear.jpg

It took a little fine tuning with a file but they are perfect. tomorrow, I hope to drill and tap the holes and maybe get this put together.

I did cut the serial number off of the brake side before hacking up the dropout. I intend to epoxy it somewhere on the bike after I file it down and make it look like a "number plate". I have a receipt for the frame so I want to be able to ID it if it gets stolen.

That's all for now.

Good night
 
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