GCinDC's new DH COMP.....project aborted

After much ahdoo & waffling (& copius finger drumming by supposedly paitent onlookers )

I present My idea of what a DH comp should look like (eventually)

A little history:
G bought a Scott dh bike in a moment of weakness & was soliciting ideas for the build...I offered to give it the full Monty thud style...& G thought about it.......then said since your offering, I'll just buy another DH Comp for you to thuderize...
can't have too many bikes in the garage....(i am not sure his wife is aware as of yet LOL!....been there done that. :lol: )

Here is the bike as I recieved it:


1st impression: Well built bike for its intended use....bombing down big ass hills & everything in the way as its doing it.....this is no bike built for cross country trail work...its a heavy muther & pedals like #@*!@t. I'll remeber to get a pre-conversion weight but I guess the thing is more than 30#s as delivered. Edit:bike weighs 46 pounds before conversion

The Plan:
Build the lightest, most durable,maintance free offroad orented e-asist we can...& for maximum utility & hill flatening ability, we will drive the bottom bracket & use the full range of gearing the stock 8 speed allows. Matching the human cadance with 2.5kw of continuous assit....peaking at 5kw for some serious climbing power....all the while the riders feet are firmly planted on the pedals & able to crank along as much as his heart desires.

I built a BB drive for a buddy a few years back....so this is not toatly new teritory....but you will see the evolution in this new project. Here is a Giant that has the 1st prototype drive in all its square box uglyness. Its powered with Turnigy 6374, a CC Ice100 running on 8cells.

It is a joy to ride....& I have mentioned this bike in a few threads, & frankly this is my ideal "assist" for a bicycle. nothing like the moped class bikes I have more recognition for....the superman feeling of riding this bike is something you have to experiance. it is still good for 25ish mph in top gear....but for hauling the kid trailer or climbing a hill....this thing is a real winner.

Here is a model of the new reduction unit, its actually the plug that will make the gear cover mold for the production unit, exact size with the exception of being 3/4" wider.
Thats right, the main reduction unit is 2.25" wide.....thats the same width as a downhill tire....& less than the 2.375" down tube of the DHcomp.

Inside that magic box resides compound #25 sprockets that yeild a 6.65-1 reduction internaly. to make the unit maintance free, I will mold the cover to make it oil tight & hold aprox 3 oz of splashy slipery stuff to make the chains happy.
sample:
[youtube]0lHB_NWZlRA[/youtube]

yep, they are machined to reduce weight...so i can bolt them to the heavyest bicycle I have ever seen

a few notes....right now the reduction unit is weighing less than 3 pounds by itself.....add another 3.5#s for the motor & another 1/2ish pound for mounts & screws...(all to be verified in time) We will be coming in at under 8#s for the unit installed.....try that with a mid mounted hub motor
the freewheeling cranks & sprockets will be a push replacing the heavy stock cranks.
it fits on the bike like this:

it almost hides behind the stock 44t sprocket....
peek-aboo the 80mm outrunner position...we may need to evaluate batery capacity, or move the motor in front of the downtube to maximise space for a 20AH pack....we'll see.

The big engineering challange for this project is the masive 2.375" downtube & the odd cast/forged 100mm wide bottom bracket welded to it.....

nothing standard about it....So I'll be fabbing a custom spindle for the cranks & such...I have some ideas for a bolt-on option for the drive unit.

I'll stop here....for now.
come up with good questions.....& please don't wast space beggin me to build your shit till this bike is finished getting the "treatment"

this is the place where I will show the motor & controller love conection:
a lil re-winding & some XieChange mojo for you mo-fo's

till i get there, here is a picture of my dogs.

custom battery box construction here:
How much battery do you think is required for off roading fun? I (edit) can't shoe horn 20ahin the fram space....but can drop a few pounds of riding weight using 15AH
Edit 2/10-13
1st battery box mock up:


after looking at this one....I am dis-satisfied. I really want the motor to nestle in the lower frame junction

lets start over & kill the day with design iterations:


This one holds 10ah of lipo & i perfer the profile & plenty of room for a controller & the motor placment
I will add a 2nd tier for the full 15ah i think G will need to tire hisself out on the trails


This will put 4 packs above the top tube...the box is a complex shape & will house all the parallel/series harness along with an anti spark circuit. the bulk of the day was spent figuring a quick release set up for box from the bike....1 hand nut & one disconect & it will unlaod from the bike in 1/2 a minute.
use your imagination & see the top tier joined to the lower & sliding over the top tube...it will swing away (prolly from the left)

box will be composite over foam construction...I had hoped to be that far today but....thats how it goes (late night watching the supercross on the west coast)
There will be nice low profile draw latches holding the covers on the batterys very clean, very water resistant.
edit: chaff removed to conserve space(?)
This white bike is reminding me of the "powerfull Mach 5"......maybe a red #5 head bage & some Speed Racer stickers?

I will post pictures of the box construction details further along later this week.

here is a shot of my hot wire saw for cutting foam.....still loving the 1010B.....thing is a work horse!

I'll just reserve this space for a summery overview & thread round up if it ever gets to that....

oh yea, greg Hates white bikes......He wants a paint Job, lets all vote.....matt black, Barny purple, pepto pink?
lets hear it!....(i would love to film dip it in digital camo!)


let the tangentail derailing begin in earnest my friends!




JUst for fun here is my cat with a small original sculpture


& my favorit casting photo....a bronze pour with a lovely zinc flame showing.

Profile Racing makes 48 spline crank spindles from chromoly and titanium, in multiple lengths up to 6-7/8" (175mm). They also make spline drive sprockets and chainring spiders that could greatly simplify the task of setting up the spindle with both input and output sprockets.

Between their ruggedness, easily adjustable chainline, long spindles available, and abundant possible configurations, for your project these components might be worth their substantial cost.

grinning ear to ear! i'm so excited.

i called todd two weeks ago to ask him about his plans and made a podcast out of it, fyi.

can i get a puppy or two with it?

badass

I'll be watching from Missouri......

Tom

Hey Greg!
Check the for sale thread for a black DH Comp :wink:
Lol is sat that's perfect timing if you hated the whit frame so much.
Can't wait to see how this performs in real life, maybe the videos you will be posting will make up for the other one?

Yeah, great build. hows about--- tubeless?, titanium(bolts, nuts, stem, etc)? carbon bars? beaver traps pedals? nano tech? XTR groupset? road bike cranks? air shock/fork mabye theres more ---but you could shave a few more pounds and still have the strength.

Im loving it !! i dont carry extra weight on myself, why would i on a bike !!, i can really appreciate what lighter weight does to handling!! offroad or in the urban jungle, its gonna make a huge difference in the feel.

Im watching, and drooling over this build

That's the ticket!

Will Gregg be happy with 25mph?

Nick

Been waiting for this thread for awhile now, jeez, hunting season must be over or something. :lol:

My vote is for purple splash over hot pink. Also, I will be careful not to leave. This thread page up on the computer, otherwise the GF will want one of stinking cute puppies!

For the FULL treatment maybe you could come up with your own head tube badge?

The head badge! I had completely forgotten the most important part....thanks for the reminder Etard!
That will be a numerator in my equation to justify building a co2 laser cnc.

There it is Greg, the copyright holder has given his blessing for Purple splash paint.....that's ultruism baby!
(I can see GC in white framed sunglasses hydro planing across the reflection pool in a video this summer!)

Chalo, thanks for the heads up on those part$....G & I will be discussing the budget
Hydro- the weight weenie part of the title was an attempt at irony....this is a heavy bike!

After my contribution, I will let G drain the kids college fund for a weight savings program....those parts are deep into diminished returns for this application IMHO.

Sorry guys...the puppies are now dogs & all off living in the world....stock photo to fill space.
The old cat is still available

here's a benign example of the hilly trails i've got that the hubbie can barely tackle with a run up, but quickly bogs down on.

i'm hoping the thudmaster comp will eat this hill for breakfast.

nicobie said:

Will Gregg be happy with 25mph?

Click to expand...

30mph is a good top end i think, esp if it's still power wheelie territory...

GCinDC said:

esp if it's still power wheelie territory...

Click to expand...

If Thud built it, I can almost guarantee it...

Weight weenie build starting with a 46lb bike? I have a Specialized FSR from 1999 that has about 4" front and rear travel and weighs around 27lbs. The thing is dialed. I can't even find a buyer for it at $350...

Very cool stuff Thud! I'll be watching this one! I love the little sprockets!

Is it built yet?? where are the vids or pics of some tire shredding? Are you going to give Greg a refund because of how cool it will be?
Btw Thud, how is the H35 stator coming along, what are your plans for that?

lest any relevant comment get lost in the wilderness (other threads), i'm reposting some recent comments here:

regarding the weight of the unmodified dh comp:

Thud said:

OMG!
46#s as it sits.......

Click to expand...

knoxie said:

grindz145 said:

Another Episode of the nerdcast is live: http://troyrank.com/2013/01/29/ebike-nerd-podcast-episode-30/

I know, an actually WEEKLY release for once?!?

You all can thank Greg and Todd for this one. I'm super psyched to see this middrive madness. To the end of the frock era!

Click to expand...

Interesting podcast, nice to hear from Thud too, Greg is in pretty safe hands there I am sure.. Thuds stuff tends to just work 8) and nice to hear he is using a sensored motor and controller, sure you will loose a bit of the poke of the RC controller experience but you will gain a whole heap of reliability, Greg mentioned at the start about Deecs bike and the infamous crash somewhere in England :lol: it was out the front of my house? I thought everyone knew that :lol:

Deecs bike was pretty unridable as he found out himself, the power of that thing was arm wrenching and he in fact took it all off and sold it and went back to a hub motor which I dont know if he ever actually got working because he had to make up the battery pack.

I think Greg will have a lot of fun, you will get very good at setting your gears and putting on new chains, the Optibike used to toast chains even at 750W so normal bike chain at 5KW will wear super quick, change it out if you get lots of skipping even if its aligned properly, have had a lot of experience of bike chain and high power buddy starting from way back with this.

Crikey we did this way back in 2004! there was a big Lemco motor bolted to this thing kicking out about 3-4KW at the time..was a hoot but the batteries werent great back then, was a real bike chain snapper, we went to fixed BMX chain in the end and fixed gearing.

Here is the reduction all nice and shiny before we let rip, I still have all this in the loft for a rainy day.

You should have a lot of fun Greg, its certainly a different experience

Click to expand...

i thought all it does is rain in england, knoxie. what's the hold up?

as far as what's new between now and 2004, it's far be it from me to say, except that it'll be mine, and i'm pretty excited about that!

anything new at the forge, thud?

nevermind about my dropping by in July, btw... i think i'll need it sooner!

also, these were up on the podcast but not here yet...

Trackman, I am short a few screws....(that didn't sound right :lol: ) no big deal though, I will prolly replace them all with freash when the time comes...promised myself to finish G's bike before I touch that hubbie.

I updated the battery box layout with freash photo's. tore apart the cranks....wound 3 motors for testing last wednsday & etched a freash set of boards for extrnal hall placment testing.

Greg, I never thought you could wait till July LOL!
I'll get some pictures of mold-less fiberglass work for the batt box this week...naybe even get the controller knocked out...still lots to do but progress is starting to accelerate

Thud said:

custom battery box construction here:
How much battery do you think is required for off roading fun? I (edit) can't shoe horn 20ahin the fram space....but can drop a few pounds of riding weight using 15AH

Click to expand...

Nice work Thud!

I find 48V 10AH to be plenty for me offroading, but I also peddle a lot.

Personally I dislike the double wide packs or packs above the triangle, but you have to comprimise somewhere I guess.

yeah, the ping lifepo 20ah pack is going to be pretty big, but if anyone can fit it in there, it's thud. :wink:

i'm just kidding. we thought we'd go a bit retro on this, so it'll be lead acid all the way!

i think 15ah will be fine!

Great, another one of Greg's silly threads I now have to subscribe to
Sweet looking build so far guys, that gearbox is one sexy beast!!

Lead acid, now you're talking! Retro cool!
Make sure you also wear thick rim riding goggles with no lenses in them for maximum hipster appeal :lol:

GCinDC said:

yeah, the ping lifepo 20ah pack is going to be pretty big

Click to expand...

I do hope your joking about using a ping pack :-| ? I pmed Thud about other 'business' this morning
and suggested possibly forgoing mounting the pack on the frame and using a back pack
with a few lipo bricks in it. Have you seen the thread a member is making a back pack setup
using a 3D printer, soz i havent got link handy...might be a neater/stealthier solution...just a thought

Following with interest anywayz...Thud will ROCKZoR this build no doubt about it

KiM

Here's the one you're talking about Kim. It is pretty sweet. I am following closely for when I do a full sus off roader.

http://endless-sphere.com/forums/viewtopic.php?f=6&t=47275

Can't wait to see the result of this bike Greg and Thud. You are really dragging out the suspense.

Clay