PROJECT no 4 Doc's Giant DH comp 2003

Doctorbass

Doctorbass

100 GW
Joined
Apr 8, 2007
Messages
7,496
Location
Quebec, Canada East
A guy is offering me a DH bike that is interesting me for an ebike project.

He accepted to drop his price from 900 to 700 CAD$

I love the simple suspension desing and that it still leave enough room for Lipo battery in the frame and that the swing arm seem having very strong pivot

Any opinion regarding this bike???

Here it is: http://www.lespac.com/d-sports-loisirs-velos-boischatel-giant-dh-comp-2003-a-vendre-LPCaZZ21679486

21679486-0-1273534027.jpg


-Bearing and bushings are brand new.
-8 inch rear and 7 pouces on the front boxxer
-Shimano xt 4 pistons brake,
-Wheels mavic 729 using marzocchi for front wheel.
-Recommanded for a person of 5'10" or more.
The orignal bike look like:


Doc
 
Looks like it has ample space for batteries in the triangle. Nice choice.
 
Hi Doc,

Great bike, the Boxxer "race" fork is normally around 500 $ CAD (Fork only, no hub, no rim) it's not the best fork an ebike but your are lighter than me and it can do the job for you, and you can upgrade it or changed it later if needed. The Shimano XT with 4 piston has great stopping power, I love the design of the suspension, and is a great base for an ebike project no doubt about that my friend :wink:

Good day!
Black
 
Yes, It is very good bike, show us pics and vids. When you complete your new ebike. :D
 
Thanks guys for all recommandations! :mrgreen:

I finally bought it. I will need to custom make an adaptor for the rear drop out ( it's 14mm dia axel room and not 10mm like usuall.) i'll ask CHXS's father to make me a machined steel adaptor that will also act as torque arm.

i'm still not decided if i convert it to 24" wheel that i really love! ( like the stealth bomber) or if i keep the 26" wheel.

iT's ghard to find a goos rear 24" rim that fit 36 holes and that is strong! and wide ( 30mm+).. I know Alexrim make some but thet seem not thick enough for me..

Doc
 
voicecoils said:
Nice.

What motor do you plan on putting on it?
Click to expand...


I plan to swap my 5305 from my mongoose to that new Giant DH probably with a 24" wheel.

I'll install the 5303 20" on the mongoose.

I still dont have figred out how to soften the rear suspension coil ....do i need to take appart the rear shock before to rotate the spring sleeve?.. The spring is loaded alot! and the sleeve just dont rotate...
 
I'm very interested in how you plan to mod the dropouts to fit the motor.


Kurt made vertical dropouts in my frame (see Voicecoil's first build thread - the frame was his then).


But there are things I would change if doing it over.


The dropouts are really thick. 15mm each side, with a 140mm spacing. Getting a motor with a long enough axle was an issue. My MAC, with a 205mm axle, has BARELY enough thread for the nuts. No room for spring washers.


And the wheel worked loose once (it's now got locktite).


I would try and make the torque plates closed around the axle, and removable with the wheel, and only 3 or 4mm thick (unless your axle is super long). Not sure how easy it would be to get the wheel off with the derailleur in the way, but worth thinking about.



To remove the spring, take the shock out, and unwind the spring preload collar. When it's loose it will become clear how to remove it. It shouldn't be stuck.


If your shock is the same as mine it will have about 20 adjustments....good luck with that.....
 
Doc, speaking of a 24" rim, I just bought a 5305 from Maxwell to go on my Karpiel Disco Volante DH. I too was thinking about 24" rims with a SuperEtard I mean Motard look. I was wondering if anyone has used a Halo Combat2 rim with the
12 Guage spokes? The Halo is super tough, but it has stainless inserts in the spoke holes, don't know if they might need to be drilled or what.
 
Seriousknot said:
Doc, speaking of a 24" rim, I just bought a 5305 from Maxwell to go on my Karpiel Disco Volante DH. I too was thinking about 24" rims with a SuperEtard I mean Motard look. I was wondering if anyone has used a Halo Combat2 rim with the
12 Guage spokes? The Halo is super tough, but it has stainless inserts in the spoke holes, don't know if they might need to be drilled or what.
Click to expand...

Usually to fit 12 gauge spoke Yes you must drill the eyeslet. The 12 gauge nipples are larger.

That Karpiel is a nice bike!


Doc
 
Nice frame doc !!! and i agree with the 24" rims, damn hard to find but they are out there.

I've been ripping around town on the BMX lately and i miss the norco's full suspension alot.. i'm swamped with work but have the norco 75% done... waiting for the lipo hehe..

I managed to retain the eyelets on some rims by using a round file ( used to sharpen chainsaw teeth !! ) takes time and alot of elbow grease but 12g nipples can it in eyelets with enough determination, uhhh.. actually... now that i think of it radial spokes may only be possible with eyelets, for 1 cross the eyelets may have to go completely.. :|
 
Doc

Just some more random thoughts about the frame.


Mine has an odd 90mm bottom bracket. I have a Shimano Hollowtech 2 fitted. So all I have to do to replace it is buy any other hollowtech 2 BB and reuse the centre spacer.

Yours looks to have a Truvativ Howitzer or something.

All I'm saying is you may have trouble finding a replacement when the time comes.



Also, the frame came with either 135m (mine is really 140mm) spacing, or 150mm spacing at the rear. Which has yours got?



Oh, and I drilled the eyelets in my rim for "ebike style" 12GA spokes. And they were complete crap compared to decent 14GA ones.
 
Ypedal, Nice setup to come!.. I agree, 24" rim = not easy to find in local store!

Mark_A_W, My dropout is 135mm. That's my first DH bike and the frame is made of different stronger parts so i need to learn.

The rear dropout piece seems very strong and i'm confident that i'll find a great way to fit that X5 beast!

It's almost clear that i'll fit some strong and wide BMX style 24" rim

Doc
 
Doctorbass said:
Ypedal, Nice setup to come!.. I agree, 24" rim = not easy to find in local store!

Mark_A_W, My dropout is 135mm. That's my first DH bike and the frame is made of different stronger parts so i need to learn.

The rear dropout piece seems very strong and i'm confident that i'll find a great way to fit that X5 beast!

It's almost clear that i'll fit some strong and wide BMX style 24" rim

Doc
Click to expand...

I would not run 24" on the DH Comp or DH Team (I already tried). The bike rides pretty low that way (even with fat tyres).

The bottom bracket will become too close to the ground. If you use a heavier weight spring and run the suspension stiff with minimum sag, it might be OK just on the street but you still may strike your cranks in turns.

If you're building a very powerful bike, why not just take the motor to a friendly motorcycle wheelbuilder and have them lace a moped rim to your X5 with 10ga stainless motorcycle spokes.

Or buy a good 26" DH rim and buy the good stainless 13ga spokes from ebike.ca
 
Interesting.

I'm running a 600lb spring, and the pedals have never come close to hitting the ground, with a normal level of caution - with a 26" rim and fully inflated hookworms.


I would have said it would be fine at 24", with fully inflated bigarse tyres.


It will also depend on the fork setup. I did have pedal strike issues on my mongoose dually, when I have the forks set 40mm lower than normal (triple clamps), on a 26" wheel. Lifter the triple clamps back up to the top of the staunchions and it was fine.
 
Mark_A_W said:
Interesting.

I'm running a 600lb spring, and the pedals have never come close to hitting the ground, with a normal level of caution - with a 26" rim and fully inflated hookworms.

I would have said it would be fine at 24", with fully inflated bigarse tyres.

It will also depend on the fork setup. I did have pedal strike issues on my mongoose dually, when I have the forks set 40mm lower than normal (triple clamps), on a 26" wheel. Lifter the triple clamps back up to the top of the staunchions and it was fine.
Click to expand...

You've got your setup really stiff, DH bikes are often set to sag 20% just sitting on them. Think Dmitrii's bike. You're on 26" rims and the hookworms are a pretty tall, fat tyre. Basically your set up to be as far from the ground as possible.

I think you could make it work on 24", but I don't see massive benefits in using that size wheel to compromise other aspects of the bike just to use them. There are very strong 26" rims and if you want more "thrust" just increase the current limit on the controller instead of downsizing the wheel size... Just my opinions.
 
voicecoils said:
Mark_A_W said:
Interesting.

I'm running a 600lb spring, and the pedals have never come close to hitting the ground, with a normal level of caution - with a 26" rim and fully inflated hookworms.

I would have said it would be fine at 24", with fully inflated bigarse tyres.

It will also depend on the fork setup. I did have pedal strike issues on my mongoose dually, when I have the forks set 40mm lower than normal (triple clamps), on a 26" wheel. Lifter the triple clamps back up to the top of the staunchions and it was fine.
Click to expand...

You've got your setup really stiff, DH bikes are often set to sag 20% just sitting on them. Think Dmitrii's bike. You're on 26" rims and the hookworms are a pretty tall, fat tyre. Basically your set up to be as far from the ground as possible.

I think you could make it work on 24", but I don't see massive benefits in using that size wheel to compromise other aspects of the bike just to use them. There are very strong 26" rims and if you want more "thrust" just increase the current limit on the controller instead of downsizing the wheel size... Just my opinions.
Click to expand...

Thanks for these comments voicecoil.
I just like the look of twin 24" wheel on mtb or DH bike. it add considerable trust and it's a bit less hard on the troque arm ( lower torque on it for the same trust)

Also I want to add some clearance under the frame and the front wheel to add 12x 6s 5000mAh lipo packs.... or some A123...

I want lower center of gravity as possible.

thanks for your advices anyway. btw.. it can't be worst than mo mongoose actual setup.. 20" rear and 26 front.. and.. 128 pounds.. I need to keep pedal up when i turn with that ebike...

Whre can find a 600pounds spring for that manitou?.. I actually have a 400 x 2.75.


Doc
 
I like the way you think Doc, 24" will look cool. You could always switch to 170mm crank arms, only slightly less leverage, that is, if you plan to pedal.
 
Hey Doc,
I just noticed that A123Systems has a job opening for a Quality Technician at the manufacturing facility in Michigan. Ever thought about immigrating? The job might be a step down for you, but we could really use a man like you on the inside.
 
Seriousknot said:
Hey Doc,
I just noticed that A123Systems has a job opening for a Quality Technician at the manufacturing facility in Michigan. Ever thought about immigrating? The job might be a step down for you, but we could really use a man like you on the inside.
Click to expand...


Thanks!.. interesting job..! I guess my cell testing experience would be a must :wink:

I wonder what cost of living in michigan could be...

I also had a job opportunity from a major distributor of BionX product here in Canada for technicalk support... but i already have a nice job that i really love here... it's in R&D to and we also work with aerospace optical technology projects.

so from now.. if someone is interested, we have two excellent job opportunity here:

-A123 system in Michigan: Quality Technician
-BionX in Quebec city : technician support


Doc
 
Doctorbass said:
Whre can find a 600pounds spring for that manitou?.. I actually have a 400 x 2.75.


Doc
Click to expand...


Chain Reaction Cycles (CRC).
 
voicecoils said:
You've got your setup really stiff, DH bikes are often set to sag 20% just sitting on them. Think Dmitrii's bike. You're on 26" rims and the hookworms are a pretty tall, fat tyre. Basically your set up to be as far from the ground as possible.

I think you could make it work on 24", but I don't see massive benefits in using that size wheel to compromise other aspects of the bike just to use them. There are very strong 26" rims and if you want more "thrust" just increase the current limit on the controller instead of downsizing the wheel size... Just my opinions.
Click to expand...

Dmitrii's was more like 80% sag...

He's now changed from a 300 to 450lb spring.

We aren't downhilling on these bikes, we're pissfarting about at high speed on ashphalt. I could go an ever stiffer spring :)


The ride is better on 26". 24" looks cooler.

But pedal strike is bad news, I'm staying with 26".


Doc, for perspective, I weight 90kgs and want my bike set up pretty stiff (think sportsbike rather than downhiller).

So if you weight less than me, a 600lb spring will be too much for you.


Mark
 
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