GCinDC's Giant DH Comp

[GCinDC]

finally upgrading from the GT idrive i've been riding since '09...

picked up the dh comp a couple months ago, and have been waiting patiently for kiwi's dropout adapters. they should be ready soon, so i better get this thread going...

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and fooling around w/ it before the conversion:


so getting to work, scavenging every centimeter in the triangle...

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playing with geometry. fresh lipos - i decided to go 20s2p, to use same charger setup, but wishing i went 24s. already have 45A 72V controller (was a spare).

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another_thought.jpg (90.53 KiB) Viewed 8141 times

i'm going to use the metal track for the batt case, and cordura for a waterproof cover. and some kind of loop/handle that i can easily lock w/ frame against bike rack.

still not sure if i wanna use the hs3540 or the 9x7 9C. or eventually get a MAC. the idea was to have this a lightweight, high torque, low speed dirt bike, in addition to GT high speed commuter, but i know i'll want to commute on it...

and i'm looking for fat rims, such as the sun ringle double track. and the rim on the hs3540 is nothing special. i know i shouldn't jump that hub, and the bearings already sound crunchy. anyone know of what i can get to upgrade the bearings on the hs3540?

the rear shock (manitou swinger 6 way) is dog doo - has a crunchy spot and sag like an old lady - so i'm looking for an upgrade/replacement. don't really want to pay top dollar, as i'm most concerned w/ bottom out protection. i'm thinking fox dhx 4 or 5 w/ a 600+ coil.

front forks are ok, but could use a service. wished i'd done it already. the bike was used in utah for 3 years by a college kid. and he definitely used it.

not sure if the rear brake caliper will fit w/ the hub. hope so.

[chroot]

1st post

Look awesome setup .

[Brentis]

Good start.

Looks like a lot of travel on the rear
Sure suits your style of riding.
Impressive video making.

keep up the great work.

P.S.
What church is that in the background @ the end of vid.
While not religious, I appreciate great architecture, and that is a beaut.
would like to do a little research on it.
Thanks.

[GCinDC]

thx.

GWhat church is that in the background @ the end of vid.

Washington National Cathedral, slightly damaged by 'earthquake', and then a giant crane fell over, visible in fact in this, earlier vid:

locusts, next...

[Lenk42602]

thx. ....locusts, next...

actually, my sources tell me it begins to hit the fan ths march......

[Duc998]

Anyone know if the falcon ev bag would fit this dh comp? Im looking at having my 9 5ah zippys in the frame. I can buy a dh comp second hand medium size frame but holding out till I know if the faclon bag would fit.

Thanks

[GCinDC]

Anyone know if the falcon ev bag would fit this dh comp? Im looking at having my 9 5ah zippys in the frame.

9? as you can see, i can fit 8. my dh comp is a medium.

the bag seems large but obviously can compress too: as in this thread.

i've search high and low for a dh bike w/ room and the triangle and this is it, unless you're ok w/ an XC bike with < 4" rear travel...

[full-throttle]

Nice ride! Looking forward to the videos

the rear shock (manitou swinger 6 way) is dog doo - has a crunchy spot and sag like an old lady - so i'm looking for an upgrade/replacement. don't really want to pay top dollar, as i'm most concerned w/ bottom out protection. i'm thinking fox dhx 4 or 5 w/ a 600+ coil.

Crunchy spot? Sure it's not the bearings? Those shocks are meant to be pretty good. Have a read at the manual and play around with the settings. Sag should be 20-30%, so you may need a new 2.8" stroke spring. Back off both of the compression screws and adjust the rebound to where riding it feels somewhere in between pogoing and sticky. You can adjust the bottom out protection by adding more air pressure, lowering the air volume and increasing HSC damping

[GCinDC]

yo FT! i love it when you talk dirty.

by crunchy i mean: under constant pressure, the rear sags and inch, then stops, seems to get hung up, but with continued pressure suddenly drops another couple inches quickly, and then continues to compress steadily until it approaches the bottom.

i can play with it some more, and will start by increasing the pressure. my high pressure pumps leaks when i unscrew it to disengage, so never sure how much pressure is left. i guess i can use a separate gauge.

anyway, from reading up a bit on this most complicated subject, i'm thinking a higher lb coil might be in order, considering the extra weight on the bike and the drops i intend to do. it's nice to have quick response over smaller bumps, etc, but i'm happy to sacrifice a lot of that, but certainly not all of it, for whatever is required for big hits. any suggestions in that regard would be much appreciated. i mean, i'll surely do trails etc, but not proper downhill with the bike...

and come on, the fox dhx has 'bottom out protection' AND a boost valve!!!! (whatever that is)

[Andje]

If you want a learned opinion on your rear shock, MadRhino wrote out some good rational encompassing rear dh shocks and our heavy hub motors. I can't find it, but I know he's in a position to understand the reasoning behind the best combo of all the different features available.
I'm excited how many of the older respected members are jumping on the DS DH train! Can't wait to see you tearing down the wrong lane on this beast.

[full-throttle]

under constant pressure, the rear sags and inch, then stops, seems to get hung up, but with continued pressure suddenly drops another couple inches quickly, and then continues to compress steadily until it approaches the bottom.

Sounds like the SPV "platform damping". It's there to make the bike more pedal-able. DHX "boost valve/propedal" has similar circuitry. You cannot get rid of it completely, but can lessen the effect by increasing the air chamber volume and decreasing the pressure in the air chamber to 50psi (careful not to go any lower as the IFP will aerate). Doing this will also decrease bottom-out protection, so more HSC and/or stiffer spring might be needed.

The shocks are pretty much divided into the ones that have platform damping and the ones that don't. I'd say adjustable HSC damping is more important on e-bikes, especially for doing drops. On Fox DHX series it's the RC4 that offers that. Of course you can always add an extra shim or two to the compression stack

Anyway.. The bottom line is your shock is most likely fine, just needs a bit of dialling.

[GCinDC]

thanks, FT. you're gonna make me learn this stuff, aren't you...

this phrase is causing a short circuit in my brain at the moment:

increasing the air chamber volume and decreasing the pressure in the air chamber

i wasn't going to say anything the first time you mentioned but now... <smoke from ears...>

Im looking at having my 9 5ah zippys in the frame. I can buy a dh comp second hand medium size frame but holding out till I know if the faclon bag would fit.

not sure the size of zippy's but these are the Turnigy 5s 20c 5Ah packs, (148x49x42), and a powerpoint file to play with. right click and ungroup to move bricks around..

giant_dh_comp_med_triangle_layout.ppt

(590 KiB) Downloaded 119 times

[Duc998]

Thanks GC,

Looking at the pic "another_thought" u posted I'm hoping my zippy 9th zippy will in that open triangle space you have left. My setup is 18s3p ( zippy 5ah 6s dimensions 148x51x51mm ). fingers crossed

I've ordered the falcon ev bag and may try and get it adjusted for the frame.

Still a bit of a noob, This is my second build and just started ebikes a few months ago. Hyena has done my setup. Great bloke

[GCinDC]

Hyena has done my setup. Great bloke

sweet. he'll hook you up. i'm a big fan. he's saved my ass a couple times.

waterproof cordura for batt cover arrived in the mail, enough for a couple projects, local slackers, etc..

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[Duc998]

ok noob question here and I know I might get a few funny looks here

here it goes..... Are you going to put a kick stand? ...

My reason for this question is when I commute to work I dont want this bike accidently falling on its side with the battery pack, CA etc etc. Will be
securley parked at work in a secure bike locker room. But other riders may bump the bike.

[GCinDC]

Are you going to put a kick stand?

Thanks for a good laugh. No. My comfort bike had a nice one, but I'm sure there's nowhere to mount one on a DH Comp!

Quite hazardous I'd imagine on a rough downhill track. Hyena, got a solution? Plaster it w/ High Voltage stickers so no one touches it?

I park against walls or poles. My tires are too big to go in racks... No one messes with it. But I don't leave it anywhere it can fall over.

You remind me I will need some sort of mud guards/fenders.

[Hyena]

still not sure if i wanna use the hs3540 or the 9x7 9C. or eventually get a MAC. the idea was to have this a lightweight, high torque, low speed dirt bike, in addition to GT high speed commuter, but i know i'll want to commute on it...

I think the larger DD hubs will be tough to beat for offroad use and torque when you can just dump a heap of current into them. Macs, although geared and a little more torquey amp for amp can only take so much current before they'll eat shit. I just got a mac and it goes pretty well but it isn't comparable to my 9C. Granted the 9C is running double the current but it can take it and the mac can't. So while people will argue that geared motors have better torque, that's only true to a point. Plus given how you like to jump your bike I think you're asking for trouble with the moving parts inside the mac - the gears and clutch will likely give you grief.

anyone know of what i can get to upgrade the bearings on the hs3540?

We requested better bearings in our custom batch of 5400 motors and these would fit the HS's as well.
Just measure the size of the bearing (or search here, I'm sure someones posted it) and find a brand name unit to replace it with. I'm using Japanese NSK ones but can't remember the model.

Hyena, got a solution? Plaster it w/ High Voltage stickers so no one touches it?

High voltage stickers ? Nah, but a Jacob's ladder kit that arcs electricity up the spokes should do the trick
The magnets in my motor are actually so strong it just sticks itself to poles when I lean the bike there
(I joke of course)
I do have a double legged stand (like pictured below) I was going to try and fit to my stealth fighter but I'm not sure I will now.


I used to be a bit annoyed that better quality bikes didn't come with kick stands like cheap ones do but you get used to finding somewhere to lean them.
A heavy ebike balanced on a flimsy kick stand is probably more likely to fall over if someone bumps it or with a gust of wind than if you take the time to lean it properly against something solid.

[GCinDC]

I think the larger DD hubs will be tough to beat for offroad use and torque when you can just dump a heap of current into them.

ok, fair enough. discussion over. i'm sure you and knoxie are right, and whoever else has been trying to pound the same point. I'm sure it's not a matter of IF i were to destroy the MAC gears but when...

now deciding between a 9C and hs3540 is gonna be tough. partly depends on what becomes of GT idrive.

increasing the air chamber volume and decreasing the pressure in the air chamber

ok, FT, let's work this out: it's not possible to increase the chamber volume, right? if the chamber is, say, 100cc, that size will not change (except when under compression), so one can't increase or decrease the chamber volume at rest, right? i would have guessed that you meant 'increasing the air chamber pressure' , but then you follow with 'decreasing the pressure...' hence my confusion.

i guess the only way what you're saying makes sense is if the chamber size is truly variable, as it may be with the internal plunger or whatever it is, but that would be done by adding air, and consequently increasing the pressure.

regardless, the dang shame is that i need to remove the shock from the bike, or at least remove the bottom mounting hardware in order to even see the air valve. so 'dialing' is gonna require a lot of assembly.

thx. ....locusts, next...

actually, my sources tell me it begins to hit the fan ths march......

end of the world stuff? link?

[full-throttle]

GC, both SPV and DHX have position sensitive compression damping with the ability to adjust the internal air chamber volume and pressure

• SPV Air Pressure: The air pressure that controls the SPV compression damping qualities and
characteristics. More air pressure creates a firmer platform and increased compression damping. Less
pressure creates a lighter platform and more supple response.
• SPV Volume Adjustment: The volume adjuster located on the SPV shock reservoirs. This adjuster controls
how firm and progressive the position-sensitive compression damping feature acts. The smaller the volume
in the SPV chamber, the more progressive and position sensitive the compression damping becomes.

spv.jpg (83.71 KiB) Viewed 3459 times

Hope this helps

From what you described before your shock is either set to be very progressive or it may have faulty internals (hope not)

[Duc998]

Thanks for a good laugh. No. My comfort bike had a nice one, but I'm sure there's nowhere to mount one on a DH Comp!

Quite hazardous I'd imagine on a rough downhill track. Hyena, got a solution? Plaster it w/ High Voltage stickers so no one touches it?

lol I've never had a quality bike but guess I will get used to it told u I'm a noob . But those high voltage stickers aint a bad idea

Pickup my DH Comp tomorrow morning, Cant wait. First thing I'm going to do it see if I can fit my pack into the triangle. Was up till 2am last night
searching through ES for DH comp build and loved Doctorbass's badass build... But wont be going anywhere near those specs... I'm using the same 6s zippy's as Doctorbass's, Mine are 25c he's are 20 - 30c could'nt find the exact C rating in his thread, I've attached one of DocterBass's DH comp pics and looks like I'll fit the 8 zippy's but the 9th will be difficult, Sure I'll work something out. I'm lucky I've got hyena's backup and he's not too far away

I'm on the second run for kiwi's dropouts, Have you gotten yours yet? Look like I'll have to wait a few weeks for those...

Cant wait to see more update's on your build GC

cheers

DoctorBass DH Comp build ( hope u dont mind Dr )

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[GCinDC]

Pickup my DH Comp tomorrow morning, Cant wait. First thing I'm going to do it see if I can fit my pack into the triangle. Was up till 2am last night searching through ES for DH comp build and loved Doctorbass's badass build...

good luck getting your bike. i recommend you study it w/ a fine tooth comb before forking out the cash. i studied every inch of mine but still find dings and things i hadn't noticed the first time...

regarding searches on ES, be aware that search terms must be > 3 characters, so a search on DH will turn up nothing... there are now many threads on DH Comp conversions/resources. here are some that i'm aware of:

----WAYNE'S GIANT DH----
Buying 04 Giant DH Comp
Giant DH Comp Drop Out adapters and conversion
Repository for 3D Part Models, Drawings & Schematics
Giant DH Comp - Damageless Torque Arms…
Keyne's DH Comp Build - now with VIDEO!
PROJECT no 4 Doc's Giant DH comp 2003

and soon you will start your thread.

Hope this helps... From what you described before your shock is either set to be very progressive or it may have faulty internals (hope not)

beautiful pic, FT. that does help. you almost convinced me to love it despite all the trash that's talked about it, but i have a gut instinct about it and snagged a used FOX DHX 4.0 that was going wicked cheap on eBay last night.

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i'll play with both and keep the one i like.

the real question with these shocks is: what's the best setup for my kind of riding, since power pedaling won't be required? or perhaps, put differently, what would be the best way to set up the shock so it performs like the rear shock on a motocross bike?

[GCinDC]

lowbrow for most, but works for me...

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i'm trying to decide now where to mount the connectors, and therefore how to cut the front of the box. i could cut the box so it wrapped tight around the batts, but then there would be nowhere safe to bolt, as the bolts would penetrate and hit the batt. so i can leave a couple inches in front, and also fill that with wires for the connectors, but will i want to mount the connectors facing forward or to the side? to face out, they connectors would have to be inset a lot, so they don't stick out...

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i'm tempted to face the connectors forward this time. they would be harder to use while the pack is mounted on the bike (unless i were left handed), but i'll bulk charge when the batt is bike-mounted, so won't have to unplug the big plug. And to balance charge, i'll probably remove the pack (to bring it indoors), in which case the connector will be on top, and easy to insert/remove.

another concern would be water, but i can cover the connectors with a sheet of cordura, velcro'd to both sides, either of which i can lift, to access the connectors.

this is how i'm thinking of doing it now, but i'll need to decide on the lockable loop/handle that i'll bolt on to the front as well. my old one is a 1.5" wide piece of aluminum sign, but it's not the most ergonomic handle (too wide and flat), and i could do it much thinner in steel, especially as that will leave more clearance to access the connectors...

[Alan B]

Cromotor.

[Doctorbass]

Thanks for a good laugh. No. My comfort bike had a nice one, but I'm sure there's nowhere to mount one on a DH Comp!

Quite hazardous I'd imagine on a rough downhill track. Hyena, got a solution? Plaster it w/ High Voltage stickers so no one touches it?

lol I've never had a quality bike but guess I will get used to it told u I'm a noob . But those high voltage stickers aint a bad idea

Pickup my DH Comp tomorrow morning, Cant wait. First thing I'm going to do it see if I can fit my pack into the triangle. Was up till 2am last night
searching through ES for DH comp build and loved Doctorbass's badass build... But wont be going anywhere near those specs... I'm using the same 6s zippy's as Doctorbass's, Mine are 25c he's are 20 - 30c could'nt find the exact C rating in his thread, I've attached one of DocterBass's DH comp pics and looks like I'll fit the 8 zippy's but the 9th will be difficult, Sure I'll work something out. I'm lucky I've got hyena's backup and he's not too far away

I'm on the second run for kiwi's dropouts, Have you gotten yours yet? Look like I'll have to wait a few weeks for those...

Cant wait to see more update's on your build GC

cheers

DoctorBass DH Comp build ( hope u dont mind Dr )

DocsDHComp.jpg

Yes they are zyppy 20C but the 25C fit perfect also.
I now have 15 packs ( 30s 3p) that fit in the triangle. The 3 added packs are horizontal position and their lengh is equal to the width of the 3 pack wide box.


Doc

[Doctorbass]

For those who would like to have some idea of the motor-swing arm installation that Bison_69 have done ( open source), here is two file you might appreciate!