NEED help with Giant DH comp...- Mtbr.com
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  1. #1
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    NEED help with Giant DH comp...

    first off I want to say sorry if this isn't posted in the right topic, it seemed like the right one. I'm new to the "real" bike scene, by that I mean a bike that ISN'T meant to be tossed after the first part breaks, a bike whose INDIVIDUAL parts cost more than COMPLETE commercial bikes.

    Anyway I recently scored an '03 DH comp from a buddy. I was looking at the front drivetrain and trying to figure out what I could do about the POS bash/ guide combo that came stock on it, I don't like it AT ALL! In a nutshell, what are my options? is there any way I could get a derailleur and two rings up there W/ a chain guide? I would like the flexibility of a 2x9 as the trails I ride are more FR oriented and a 1x9 just kills me trying to pedal it anywhere ( yes, yes I KNOW!... its a DH bike)

    Right now it's got the stock RF prodigy cranks W/ a Blackspire 38t ring, and I assume the stock BB. BB shell is 100mm. Also it's got one threaded eye- like 1/3 of a set of ISCG tabs- that ( I believe) would allow something with ISCG 03 mounting to attach, at least with ONE bolt.

    Another Q: Just how vulnerable IS the bottom pivot W/O the stock Bash?

    Sorry for writing a novel, and Thanks in advance,
    Max

  2. #2
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    The DH comp is slightly problematic because of the mounting for the Stock chainguide. Due to the design of the frame, you need to do a little bit of modification to make a “normal” guide fit on the bike. There is a small tab on the driveside front of the bottom bracket shell that needs to be removed in order to allow an ISCG bottom bracket adapter to fit. This tab is used with the stock custom chainguide. Take off this tab (read: file or dremel), and the bottom bracket adapter should go right on, and installation will go as normal.

    I'm using an e-13 chainguide and bashguard on mine. I'm not sure if u can install 2 rings up front since it'll be challenging to mount a front derailleur. But I've been wrong many times before.

  3. #3
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    Im not too familiar with the frame but if you have to keep 1 ring up front you could get a 34, 35 or 36t and run it with a bigger cassette like a sram pg990 in an 11-34t
    "Ride Life Ride Giant"

  4. #4
    No Fear
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    I think the frame aint got the right mount for a Front D.

  5. #5
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    You can use an e-type derailleur (click), I guess? There are e13 guides for that aswell (e-type drs system has 2 holes for you to mount the derailleur)

  6. #6
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    You can mount an e13 on them, you'll need to use the ISCG05 adaptor and shim the BB out a hair.

  7. #7
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    yeah i just installed a e.13 st/ss on an 04 dh comp last week. He actually was "running" 2 rings. reason i say that is because it didn't work at all. It works like a champ now. it was so close to not fitting though. you def need to be careful or you'll pick the wrong chainguide. if you get the e.13 st/ss, get the iscg 05 one as it comes with the bb adapter

  8. #8
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    Ummm...

    Quote Originally Posted by nmpearson
    yeah i just installed a e.13 st/ss on an 04 dh comp last week. He actually was "running" 2 rings. reason i say that is because it didn't work at all. It works like a champ now. it was so close to not fitting though. you def need to be careful or you'll pick the wrong chainguide. if you get the e.13 st/ss, get the iscg 05 one as it comes with the bb adapter
    thanks for all the info so far everyone. I'm a little confused by your post though. Looking on the e-13 site, the ST and SS are each single ring guides, if I'm not mistaken? and the DSS and DRS which it says are for dual rings CAN"T be used with an adapter plate, correct? and the same with the DS. So I'm a little confused... did you have two chainrings and a FD, or one chainring and a bashring?

    How well would something like this work? anyone have any experience with this set up?

    thanks again -Max

  9. #9
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    Here is a pic of my dh comp. It is an e13 srs with a dangerboy bash and 36 tooth ring. I mounted it with a bb mount and one black washer between the mount and the guide. It has holzfeller cranks, sunline bars and minnion dhfs now too i just dont have a newer pic with the guide in it.

  10. #10
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    sorry i was saying just go with single ring. the problem with the dh comp is you have to really push the back wheel really close to the frame to keep it from dropping. if you look at lucas's bike...it's nearly touching. that blackspire guide may work...but i have a feeling in order to keep good tension, the derailleur wouldn't be able to work well enough. Maybe try and getting a larger cassette range, say a 12-34. then you'd be able to pedal anything from wide open dh to climbing. i'd do that and do a single ring...that's my suggestion. i think the setup would be a ton more fluid too

  11. #11
    Meh.
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    What's the BB shell width and the chainline on those? If it's more than 50mm, a FD may not be able tos wing out far enough.

  12. #12
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    Quote Originally Posted by nmpearson
    sorry i was saying just go with single ring. the problem with the dh comp is you have to really push the back wheel really close to the frame to keep it from dropping. if you look at lucas's bike...it's nearly touching. that blackspire guide may work...but i have a feeling in order to keep good tension, the derailleur wouldn't be able to work well enough. Maybe try and getting a larger cassette range, say a 12-34. then you'd be able to pedal anything from wide open dh to climbing. i'd do that and do a single ring...that's my suggestion. i think the setup would be a ton more fluid too
    \

    If your not planning on racing it then def get a mtb cassette. I have a road cassette on mine and im always hitting my chain on my chain stay. I have 3m tape there now but it still is anoying. I love the bike thought and never have had any problems with the guide.

  13. #13
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    BB shell is 100mm and chainline is I believe somewhere around 66mm.

    @nmpearson... that's what I thought you meant. Oh well, guess I'll just get a 36t front and a 12-34 cassette as suggested.

    @LucasP... thanks for the pic, helps me out a ton. You said you had a road cassette on yours, and I see you have a short cage RD. RD is bent beyond repair on mine--skips BADLY when torque is applied-- and was wondering if I could go with a short cage W/ a 12-34 cassette, or would medium be optimal?

  14. #14
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    Quote Originally Posted by the_Alaskan
    BB shell is 100mm and chainline is I believe somewhere around 66mm.

    @nmpearson... that's what I thought you meant. Oh well, guess I'll just get a 36t front and a 12-34 cassette as suggested.

    @LucasP... thanks for the pic, helps me out a ton. You said you had a road cassette on yours, and I see you have a short cage RD. RD is bent beyond repair on mine--skips BADLY when torque is applied-- and was wondering if I could go with a short cage W/ a 12-34 cassette, or would medium be optimal?
    I have run both my ancient short cage that is pictured, and a long cage xt. I didnt notice a difference. My bike shifted better with the long cage. Im pretty sure that is because my old short cage has so much play. For what it is worth my gearing in 11 13 14 15 16 18 19 21.

  15. #15
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    I have an '05 DH Comp with a 38t front ring and 12-34 cassette and an X9 "super-short" cage derailleur. It works great, the shifting is very crisp. Go for the short cage over the medium cage for sure- the shifting will be better and it keeps the derailleur a little bit more out of harm's way.

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