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  1. #1
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    Chain rubs on itself (rear derailleur)

    When I shift into the small/small combo the rear derailleur folds back and the chain rubs against itself. This is a completely stock specialized hardtail so I am assuming they used the proper cage SRAM derailleur (it appears to be mid or short cage). When I shift to big/big there is no extra chain so it seems as if the rear derailluer is the wrong size.

    Can anyone weigh in on this? Is there some setting (B-stop maybe) that will bring the rear tension pulley down enough so that the chain wont rub at the guide pulley?

  2. #2
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    Small/Small is cross chaining...no reason to ever need to ride in that combination.

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    I am aware but still it shouldn't do this right?

  4. #4
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    Quote Originally Posted by Brian06 View Post
    I am aware but still it shouldn't do this right?
    Chain length is sized according to several factors including the largest chainring and largest rear cog. To prevent damage, a chain is at least sized so if you go into your big ring/big cog (again cross chaining, shouldn't ever be done) that it will not tear off the rear derailleur. Also some full suspension models exhibit chain growth so an extra link or two may be necessary to prevent damage. The rear derailleur cage may factor into the equation as well.

    In the end, if your bike is shifting correctly I wouldn't worry about it...don't ride small/small

  5. #5
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    Adjust the derailleur angle, there should be a screw for this near the hanger...

  6. #6
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    When I read the title of the thread, my first thought is that it was going to be a specialized bike..................
    I'm not sure why Specialized specs the medium cage derailleurs on their bikes.
    Every one of their modern bikes that I have worked on has them, and it is impossible to get the proper chain length on a triple chainring setup using a medium cage derailleur. Especially tough when it is on a full suspension bike.
    The chain will always rub over itself when in the small/small combo.
    For most people it is not a big deal since you should never really run that gear combo anyways, but some people do so without knowing any better.
    I understand that the shifting will be a little faster/crisper with the medium cage der and it offers better clearance, but I've never understood why they insist on spec'ing the medium cage on their bikes.
    It kind of opens them up to some issues. Possibly ripping derailleurs off bikes, and potentially getting somebody hurt.
    Not to rant on Spec, I think they make some great bikes. But this baffles me.
    Look, whatever happens, don't fight the mountain.

  7. #7
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    Quote Originally Posted by -Todd- View Post
    Adjust the derailleur angle, there should be a screw for this near the hanger...
    You don't want to tinker with the B-Tension screw if it is set properly. Thats not what it is there for. It is there to set the clearance between the der pulley and cassette cog.
    The proper spacing is pretty important.
    Look, whatever happens, don't fight the mountain.

  8. #8
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    take a few links out of the chain

  9. #9
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    Quote Originally Posted by Brian06 View Post
    I am aware but still it shouldn't do this right?

    True on a normal 22 32 44 11-34 set-up a long cage RD will not result in chain rub...

    However since the little little combo is pretty damn useless...to get better performance..some think using a medium cage is better....


    I regularly use big/big combo..bombing down a gully at high speed then trying to get out over the top...no time for a FD shift...

    The only time I have used little little is when I have forgotten where I am in the gears...

    My shifters donot have indicators.

  10. #10
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    Quote Originally Posted by Customization View Post
    take a few links out of the chain
    It's not that easy. OP stated when in the big/big combo the chain is already tight.
    Removing a few links will cause the derailleur to rip off the bike if shifted into the big/big.
    The only solutions are to either be very careful which gears you select ( easier said than done) or buy a new long cage der and possibly a new chain.
    Look, whatever happens, don't fight the mountain.

  11. #11
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    Quote Originally Posted by mtnbiker72 View Post
    To prevent damage, a chain is at least sized so if you go into your big ring/big cog (again cross chaining, shouldn't ever be done) that it will not tear off the rear derailleur.
    In the end, if your bike is shifting correctly I wouldn't worry about it...don't ride small/small
    So there are lots of uses for the big big combo so go ahead and cross chain if the situation warrants...

    Go little little if you want...(can't think of why you would want).

    You will wear things out a little bit faster if you do cross chain.

    In the end though your bike is working ride it.

  12. #12
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    Quote Originally Posted by savagemann View Post
    When I read the title of the thread, my first thought is that it was going to be a specialized bike..................
    I'm not sure why Specialized specs the medium cage derailleurs on their bikes.
    Every one of their modern bikes that I have worked on has them, and it is impossible to get the proper chain length on a triple chainring setup using a medium cage derailleur. Especially tough when it is on a full suspension bike.
    The chain will always rub over itself when in the small/small combo.
    For most people it is not a big deal since you should never really run that gear combo anyways, but some people do so without knowing any better.
    I understand that the shifting will be a little faster/crisper with the medium cage der and it offers better clearance, but I've never understood why they insist on spec'ing the medium cage on their bikes.
    It kind of opens them up to some issues. Possibly ripping derailleurs off bikes, and potentially getting somebody hurt.
    Not to rant on Spec, I think they make some great bikes. But this baffles me.
    Question for you savageman... I am swapping my long cage tripple setup on my Enduro SL (2007) to a medium cage to get crisper shifting.

    I've been riding for many years and I never use small/small or big/big - not even accidentally.

    Question is, does specialized run this mid-cage setup a link short from a long-cage setup? Or the same chain length and put up with some chain rub in the small/small combo?

    In actuality, with the rear suspension uncompressed the chain appears to be a link long coming from factory setup (big-big bypassing derailleur). But when I let the air out of the shock and conpress it fully, the chain length grows by a link and looks just right.

    So If I run a link shorter, I'd have to be in the big/big combo and fully compress the suspension to run into a problem.

    Thanks!

  13. #13
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    Megabump of old thread...

    Yeah I thought my Fuel EX 8 really protested small/small cross-chaining, until I picked up this '01 or '02 KHS full squishy off craigslist as a guest bike. It didn't shift great (med/small) then this guy endoed it in front of the office and tweaked the hanger. My guess is it was already tweaked. Replaced it. It shifts okay now and I was trying to figure out though what the hell happened. Why does chain rub itself on small/small? Did it always do this? Did the last owner put on too many chain links? (nope)

    Now I look, and yes, it's definitely medium. The Fuel EX thankfully has a long. And honestly if something looks like it's going to end up in the spokes it's the Deore LX on the KHS, not the XT on the Trek.

    Thank you guys for solving this mystery year(s) before it cropped up. It's really annoying though, because if you accidentally put it in this, the chain goes slackish. After a bumpy downhill it'll end up on a random sprocket and/or off the ring entirely. Novice guest rider will likely do this too. Ugh.

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