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  1. #1
    Formerly Gordo Grande Rip Van Winkle's Avatar
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    need help diagnosing a rear derailleur problem

    I need some help diagnosing some derailleur problems if you can. Iím posting this in the mechanics area as well as classic and vintage.

    I recently changed out the rear derailleur on my 25 year old Cannondale racing frame. Iíve had a 13-24 Suntour New Winner Freewheel on there with a Suntour Suberbe derailleur since the bike was built. (The front has been a Sakae triple with a 34-42-52 since about 1990). I recently decided to throw a bigger freewheel on the back in a concession to age and weight, (59 and 230 respectively) Iím hoping to shed the extra pounds by next year, at which time Iíll go back to the old setup.

    I have a pretty good parts bin, and had no trouble locating a 13-32 New Winner Freewheel in good shape, along with a Cyclone MK-II long cage derailleur. I also managed to find a brand new, NOS Sedisport chain in the original packaging. I put the whole thing together, taking three links out of the chain to fit the new drivetrain. Everything sounds perfect, doesnít it?

    Unfortunately, my first test ride the other day was a dismal failure. The derailleur shifted like crap and was noisy as hell. I was really surprised at this, since Iíve done this kind of modification many times. The chain often overshot the sprocket I was looking for, (I remember this being a not unusual problem with New Winners, since the spacing is fairly narrow), and I even managed to throw the chain to the inside of the freewheel once or twice. (Yes, I do know about the adjusting screws)!

    I put the bike back on the workstand today, and took a good hard look at the new setup. I realized that the pulleys on the old Cyclone MK-II were fairly worn, and the brand new chain wasnít seating correctly. The jockey pulley seemed worse off then the tension pulley, and it appeared that the chain was coming off the jockey pulley and clattering like hell.

    Back to the parts bin, and there I find a mint condition Cyclone MK-II short cage derailleur with perfectly new pulleys. I remember taking this particular derailleur off my wifeís new Nishiki International in1983, when I changed out her freewheel for a bigger one. I took the pulleys off the short cage derailleur and swapped them for the worn out pulleys on the long cage derailleur. Now I have a good condition long cage Cyclone II derailleur, with brand new pulleys, a brand new Sedisport chain, and a good condition 13-32 New Winner freewheel.

    Back out for a test ride, and Iím still getting a lot of clattering. Back on the rack, and it seems that now itís the tension pulley thatís making a lot of noise .The chain and pulley are having trouble staying synchronized, and the chain is jumping off the pulley a little.

    I have two theories, but Iíd appreciate some expert help if I can get it. My first theory is that I need to take another link or two out of the chain. My second theory is that the derailleur long cage might be bent after two and a half decades in the parts bin.

    What do you guys think?

    Thanks, in advance, for your help
    Rip van Winkle slept for 20 years, and when he awoke, all the bikes had changed!

  2. #2
    Senior Member DannoXYZ's Avatar
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    Hmmm.... stiff links in the chain?

    I'm not sure what you mean by "The chain and pulley are having trouble staying synchronized, and the chain is jumping off the pulley a little. " Is it pulling off the inside or outside of the pulley? Does the pulleys spin freely by hand? Sounds like perhaps the derailleur hanger may be bent?

    Can you post a video of this misbehaving RD/chain?

  3. #3
    Formerly Gordo Grande Rip Van Winkle's Avatar
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    Quote Originally Posted by DannoXYZ View Post
    Hmmm.... stiff links in the chain?

    I'm not sure what you mean by "The chain and pulley are having trouble staying synchronized, and the chain is jumping off the pulley a little. " Is it pulling off the inside or outside of the pulley? Does the pulleys spin freely by hand? Sounds like perhaps the derailleur hanger may be bent?

    Can you post a video of this misbehaving RD/chain?
    The pulley does spin freely. When I crank the chain through the derailleur at a high rate of speed the chain seems to jump a little every third or fourth revolution, as if the chain had been stretched and worn out. This is perplexing since both the chain and pulleys are brand new, (NOS). It's possible that the chain is still a little stiff at the point where I took it apart and put it back together, although I do think I flexed them side to side a little when I put the chain on the bike.

    That's a good idea about the video. I'll try to shoot some tomorrow.

    I'm thinking the hanger might be bent as well.
    Rip van Winkle slept for 20 years, and when he awoke, all the bikes had changed!

  4. #4
    Formerly Gordo Grande Rip Van Winkle's Avatar
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    UPDATE! I've been working on it, and it seems that the two pulleys are out of alignment. I bent the RD a little, and it seems to help the problem. It must have gotten bent slightlyl during its two decades sitting in the parts bin.
    Rip van Winkle slept for 20 years, and when he awoke, all the bikes had changed!

  5. #5
    Formerly Gordo Grande Rip Van Winkle's Avatar
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    UPDATE: It was definitely a bent RD cage, which I think I actually made worse in an effort to fix it. I took it into the LBS for an expert opinion. Easiest fix was replacing it with a new Deore RD. It shifts great now. Thanks all for your input.
    Rip van Winkle slept for 20 years, and when he awoke, all the bikes had changed!

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