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  1. #1
    Beach-Bound Collin2424's Avatar
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    Chain slap...weak derailleur spring? Need some help please.

    Good morning!

    I've been happily riding my recently overhauled Peloton (here: http://www.bikeforums.net/showthread...fore-amp-After), but it has an issue that's driving me mad. I can't seem to take the slop out of the chain and it's constantly smacking the chainstay when I stop pedaling. I've read all over on how to get the chain length correct. I've got it just barely long enough to go into the large/large combination, and that's not a smooth shift at all. It really should have one more link in it to prevent damage to the rear derailleur.

    So what's left to do? I could shorten the chain, but then I won't be able to use all my gears. The front is a 53/42 and the rear is a 13-21. Rear derailleur is a Superbe Pro and the spring seems to be plenty tight. What else could it be? The freewheel was NOS and spins very freely. I'm out of ideas and since this doesn't happen on any of my other similarly equipped road bikes, I refuse to just "deal with it."

    Any insight from anyone? By the way, this obviously happens most notably on the 42T ring up front and basically any gear on the back. Thanks a ton in advance for any insight.

    Cheers,

    -Collin-

  2. #2
    十人十色 Dawes-man's Avatar
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    You didn't by any chance have the chain threaded through the RD when you checked the length, did you? I did that once and the chain did what you describe.
    "I bet you'd do the same if they was you." F. Zappa

  3. #3
    Senior Member zandoval's Avatar
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    Could you show pics with the chain over the largest and smallest rear gear...

  4. #4
    Senior Member toytech's Avatar
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    I had the same issue on a Trek 720 with Huret rd, an ultrasonic cleaning and a drop or two of motor oil on the pivots, pulleys and mounting bolt took care of it. The springs were fine but gummed up from sitting.
    "Never kick a fresh turd on a hot day."--Harry S. Truman

  5. #5
    Beach-Bound Collin2424's Avatar
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    Quote Originally Posted by Dawes-man View Post
    You didn't by any chance have the chain threaded through the RD when you checked the length, did you? I did that once and the chain did what you describe.
    What do you mean? So the chain may actually be too long? I don't see how that can be when it barely shifts into the largest cog on the rear and stretches the RD all the way.

    Quote Originally Posted by zandoval View Post
    Could you show pics with the chain over the largest and smallest rear gear...
    Will-do as soon as I get home.

    Quote Originally Posted by toytech View Post
    I had the same issue on a Trek 720 with Huret rd, an ultrasonic cleaning and a drop or two of motor oil on the pivots, pulleys and mounting bolt took care of it. The springs were fine but gummed up from sitting.
    Hmm, I don't have an ultrasonic cleanser, but maybe a thorough degreasing and oiling of the pivot points will help. Thanks!

    -Collin-

  6. #6
    Senior Member Chombi's Avatar
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    I'm wondering if you might be also getting some major drag from the freewheel (from old stiff grease and crud) as you noted you only get the slapping when you stop pedaling??. Clean and relube it too with your RD pivots just to make sure.
    Dipping the parts in mineral spirits works very well to melt the old grease from these components if you do not have an ultrasonic cleaner. Hit them with a good stiff plastic bristled brush to knock off all the crud from them.

    Chombi

  7. #7
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    Quote Originally Posted by Chombi View Post
    I'm wondering if you might be also getting some major drag from the freewheel (from old stiff grease and crud) as you noted you only get the slapping when you stop pedaling??. Clean and relube it too with your RD pivots just to make sure.
    Dipping the parts in mineral spirits works very well to melt the old grease from these components if you do not have an ultrasonic cleaner. Hit them with a good stiff plastic bristled brush to knock off all the crud from them.

    Chombi

    +1, the freewheel is continuing to turn after the crank stops revolving. The freewheel is DIRTY, very dirty. I'd say, take it off the wheel, soak it in solvent then spray into it with brake cleaner, let the solvents evaporate and give it a glorious bath of light weight oil.

  8. #8
    Beach-Bound Collin2424's Avatar
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    Okay, you guys have given me some hope! The derailleur is perfectly clean, but should I soak that as well?

    -Collin-

  9. #9
    Rustbelt Rider mkeller234's Avatar
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    I agree that the freewheel is your first suspect, Mike Mill's advice sounds good. When it comes time to re-oil the freewheel don't submerge it, spin the mechanism in one hand and feed it small amounts of oil... you should feel and hear the difference as the oil gets where it needs to.

    I also personally would not submerge a derailleur, or really anything, in oil. Just get a small bottle of triflow with a straw and lube each pivot point.
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  10. #10
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    Ah, I use the word "bath" in the poetic sense.

    It is important to give everything a fresh coat of oil because the solvents will strip every last bit of oil off of everything - even the cogs. Without a good coat of oil, things will quickly begin to rust. You can spray it on (pump or aerosol). You can wipe it on (oil soaked rag). Whatever you do, be sure to get everything, even the freewheel body.

    Submerging the freewheel will likely put too much oil inside and make a mess when you ride. If you stand it up on edge with a slight tilt to one side, sitting in the sun to heat it up, the excess oil will run out. Still, ...

    I hope you get the point.



    One way to test for this problem in the first place is to spin the freewheel. After spinning it, it should run for five to ten seconds before stopping. If it doesn't, it's dirty inside. After cleaning it should be better.
    Last edited by Mike Mills; 06-20-11 at 05:48 PM.

  11. #11
    十人十色 Dawes-man's Avatar
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    Quote Originally Posted by Collin2424 View Post
    What do you mean? So the chain may actually be too long? I don't see how that can be when it barely shifts into the largest cog on the rear and stretches the RD all the way.

    Hmm, I don't have an ultrasonic cleanser, but maybe a thorough degreasing and oiling of the pivot points will help. Thanks!

    -Collin-
    If the RD cage is pulled as far forward as it'll go on the large/large combination then the chain isn't too long - so we can assume that when you checked your chain length large-to-large it WASN'T threaded through the RD, right? (BTW, although large/large, plus one link, is the way to get chain length, that combination shouldn't normally be used while riding, nor small/small, as either can put strain on the chain and cause premature wear to the F & R cages.)

    You said the freewheel was spinning 'very freely' so that leaves the RD itself. As previously suggested, it would be a good idea to strip it and clean all the pivots and pulleys and regrease them. Another pointer is, perhaps, your mention of the RD spring being 'plenty tight'. I'm not sure about the design of the Suoerbe Pro but with every TD I've stripped there is a spring that when unhooked allows the whole derailleur to move through all positions without resistance. Doing that would show you if anything was binding.

    'Good luck!
    "I bet you'd do the same if they was you." F. Zappa

  12. #12
    Beach-Bound Collin2424's Avatar
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    Thank you guys ever so much. I haven't had a chance to pull the freewheel yet, but I have the bike here at work with me because I rode it in today. I do, however, have a cell phone camera. So, what combination can I snap some photos of?

    I also wonder about the position of the rear derailleur and that pivot screw. I never knew where that should be tightened to. I'll snap a photo just to show the position. It's in the 42T ring up frong and 4th largest cog in back. This is just a "normal" cruising gear for me when commuting. I think it's about 42/18.

    -Collin-

  13. #13
    Beach-Bound Collin2424's Avatar
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    Said photo:


  14. #14
    Senior Member
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    Collin, From the photo It looks like the upper run of chain is sagging slightly. If you push the tension wheel rearward does the the chain straighten? This could still be a freewheel issue.

    Brad

  15. #15
    Beach-Bound Collin2424's Avatar
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    Quote Originally Posted by bradtx View Post
    Collin, From the photo It looks like the upper run of chain is sagging slightly. If you push the tension wheel rearward does the the chain straighten? This could still be a freewheel issue.

    Brad
    Yes, pushing the pulley on the RD takes the slack out. I guess this could be a combination of a somewhat-weak derailleur spring and the freewheel?

    -Collin-

  16. #16
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    Yup, I'd say your RD spring is a weakling.

    Neal

  17. #17
    Beach-Bound Collin2424's Avatar
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    Quote Originally Posted by nlerner View Post
    Yup, I'd say your RD spring is a weakling.

    Neal
    It would kill me to have to put a non-original derailleur on this bike! I'm hoping cleaning will soft this. If not, I might just ride it with the chain clunking along.

  18. #18
    Senior Member toytech's Avatar
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    My experience is gunk is usually the culprit
    "Never kick a fresh turd on a hot day."--Harry S. Truman

  19. #19
    Senior Member DiegoFrogs's Avatar
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    You can increase the spring tension. It's housed around the big hex bolt that's lower on the picture. There are a whole bunch of notches to put it in. That's the way it is on my much earlier Cyclone, anyhow.

  20. #20
    Senior Member DiegoFrogs's Avatar
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    FWIW, I've never really gotten into one of these little fellers until recently. I've always been able to just adjust and clean them. I'm in the process of replacing pulley wheels and have one completely torn apart right now. But I was able to figure out the spring tension issue.

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