Chain break, why and how best to fix?

Discussion in 'Cycling Equipment' started by scarleton, Aug 24, 2013.

  1. scarleton

    scarleton New Member

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    Well, I am back on my bike this year after many years away. I have been LOVING it, until today:( I broke my chain about 12 miles into a 70 mile ride. I came looking for some tips on the subject and saw some other posts that where asking about why their chain broke and a common question was: What does the break look like? Here is a picture of mine:


    [​IMG]

    I was at the beginning of one of the steepest hills of the ride when it broke. I was very blessed to be in a BEAUTIFUL spot and have an amazing wife with a van that was able to pick me up.

    [​IMG]

    So I try very hard not to cross chain, but it does happen from time to time, but NOT when going up hills like this. One thing I have been noticing is that the chain had come off a few times in my last ride when I was shifting up. This started to happen AFTER I first noticed:

    1st: About a month ago (been riding since May) the chain would skip a bit on the back when on the highest rear gear but the middle crank gear.
    2nd: About a week ago, noticed the same thing when on the top gear at both ends.

    I also noticed some other things, while waiting for my wife, I noticed the crank has some play in it. It is really hard to get the crank on the granny wheel (smallest crank).

    So my thought is that the EXAGE 400 LX derailleur on my 23 year old Moody Fox is not staying set correctly, which is causing the derailing, which is causing chain failure.

    [​IMG]

    I also noticed a lot of what looks like new ware on the frame by the crank. Is this normal or a sign of something else?

    Sam
     
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  2. oldbobcat

    oldbobcat Well-Known Member

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    Age, chain wear, dirt, worn cogs, and badly functioning derailleurs are the usual causes of chain breakage. If your chain had more than 3000 miles on it, it was borrowed time anyway. If cassette or freewheel (whichever your bike uses) has more than 4000 miles on it using the same chain, it's on borrowed time, too. Be honest.

    The skipping sounds like a worn cassette/freewheel. Get a new one. The chipped paint on the chainstay is usually not caused by direct contact with the chainrings but by the chain getting caught in there. The middle chainring looks worn, which might be causing "chain suck." Chain suck happens when a chainring holds onto the chain instead of releasing it as it passes to the rear derailleur.

    Clean the drivetrain and make sure everything lines up. Get a new chain and cassette/freewheel. Consider replacing middle chainring. If you're not sure, take the bike to a shop and ask an experienced mechanic for a second opinion.
     
  3. alfeng

    alfeng Well-Known Member

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    Okay ... someone will probably need to get the smelling salts out for oldbobcat because [after THIS post (above)] I am going to suggest that you may actually want to consider a trip to your LBS for a new bike!?!

    THIS is a great time of year to check our your PERFORMANCE or TREK store for some deeply discounted prices on some models ... you have the advantage of needing a bike with an XL-or-L frame which will probably be available vs. a frame for us comparatively small riders who are under 6'0".

    FYI. The occasional cross-chaining is the reason that your chain finally broke BECAUSE a chain-with-bushings [as pictured] is laterally much stiffer than bushingless chains (it will be almost impossible to buy a 3/32" Road chain-with-bushings, now, BTW) ....

    • due to the lack of lateral flexibility, each time you cross-chained the chain-with-bushings you were applying side pressure on the plates ...
    • THAT initiated unintended splaying of the plates until at least one plate was no longer engaged & THAT undoubtedly resulted in the dodgy shifting ...
    • finally, when you were riding uphill the one-last-time there was enough force to tear the pin from OTHER plate

    ​If you have not already replaced the chain, then an 8-speed SHIMANO or SRAM chain will "fix" the specific problem + possibly the recent shifting problem.

    Regardless, I do not know how easy it will be for the average person to replace what appears to be a STEEL inner chainring of an unknown BCD from the spider to which is probably riveted from what appears to be a steel chainwheel and so at some point in time the crank & BB may actually need to be replaced.

    Let's see ...

    1. chain ... $20-to-$50
    2. chain tool ... $8-to-$150
    3. new wheelset (vs. re-lacing the rim on an Acera/whatever hub)... $100-to-$1000
    4. 11-32 Cassette ... $25-to-$150
    5. new crankset ... $50-$500
    6. BB tools ... <$50
    7. Deore shifters ... <$50
    8. 9-speed front derailleur if a Triple crankset & chain & Cassette are installed

    Oh, wait!!

    If you can do any DIY work on your bike then $300 is still probably less than the cost of a new bike discounted during an end of the year sale ...

    On second thought, "hold" the smelling salts ...
     
  4. CAMPYBOB

    CAMPYBOB Well-Known Member

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    Lubrication...there is no sign of it.
     
  5. oldbobcat

    oldbobcat Well-Known Member

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    Thanks for thinking of me, alf, but I'm OK.

    Yeah, this might be a good time for a new bike.
     
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