New Chain Splitting

ptlk66
ptlk66 Posts: 52
edited September 2012 in Workshop
I have just fitted a new Campagnolo 10 Speed chain connected with KMC 10 Speed Campagnolo missing link. This is the first time I had to measure a new chain for fitting so I used the method of chain over large chaninring and large sprocket (not through rear derailleur) to the nearest joining point (allowing for missing link) plus two additional links.

Today was my first trip with the chain and while the chain moved nicely up and down the cassette I could detect a rubbing sound from the chain while in the large chainring only. After seven miles the chain split at the missing link. I refitted the chain with a new link and completed the remaining 10 miles to work. I am a little concerned as I have 110 mile bike run coming up on Sunday and wouldn't like to see this recur again.

Q: Is this a sh!t happens moment and the link was probably defective or have I done something mechanically incorrect? Should I get the system checked over by a bike mechanic??

thanks

Comments

  • keef66
    keef66 Posts: 13,123
    I've never had a missing link fail.

    Did it snap into place when you pulled the adjacent links apart when installing it? Did you check to see that the sideplates had properly engaged the grooves in the pins on both sides?

    Or are you saying that the link actually broke?
  • estampida
    estampida Posts: 1,008
    I thought it went through the rear mech as well

    pull it tight and give it 1-2 extra links......

    if that is wrong 22 years of indexed gears without fault...
  • father_jack
    father_jack Posts: 3,509
    If you're unsure, you can just count the number from your old chain, as long as bike shop did it right. But I guess it's a good idea to learn how to measure chain.
    Say... That's a nice bike..
    Trax T700 with Lew Racing Pro VT-1 ;-)
  • buckmulligan
    buckmulligan Posts: 1,031
    estampida wrote:
    I thought it went through the rear mech as well

    pull it tight and give it 1-2 extra links......

    if that is wrong 22 years of indexed gears without fault...

    Nah the OP has got it right, around the biggest chainring and biggest sprocket WITHOUT going through the derailleur and then add 2 links. I've heard a rule of adding 3 links for MTBs, perhaps because they typically run triple chainsets and thus longer cage derailleurs. If you're running a triple on your road bike, maybe add 3 links instead? This is pure speculation though! I can't be @rsed to look it up, but Sheldon Brown will have all the answers you need.
  • cycleclinic
    cycleclinic Posts: 6,865
    3 links is usefull on bike with those 15T jockey wheels. A tripple chainset make no difference in sizing the chain. Add three link to normal sized jockey wheels and the chain will be too long for small small which you should not be in anay way.

    I suspect the link was joined securely and one plate was not fully engaged on the pin. It will run fine like that for a short while and then the link will seperate.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • ptlk66
    ptlk66 Posts: 52
    Thanks for all the replies - No issues on journey home or into work again today - circa 45 miles with new pin. I will go with the theory that I hadn't fully engaged the link.

    As an aside, I put the bike on the bike stand when i got home, counted the links, and the new chain has two additional links (using the method i stated earlier) to the old chain which was fitted by the bike shop. I noticed when in small/small the chain is rubbing the rear derailluer guide - although I should never be in this gear, I may remove two links to add a bit more tension.

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