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chain stretched...............

Discussion in 'Bicycle Mechanics and Repairs' started by Panter, 10 Feb 2008.

  1. Panter

    Panter Just call me Chris...

    Ok, so now my chain wear indicator falls into the gaps so I need a new chain.

    Now the confusion. I go to the CRC website and there are hundreds of chains listed :angry:
    The original is a KMCZ72 but as it hasn't lasted 700 miles I'm keen to get something a bit tougher. Any recommendations for what to get?
    Its a SRAM cassette but Shimano derailleurs, 8 speed.

    I also need a chain splitter, can someone recommend a decent one that is easy to use but also one I can carry with me (doesn't need to be light)
    Do I also need these pins to rejoin a chain? would I need these to effect a temporary repair if a chain breaks on the road?

    Any help appreciated (sorry I've never done a chain before ;) )
     
  2. fossyant

    fossyant Ride It Like You Stole It!

    Location:
    South Manchester
    I'm using KMC X8 99 range on my commuter and training bike and they have been fine and come with a 'power link' so no chain tool needed.

    As for the joining pins - you'll get one with a new shimano chain, but if you take it off, you'll need another pin to rejoin it.

    Rivet extractors - park are pretty good.

    A nine speed chain will work on 8 speed systems fine.
     
  3. OP
    OP
    Panter

    Panter Just call me Chris...

    Thats great, thanks for the help :biggrin:

    So, if I buy this as a replacement then, I wouldn't need a splitter assuming I could cut the old chain off?

    If the above chain were to break on the road, would I be able to repair it by just carrying one of these or would I still need a splitter to remove the broken link?

    Sorry for the dumb questions, I'm also trying to kill 2 birds with one stone as I want to be able to repair a broken chain whilst out and about including that on the MTB.
     
  4. andrew_s

    andrew_s Veteran

    Location:
    Gloucester
    This
    Park chain tool
    is what I use at home or when touring. For day rides I use the one on my Topeak Alien.
    5/6/7-speed chains can be rejoined by using the chain tool to push the rivet back in (provided you didn't push it completely out). The rivets on 8/9/10 chains don't protrude far enough past the outer sideplate to allow a reliable connection, so you need either a special pin (Shimano) or a joining link (everyone else). The Shimano pins aren't too good out on the road as you need a pair of pliers to snap off the end section, so most Shimano chain users take a SRAM or KMC joining link (if they take anything).

    If a chain breaks out on the road, you will want the chain tool to remove the mangled chain link, so both ends finish in inner links. You can then use a joining link to connect them. Don't forget to check it's correctly through the rear mech first:smile:
    The chain tool is also required when fitting a new chain as you'll probably want to trim a few links off so it's the right length for your bike.

    If you want to split a chain at a joining link (eg for cleaning), it's best to practice on a new chain. There's a bit of a knack to the necessary squeeze and slide movement, and it's easier when everything is clean.

    Chain recommendations are difficult because chain wear varies so much, depending on riding conditions like rain & mud, cleaning regime, lubricants etc. SRAM have said that all their chains go through the same hardening process and so they should wear at the same rate. Other manufacturers are probably similar.

    Note that the wear limit that your chain checker is giving is the point at which a new chain will likely give problems on your old cassette. If you go beyond this point, you will have to change the cassette as well or you will get chain slip. However, if you just carry on using the chain, it should last for more like 5000 miles until it starts to give problems. You could take the view (like me) that it's cheaper to buy a new chain and cassette every 5000 miles than a new chain every 7-800 miles.
    (It's more complicated than the above simple cost comparison, as there's chainring wear to factor in, and cassettes don't last indefinitely if you do change chains often)
     
  5. OP
    OP
    Panter

    Panter Just call me Chris...

    Thanks for the informative post, very much appreciated :biggrin:


    That sounds like very good sense to me. I think though, on this occasion, I will replace the chain. Primarily because i've never done one before so I want to at least get some experience of it. Secondly, I take very good care of my chain and I'm quite surprised its worn so quickly. I was kind of hoping to get double that mileage out of it as I clean and re-lube after every couple of rides, mebbe a better spec'd chain will gve more mileage?

    When the next one wears though, I may well leave it to wear with the cassette and then just change both :biggrin:

    I'll order those bits then and crack on it with it as soon as they arrive :smile:
     
  6. squeaker

    squeaker Über Member

    Location:
    Steyning
    Wear rate

    That may be where you are going wrong, depending upon how you 'clean' it. Personally, on a road bike chain (MTB's covered in cack do need washing first) I just wipe the chain with a rag, then apply a decent chain lube at the pins, followed by another wipe over after a few spins of the cranks.
    As you will soon find out, others may have different opinions :angry:
    (And you will need a chain splitter tool to get your new chain to the right length - same # of links - as the old one.)
     
  7. OP
    OP
    Panter

    Panter Just call me Chris...

    Thanks Squeaker, thats what I do actually, I believe its called the "Mickle method" :angry: :biggrin: hence my surprise at the short lifespan.


    I've just ordered all the new bits so hopefully I can have a go at fitting it tomorrow :ohmy:
    I'll probably have a good practice at splitting the links on the old chain frst.
     
  8. Jacomus-rides-Gen

    Jacomus-rides-Gen New Member

    Location:
    Guildford / London
    Chains are strange creatures, I have full Shimano Tiagra on my roadbike, but Shimano chains seems to be made from cheese. I've never tried a KMC chain, though they have a good reputation. For me the numero uno has to be the SRAM PC-991.

    Sheldonbrown.com has a very good section on how to size your new chain.

    Andrew s - you must be barking!! How can replacing a cassette and a chain be cheaper than just a chain?!?!? Your cassette won't experience any trouble for thousands of miles if you use your gears properly, and change your chain on the 0.75% wear indicator falls through.

    Remember to check your chain on the top run, when it is taut, so put some pressure through the pedals then measure. Personally I meansure the chain in three different places, by turning the cranks a little after each measurement, and when the tool slips though on 2 points at the 0.75% level I put on a new chain.
     
  9. andrew_s

    andrew_s Veteran

    Location:
    Gloucester
    A SRAM 991 chain is £20
    An Ultegra 12-27 9sp cassette is £25
    (Chainreaction prices)

    If I ride 5000 miles, I've spent £45 (I usually get more than 5000).
    If you ride 5000 miles and change your chain every 1000 miles, you've spent £100 just on chains.
     
  10. OP
    OP
    Panter

    Panter Just call me Chris...

    That does seem to make very good sense. Even if you factor in a cheap chain (like the one I ordered at £10something, it still works out to a fiver more over 5000 miles. Plus of course the hassle of keep changing chains.

    I had no idea that cassettes were that cheap either, I think my obsessive cassette cleaning is probably a false economy in the long run with that in mind.

    EDIT: Actually, I've just checked CRC. My bike has a SRAM PG850 cassette which is £14.99. Thats only a fiver more than the chain ;)
    That was the last clean my cassettes ever going to see :laugh: :biggrin:
     
  11. Jacomus-rides-Gen

    Jacomus-rides-Gen New Member

    Location:
    Guildford / London
    But why on earth would you want your shifting performance and reliability to decrease like that??

    I am also sceptical that you can extend a chains service life by 5 times simply by running it into the ground.

    To me a bicycle is a piece of precision machinery, and I maintain it as such. For instance, I can't stand gears not working properly and have a little fettle of the bike every time I clean it (which is often!!). I won't let my brake adjustment change, so I make sure to keep adjusting when it is needed.

    I guess you must see your bike differently to me, in which case your system works for you. As long as it makes you happy (and I never end up riding your bike ;) ) its all good!
     
  12. ransos

    ransos Usual suspect

    Well, you learn something everyday! I always assumed the powerlink on SRAM chains was just for convenience, not because it's the only reliable way of joining the chain.
     
  13. Graham O

    Graham O New Member

    Since all the chain experts are gathered together on this thread, I think I'll show my ignorance and.........

    Last night riding home on a lovely evening on country lanes, my 8 speed chain decided to break. To repair it, (and those that have broken in the past) I just used a chain tool to get back to the next link with plates, pushed out the rivet, fitted the two ends together and re-rivetted it. Is this the correct way? Or should I have had a joining link in my tool box and used that to join it? Certainly the link would be quicker, but if they require tools, then I'd need to carry more with me.

    PS What was really annoying was that the first 3 links couldn't be separated with the chain tool so I ended up losing 3 links and now the chain is too short :wacko: So based on the advice from here, I'll get a new one with the right bits!
     
  14. Tynan

    Tynan Veteran

    Location:
    e4
    some interesting facts there on the OCD drive train maintenance debate

    so let it run with minimal cleaning until it fails then yeah?
     
  15. andrew_s

    andrew_s Veteran

    Location:
    Gloucester
    5/6/7 are indeed just push out the rivet then push it back in as you said.
    For 8/9/10 you should carry a joining link or two in your toolkit. They don't need any tools, but you'll probably need a chain tool to remove the broken outer link so you have 2 inner links to join with the link.

    8-speed may just about be re-riveted if you are careful, but last time I tried with a 9-speed it lasted a whole 1/4 mile before it broke again.
    It's not just the amount of projection, but that the ends of the rivets are bashed during manufacture (peened) so that they bulge a little and grip the inside of the hole in the side plate. Pushing the bulge right through expands the hole a little, so the pin doesn't grip when you push it back.