Chain skipping (new chain and cassette)

Discussion in 'Road Cycling' started by srixon, Apr 14, 2012.

  1. srixon

    srixon New Member

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    Hi, I'm hoping for some help in diagnosing a problem I'm having with the chain skipping. I just got my bike (Specialized Roubaix) back from the bike shop after having the chain and cassette replaced and went out for a ride. I noticed pretty quickly that the chain seemed to be skipping often if I hit a bump while pedaling or whenever I started from a stop and pedaled hard.

    Anyone know what may be causing this? I'm fairly new to the cycling world and I'm doing my best to figure out how everything works, but I've got a lot to learn still!
     
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  2. alienator

    alienator Well-Known Member

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    It's most likely happening because your rear derailleur cable tension is a bit off. You can either take it back and tell the LBS the RD needs adjusted because the chain is skipping, or you can read up on the procedure at Park Tools website. The section you likely need to read is the one near the bottom of the page about Indexing Adjustment.
     
  3. srixon

    srixon New Member

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    Thanks for the input, When researching the problem earlier I had read some things that made me think that it could be something to do with the indexing. I didn't notice any issues with shifting while I was on my ride - is it possible for the gears to shift fine if the indexing needs to be adjusted?
     
  4. alienator

    alienator Well-Known Member

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    Yes, absolutely. What happens when you "adjust the indexing" is that you adjust the rear derailleur cable tension, which ultimately aligns the rear derailleur's top pulley with respect to a given cassette cog. If that cable tension is too loose, the chain may have difficulty shifting to the next bigger cassette cog or may shift to the next bigger cog but then skip back to the lower cog under power. If the cable tension is too high, the RD will shift to bigger cogs quickly but will shift to smaller cogs slower than what is ideal. The RD may even skip a cog and go to an even bigger cog if the tension is too high. Sometimes when the adjustment is out of whack and the tension is high enough, you may only get access to 9 out of 10 cogs....or 8 out of 9, depending on the system you have. In both cases--cable tension too high and cable tension too low--you'll most likely hear excessive chain noise while pedaling. No matter the case, the tutorial for making that adjustment on the Park Tool site is about the best available and is also a solid technique. Quasi related.........you should bookmark the Park Tool site since the site gives tutorials for virtually any adjustment, maintenance, or installation you might do to the bike. All of their tutorials are straight forward and easy to understand. It's a great resource. Believe it or not, another great resource for learning about bike maintenance and repair is YouTube. There are video tutorials for virtually anything you might want to do to your bike. Lastly, you should also bookmark the website for whatever company makes your component group: Shimano, Campagnolo, SRAM, or Microshift. They all will have (at least Campy and Shimano do) all the relevant installation and maintenance instructions (in pdf format) on their website. I keep pdf's for virtually all my bike components on my computer, just in case I incur a head injury and can't remember how to do something or if I need to do something I haven't before. A couple big bonuses to learning how to work on your bike are that it is of course cheaper than having an LBS do it (shop time in an LBS can be on the order of $50/hr--give or take a couple or more dollars); it can be immensely satisfying; and it makes you more aware of your bike's condition.
     
  5. srixon

    srixon New Member

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    Thanks for the info alientor. I am definitely trying to learn how to do as much of the maintenance as possible but there are a lot of details to learn - the Park Tools site certainly looks helpful. I spent some time this morning adjusting the indexing but still seem to be having the problem. I am wondering now if the middle chain ring is worn because this is where I spend the most time riding and I don't seem to have the skipping problem when I am on the highest and lowest chainrings. I may bring it to the LBS today since they should at least take a look at it and diagnose the problem because it may be that something wasn't properly adjusted after the cassette was replaced.
     
  6. srixon

    srixon New Member

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    UPDATE - After tinkering around on my own to no avail, I brought the bike over to the LBS for them to have a look. The mechanic was more than happy to put it up on the stand and have a look since it was there for some work last week and pretty soon after he noticed that the pin on chain was too long and was sticking out and hitting the cassette. I think the odds of anyone else having the same problem are pretty slim, but maybe this post will help someone in the future
     
  7. oldbobcat

    oldbobcat Well-Known Member

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    The odds of anyone solving the problem without seeing the bike would be pretty slim, too.
     
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