has my rear cassette gone?

redvision
redvision Posts: 2,958
edited March 2011 in Road beginners
hiya

so i put a new chain on the winter bike last week and immediately had issues with 4th and 5th gear (in both lower and upper chainring). all other gears are fine. these two seem to skip, but not like its trying to move in to another gear, and they only do it under power/pressure - when riding smoothly they seem ok.

could it be a simple case of adjusting the rear derailleur screws? or given that the old chain was pretty worn and the cassette is only sora, could it be that the worn chain has worn the cassette?

would really appreciate any help and advice

thanks

Comments

  • neeb
    neeb Posts: 4,467
    Sounds like the cassette is worn (or at least some of the sprockets). If you change it asap you might save the new chain from becoming worn very quickly.

    Have you changed the chain before on this cassette, and if not, do you know how worn the last chain was? If you want to use several chains on the same cassette you need to change them before they are about 0.75% worn.
  • green_hornet
    green_hornet Posts: 20
    The same thing just happened to me this week. I put a new chain on and thought the freehub was slipping as that was new too. The bloke in the LBS was sure it was a worn cassette so I invested in a new one. He was right.

    Seems that your old chain will work well with a worn cassette as they remain matched as they wear together.

    I'm starting to get chain suck now :(
  • Berk Bonebonce
    Berk Bonebonce Posts: 1,245
    A chain wear guide is money well spent. They tell you when to buy a new chain. Don't replace the chain when it should be replaced and it can result in wear on the cassette sprockets, which I think you are now seeing.

    Perservere with it a bit. Make sure you have set up the rear mech correctly so that you can rule that out. After a bit of perserverence you might find that the new chain beds in somewhat and starts to work smoother. If problems continue and you mash your nuts up on the crossbar after having the chain slip (assuming you are male), well, that is the time to buy a new cassette.
  • furrag
    furrag Posts: 481
    Have you set the B-adjustment screw, making sure the derailleur is close to the cassette?
  • redvision
    redvision Posts: 2,958
    chain was very worn tbh, even though it had only done about 1000miles!
    guess it might be worth changing cassette and seeing if that helps.

    thanks for the advice fellas
  • John.T
    John.T Posts: 3,698
    Furrag wrote:
    Have you set the B-adjustment screw, making sure the derailleur is close to the cassette?
    Believe it or not that actually makes things worse as the chain has more teeth to climb up.
    Redvision. You have 2 options.
    1/ Carry on and see if it beds in. It may well do. I had this problem when I fitted a new chain just before a long day in Kielder (MTB). Two gears jumped quite badly but by the end of the day all was fine. I did get a new cassette with the next chain.
    2/ Get a new cassette asap and save the chain.
    No 2 is the safest but it is up to you.
    If you have only done 1000 miles on the chain you need to check your maintenance schedule. Unless you use it in very bad conditions you should get more than that. I reckon on nearer 2000 for a chain in winter with 2 chains for each cassette. In summer they seem to last for ever.
    My Fleet.
  • redvision
    redvision Posts: 2,958
    John.T wrote:
    Furrag wrote:
    Have you set the B-adjustment screw, making sure the derailleur is close to the cassette?
    Believe it or not that actually makes things worse as the chain has more teeth to climb up.
    Redvision. You have 2 options.
    1/ Carry on and see if it beds in. It may well do. I had this problem when I fitted a new chain just before a long day in Kielder (MTB). Two gears jumped quite badly but by the end of the day all was fine. I did get a new cassette with the next chain.
    2/ Get a new cassette asap and save the chain.
    No 2 is the safest but it is up to you.
    If you have only done 1000 miles on the chain you need to check your maintenance schedule. Unless you use it in very bad conditions you should get more than that. I reckon on nearer 2000 for a chain in winter with 2 chains for each cassette. In summer they seem to last for ever.

    thanks for your advice. i have ordered a new cassette so hopefully that will sort it. in meantime how much damage will it be doing to the chain if i use it? im hoping the cassette will be here by weekend, so will it be ok to use in the meantime? its 4th and 5th gear which the skip happens, so i guess i could try to avoid using these gears??
  • John.T
    John.T Posts: 3,698
    You should be OK for a short while. Try to avoid using those sprockets. You can probably find similar ratios on the other ring even if it means cross chaining a little.
    My Fleet.

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