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Pls help: Chain Skip(8 posts)

Pls help: Chain SkipMaverick
Jan 25, 2003 11:20 PM
Guys,

My bike shifts perfectly smooth at all gears. however eversince changing to a new wheelset, i have been experiencing an intermittent problem whereby under hard pedalling the chain would skip. like i said, the problem occurs irregularly and i'm quite sure it probably has nothing to do with the rear derailleur setup since shifting is buttery smooth.

i would say most of the cases occur while standing up accelerating. i'm sure the problem is related to the drivetrain.
Current setup is on D/ace cassette and r/derailleur, with Ultegra chainring. Total mileage on the cassette and derailleur is around 5000 miles, chainring and chain around 3000 miles.

could it be due to chain wear, or even cassette wear? btw the rear derailleur looks fine to me.
is there any way we could examine if the cassette or chain is already worn out?

my LBS has no idea on solving the problem above.

Thanks for the help
possibilities...C-40
Jan 26, 2003 5:52 AM
You must have a lousy LBS if they can't solve a simple problem like this.

If the derailleur cable is adjusted properly, shifting is accurate and the skip that you describe is NOT a case of the chain trying to move up or down to the the next cog, then the problem is worn out parts. If what you describe is the chain moving up or down on the cassette, then it's a case of cable misadjustment or perhaps derailleur misalignment. Your LBS should have the tools to check derailleur alignment.

True chain skip usually occurs on only one or two of the the middle cogs that are the most heavily used. Chain skip usually occurs immediately after a new chain is installed on an old cassette. The new chain doesn't match the worn pattern of the old cassette, and skipping results.

Since you have 3000 miles on your chain, you probably need a new one. The standard method of measuring chain wear is to measure a 12 inch length. If the center to center distance between pins has increased to 12-1/16" or more, then a new chain is in order. Park tool also makes a chain wear measuring tool that is reasonably accurate. If you put a new chain on the old cassette it should skip even worse than before, if the cassette is worn.

If all you got was 5000 miles from your cassette, you should consider improving your maintenance technique and/or getting a cheaper Ultegra cassette with all steel cogs. Ti cogs won't last as long. You should get a lot more miles from a road cassette, unless you ride in dirty/wet conditions frequently.
re: Pls help: Chain Skipmackgoo
Jan 26, 2003 6:05 AM
Things were OK prior to switching wheel sets? If this is the case, did you transfer your old cassttes over? THis happened to me after putting on a new chain with old cogs after about 100 miles things beded in and worked fine. In your case if it's different cogs maybe this is the same phenomona, I would say after a few miles things will work. If everything is the same except the wheels, I wonder if the dish is a little different. Once also I had a problem like this although not as persistant, it turned ot to be wornt bearings.
re: Pls help: Chain SkipMaverick
Jan 26, 2003 7:35 AM
new wheelset with used cogset and chain.

i guess should be due to worn out cogs or chain.
have so far covered almost 200 miles on the wheelset, chain skip still occurs irregularly, and mostly happen on the 5th cogset (frequently used)
sounds like chain catching on next cogcyclopathic
Jan 26, 2003 10:30 AM
adjust RD. Some freehubs have a bit more wobble and it may be just enough. Screw in adjustment barrel on RD 'till it shifts slow then back it 1/2 turn. If it were a new chain I'd check for stiff link, worn cass, etc.

While at it check the chain stretch. Depend on lube, maintenance and riding conditions 3,000mi could be the end of chain life.
Key question: how worn is the chain?Kerry Irons
Jan 26, 2003 7:18 PM
The message is that you changed the original chain at 2K miles, but are now taking this one to 3K miles. How much elongation do you have? It's easily measured with a ruler - no need for fancy tools. If you have more than 1/16 elongation in 24 links (12 inches) then things are fading fast. More than 1/8" and time for new chain AND cassette. The confusing thing is that this started right after you moved the old cassette to the new wheels. You did get the cogs on right (facing the right direction), didn't you? If yes, then it may just be a coincidence that it started with the wheel change. THE common cause is a new chain on old cogs, or an old chain on new cogs.
Key question: how worn is the chain?Maverick
Jan 26, 2003 10:27 PM
old chain with old cogset

should i change both or only the chain??

i don't think it has anything to do with r/d adjustment since shifting is ultra smooth though skipping occurs but hardly. must be due to worn out drivetrain..

thanks for the help guys
chain first, then cogs...C-40
Jan 27, 2003 8:51 AM
True chain skip gets worse with a new chain. If you change the chain and the skipping continues, the cassette is worn and should be changed also.

If your problem persists with a new chain an cassette, it's not chain skip, its some type of derailleur misadjustment.