I have cleaned my chain and gears with rubbing alcohol and towels. Afterwards, I applied some chain lube on the chain. Now, when under a lot of torque, the chain skips and slips mid-cassette. Low gears and high gears seem to be unaffected. There were no tweaks made to the front or rear derailleurs. Could the previous gunk have kept the chain centered on the gear? Is there any chance that the rear derailleur got tweaked in the cleaning process somehow? I did clean the two gears on it.

The bike is a 2007 Specialized Tarmac with about 4-5,000 miles on it.

  • UPDATE: Went to my LBS and they told me that given that the cassette is 9 years old it should be upgraded/replaced. They said that there is nothing they can do for the rear derailleur. Is this BS, or true given that the cassette is sooooo old (and probably worn)? – Zlatty May 11 '16 at 18:18
  • Consider keeping better records. A car has an odometer to measure total distance travelled. I use strava, so I know my bike's done 3017 km since I bought it 5 months ago. A chain should be replaced at .75% to 1% elongation. If yours is longer than that, it will have eaten its way into the cassette, and possibly even the front chainrings. – Criggie May 12 '16 at 5:41
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    @Criggle, you do realize that Strava has not been around since dawn of time, right? I am at 3,290.0mi according to my bike's page. However, this is only for three-ish years of using Strava. The rest of the rides were lost in a time where Garmin would save all the data onto the computer, and not to the cloud. PS: See bicycles.stackexchange.com/questions/31397/… where I asked how to find and recover my ancient rides! – Zlatty May 12 '16 at 5:53

It's possible that during cleaning a grain of sand, for example, has become stuck in the chain causing a stiff link which does not travel cleanly over the cogs. Cleaning chains and cogs often involves a significant amount of moving dirt around before extracting it.

A simple test for this is to move the chain through both hands bending every link. You'll find a stiff link very easily.

If that's the problem, clean the link until the stiffness goes, re-lube and you should have no further problems.

  • I think this might be a good idea. I'll take the rear wheel off soak the chain to remove any oil and then test out for a crappy link. Thanks on the suggestion. – Zlatty May 11 '16 at 18:21
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    This is possible, but a stiff link would be an issue in all gears, not just midrange. I thought about a chain pin.which wasn't fully flush, too, but discarded these ideas for that reason. – zenbike May 11 '16 at 18:44
  • @zenbike That could be compounded by extra wear on the midrange gears... – Byron Ross May 17 '16 at 4:30
  • Not really, no. If it was stiff enough to be an issue, it wouldn't matter if the gears were worn or not. It would at least make noise in all gears, even if it didn't skip. And the midrange gears, where the chai line is straightest and the load is most direct would be the quietest/least affected, not affected more. – zenbike May 17 '16 at 4:33
  • @zenbike true, clutching at straws! I've had huge problems in the past with cleaning old, worn drivetrains. They seem to work OK coated with oil and debris, but then you clean them and they become next to useless. It's also possibel that a worn cassette and stiff chain will skip without making noise in other gears. I suspect the OP may be up for a new cassette and chain on a bike that old. – Byron Ross May 17 '16 at 4:39

There are a few possibilities here:

1) Cleaning the cassette took away the gunk keeping a slightly worn cassette from showing. If you use the middle gears most, they may be more worn than the rest. Unlikely, but not impossible.

2) You bent the derailleur hanger or derailleur cage when removing or cleaning. More likely than #1, and easy to test.

3) Check that tour derailleur cables are clean and lubes. This can cause a derailleur to sit slightly out of alignment with the cogs in some gears.

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    Not only that, no. You need to have the derailleur hanger alignment checked/fixed, then the derailleur adjustment, which is mostly done via cable tension. Last, if you still have an issue, look at mew cables. – zenbike May 10 '16 at 18:36
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    Yes. However, if it was fine before cleaning, it wouldn't be the first thing if look at. Ask them what they'll do if the issue is still there with the new parts you bought from them... – zenbike May 11 '16 at 18:21
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    Hmmm. I'll give that a try. It could be that the chain has gotten worn out as well. It's the original train that came with the bike. – Zlatty May 11 '16 at 18:22
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    @Zlatty - The original chain from 2007? Good chance it is worn out. However, before you change it, get a stretch measurement (e.g., Park CC-2). If it is greater than 1%, then the cassette is likely worn too and could slip with a new chain. It is odd however that a worn chain and worn cassette would slip unless the cassette teeth are extremely worn out - which would be very obvious. – Rider_X May 12 '16 at 18:23
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    @Zlatty - most suggest changing 10 speed chains at 0.75%, so the fact you got to 1% to slide in means your chain is definitely EOL. The question is whether the cassette got worn. I have run a 10 spd chain to 1% before and the cassette still worked ok with a new chain so you may be fine. You reported skipping, but as others suggested it may be by a different cause. Try a new chain, adjust the derailleur and carefully check for skipping. – Rider_X May 14 '16 at 4:36

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