Shimano shifting problem question

[drssyoon]

I am having a problem on the middle cogs - I think 4th and 5th - where chain feels like it's slipping and jumps from the larger to the smaller, back and forth. This is the only place where this happens, and only with the larger front chain ring. Everything else is fine and well adjusted. Any hints on what could be causing this problem and a way to fix it?

Thanks in advance.

Setup
DA rear der, 9 speed cassette - not sure about the age
FSA compact front - new
Chain - new

[Peter P.]

1. New chain has a stiff link?

2. Derailleur cable is clamped on the wrong side of the pinch bolt?

3. Derailleur cable is binding somewhere such as the BB cable guide or inside the housing. It could also be fraying at the anchor end inside the lever.

4. Those two cogs are worn. To test, try another Shimano wheel, perhaps from a friend.

5. Derailleur hanger is bent.


Those are my first guesses.

[drssyoon]

Good suggestions and will look into them.

BUT, why would the problem occur only during one particular combination of front x rear?

Thanks.

Steve

[Chris]

worn cogs

[dave thompson]

Good suggestions and will look into them.

BUT, why would the problem occur only during one particular combination of front x rear?

Thanks.

Steve
Could be that those two cogs have the most wear. Or that's the area where everything is the most out of spec.

I would tell you to start with the rear dérailleur adjusting procedure from the start, as if you had just installed a new one.

Trying another rear wheel is very good advice. If the problem persists with a different wheel, the fault lies somewhere in the shifting "system". I would start checking for cable binding, particularly at the cable guide underneath the bottom bracket shell. You may wind up installing a new inner cable. If the fault isn't there with the other wheel, then you might have to replace your cogset.

[stevep]

make sure the cable is attached to the derailleur correctly.
its easy to do this wrong