Ghost Shifting at the 17 Tooth Cog

[dirtdigger88]

A while back I was playing on my rollers and got a bit out of hand- long story short I went down on the rollers- not hard- but down still the same. I checked out the bike- it seemed fine- Shortly after I noticed some ghost shifting near the 17 cog- In that a shift from 16 to 17 results in some clicking- so I know the derailer is moving some- just not enough. I shift up again and the chain jumps right to the 18. A shift down from 18 to 17 gets the same clicking of the chain but no movement until I shift down again which jumps me to the 16. As I looked into this at first I discovered my cable housing had a small crack in it where it enters the rear derailer. The shop changed out my cable for me (I rode in to buy one and they offered to change it for me while i waited) so thats been fixed- but the ghost shifting is still there- Every other cog shifts crisp as the day I got the bike- I have tried fine tuning the barrel adjuster- but it doesnt help the shifting from 16 to 18- after I move the adjuster far enough either way shifting becomes bad on the other gears but never improves from 16 to 18- I am wondering if I didnt maybe bent my derailer- I am looking for some other ideas or what to look for to tell if I did bend it? It just seems odd to me that everything is fine from 11 to 16 and 18 to 23?

Jason

[CJH]

Hi!
Sorry to hear about your spill on the trainer. Do you know if you fell on the derailleur? Or at least did you lay the bike down on the drive-side? Anyway I read about someone haveing similar issues with shifting at one specific cog. It was suggested that the derailleur alignment be checked! So perhaps that's a good starting point?! But if you on the other hand didn't fall on or towards the derailleur then perhaps the issue is with the shift lever? Anyway good luck!

[mad_mark]

Check wear on the 17t. If you use it the most that could be enough.

[dirtdigger88]

Check wear on the 17t. If you use it the most that could be enough.


doesnt seem to be super worn- the cassette is only a year old- and I have changed chain once

and yes I did fall on the drive side- I can only guess that I did hit on or near the derailer since I broke the cable

jason

[M_A_Martin]

Check both your derailleur *and* your derailleur hanger for alignment to see if you bent them Jason.

[David Kirk]

Sounds like a bent hanger to me. Is this the Legend?

Dave

[dirtdigger88]

Sounds like a bent hanger to me. Is this the Legend?

Dave

yup-

What do I do Captn' Kirk- and why does it show up only around the 17


jason

[coylifut]

the weakest link in this equation is the derailer hanger bolt. I would be surprised if the hanger on a top quality ti bike bent before the bolt. Have the alignment checked and if it's ok, suspect the bolt.

BTW. I once went over to a friends house (this was about 25 years ago) and found him semi concious in his garage. He'd crashed on his new set of rolers. We suspect he'd been laying there for about a 1/2 hour. This falls under the "had to be there" catagory, but if you knew him, none of this would surprise you.

[M_A_Martin]

Park makes this derailleur hanger straightener tool thingy Jason...(they seem to have a tool for just about everything don't they...) I'm surprised you don't have it already :banana: (you mountain biker you!) I tend to crash drivetrain side down and I've found it very useful at times. You could borrow mine, but that's a bit of a drive...I'm sure your local shop has one too.

:)

[Peter]

Besides checking the derailleur hanger as all the other good posts suggested, try swapping out the rear derailleur with a compatible one a kind friend will let you borrow from their bike. That will confirm whether the derailleur is ailing.

Check to see if the cassette is on tight. I've seen lockrings come loose, allowing the cassette to float a small amount on the freehub body; you can feel the play if you grasp the cassette and try to wiggle it with your fingers. This small amount of play can drive one nuts with mysterious shifting problems.

Also, ensure the rear wheel is sitting properly in the dropouts.

[Tom]

I bet that this isn't what it is in this case because you mention the mishap with impact, but I had the same thing and it was a cable adjustment. Why my shifting was odd on one cog when it was a cable adjustment is beyond me, I would have thought it would have affected all the shifts but a turn of the adjusters (in the right direction, after I screwed it up and went the wrong way and buggered all the shifting) fixed everything.

I'm no help, but I've had my coffee.

[davids]

This suggestion might seem to be incredibly obvious, but - Have you checked to be sure the 17 cog isn't bent? I made this mistake once, pursuing all sorts of esoteric solutions to a shifting problem. Finally, I looked at the cassette while spinning the rear wheel - The problem was apparent, to put it mildly... :crap:

Good luck!

[dirtdigger88]

I got it fixed- I pulled the cassette this morning- checked all the teeth- they were all fine. I pulled the chain and soaked it in degreaser then lubed it- I also pulled the derailer to check if the hanger or the bolt was bent- both checked out ok- I pulled the cable- cleaned and lubed it as well. Checked out all my adjustments one last time then bent down and pulled hard on the derailer towards me with firm but even force- I then went out for a ride- I finished dialing in the adjustments at the barrels- NO MORE GHOST SHIFTING- I had it stopped my 5 miles and didnt touch it for 35 more and all was working great- thanks for all the replies of help- What it came down to I am sure is a combo of a lot of little things but I am sure the yank on the derailer didnt hurt- :p

jason