Quoted message said:Well, I ended up taking it to another shop for a 2nd opinion. The
second shop also could not get the bike to shift to the small cog at
the max limit on the rear derailleur. He took the spacer off the small
cog and put it between the large cog and hub (as a Mavic hub should be
w/a shimano cassette) and put a spacer between the derailleur and
derailleur hanger. It seems work a lot better. The wobble is gone
anyway and it doesn't look "off" any longer.
I'm still perplexed as to why this occurred. Both shops had competent
techs that are experienced with high-end equipment. Thanks everyone
for their help and suggestions.
How old is the rear derailleur? It sounds like it's having difficulty
pulling the chain down onto the smallest cog, which can be caused by a
number of things, including-
- Old worn out derailleur with loose pivots and springs that aren't as
strong as they should be. Also a worn out upper pulley.
- As someone else pointed out, bad derailleur hanger alignment. But,
thinking back on it, could be a bent derailleur as well.
- (Some people are going to hate this one) Sometimes Sachs/SRAM chains don't
shift quite as well as Shimano. This mainly shows up on the front, but
sometimes I've seen cases where we replaced a Shimano chain with an SRAM and
it absolutely, positively brought out the worst in shifting issues.
- Problems in the cable/housing (too much friction). Easiest way to rule
this one out is to remove the cable from the derailleur and push the
derailleur from the smallest up to the second-smallest cog, and then let go
of the derailleur and see how readily it comes back down. If it works great
without the cable attached, could be too much friction someplace in the
cable & housing.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com