Originally Posted by DScott
The replaceable derailleur hanger on my Trek 1200 has bent...
The LBS mechanic straightened it once using the DAG-1 and it seemed to be better for just a little while, but it is once again listing to port. There's about 2500 miles on this bike, and I'm a little surprised this has happened. I haven't dropped it or banged in to anything on the right side,
AFAIK.
It's surprisingly easy to bend one of these without realizing it.
Originally Posted by DScott
I'm pretty good about keeping the chain clean and lubed.
This has nothing to do with it.
Originally Posted by DScott
I suspect that the chain line is the issue,
No, chainline has nothing to do with bending derailer hangers under any circumstance.
Originally Posted by DScott
... I spend most of my time in the middle of the cassette (15, 17, 19 cogs), I think this puts the rear der. under a fair bit of tension. I'm afraid that is what bent the hanger.
Definitely not. Chain tension is highest in the larger sprockets, but normal derailer chain tension never has anyting to do with bending hangers.
Originally Posted by DScott
My questions are these:
1. Can this kind of chain line tension bend the hanger? Hnagers are soft, maybe it's just worn out?
Definitely not.
Originally Posted by DScott
2. If/when I replace the der. hanger, what's to stop this from happening again?
You need to be very careful not to bash the derailer hanger. Are you
sure it's actually bent? Maybe its the derailer that's bent...
Originally Posted by DScott
3. Would a new chain/cassette help?
Definitely not related to the bent hanger, but it might help in other ways if the old one is worn out.
Originally Posted by DScott
4. My goal is a compact crank setup (with the next bike), but I'm now even more worried about chain line problems. Does this kind of problem happen with compact (or any double) cranks?
Compact cranks are no more subject to chainline probems than anything else, and generally less than triples.
Sheldon "Barking Up The Wrong Tree" Brown
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