Originally Posted by
UnfilteredDregs
It is slightly bent, and that is because when this issue first started showing up what was happening is I'd go to downshift in anticipation of a slope, it wouldn't happen until too much torque was on the chain. So yeah, a slightly bent hanger is in the equation, I told them to throw a new one on.
My 6700 was a nightmare to get shifting properly. Turned out the hanger was slightly bent @1mm when I bought it new, just enough to screw up the shifting. If it's bent and you are still able to shift like you are (as crappy as it may be), then your hanger is probably off only a hair and you can bend it back in place. If you have a spare wheel with a threaded axle tip exposed you can make a poor man's hanger alignment tool like I did:
1. Unbolt rear derailleur and let it hang down
2. Screw axle of spare wheel into the hole, it fits
3. Measure distance between both wheels from the brake tracks, top and bottom
4. If both measurements are different the hanger is bent
5. Clamp adjustable wrench on bottom of hanger and gently bend into place until the measurements are the same at the top and bottom
6. Put everything back together and tune it up