This has been a particularly hard year for me at Northstar with regard to bike damage. Rear derailleurs in particular. Several of the lines on the trails have been the bane of their existence. I think I’ve gone through at least six derailures in 10 days on the mountain. Horrible stuff.
I had started with ZEE short cage on my bike but I’m now using Deore RD-M615 mid-cage. The lower cost was the driver of this decision. It turns out that there are other good reasons.
* Improved chain tension with the mid-cage over the short cage.
* The outer plate has a support that the Zee doesn’t have. A big problem this year has been bending outer parallelogram plates. Hopefully the Deore will prove not to do this. (see pics)
With some parts of a few dead derailleurs, I was able to put a working unit together. A Deore ZEE hybrid.
While doing this work, I chose to use the higher tension setting (of the two) for the pulley arm spring. The mid-cage come set soft and the short cage come set firm. This is different than the clutch. Doing this with the mid-cage setups could add to cable snapping as it will push more of the bump forces to the parallelogram spring. I’m testing this to see.
The clamp plate is filed to reduce cable failure.
For any small cassette setup, the DH rather than FR arm is used for improved shifting.
A problem that I’m seeing on some derailleurs is a failure in the clutch mechanism brackets. I’m looking into this now. A manufacturing or engineering problem for sure.
The bent outer plate problem.
I’m seeing this on ZEE and SLX derailleurs. The outer plate is easily bent and causes the derailleur to twist. You’ll know this is the problem when you don’t see any issue with the hanger or bracket but the twist is obvious.