Originally Posted by
Duragrouch
Please pardon my ignorance on newer systems; There appears to be an additional pivot point just aft of the rear derailleur mount (versus older traditional RDs); Is that a "clutch" that I've heard of on newer RDs, especially for large 1X cassettes?
Also, I sure don't grasp why so many 1X cassettes, are all silver color plating, but the largest cog is black. Is this like semi-auto pistols with a black slide over a chromed frame? I don't see the aesthetic appeal, and I can't think of a functional one.
The pivot aft of the RD mount is not the clutch, but rather the pivot around which the B screw rotates the RD to adjust the height of the top/guide pulley. It is a removable piece (to be removed) for mounting on direct-mount RD frames.
The clutch, here in the off position, is indicated by the red arrow.
On some cogsets, like this Shimano CS-HG500 part, the inner-most, dark grey cogs are made of aluminum rather than steel to reduce weight. This part weighs about 430g while the all-steel CS-M4100 part weighs north of 500g.
11-42T, one alloy cog
11-46T, two alloy cogs