Originally Posted by
cxwrench
There is none. They are 100% compatible. The pitch is the same on all drivetrains, all speeds. The only difference is 1/8" (track/bmx) and 3/32" (road/mtb).
Are you sure? I mean the chains were getting narrower ever since ... 7-speed? The FCs are marketed (I understand that may be marketing only) as if it mattered ... e.g. 2x10, 3x11, etc ...