What is the max cog size that is compatible with SRAM RED or Force eTap AXS™ rear derailleurs? November 13, 2020 14:39 Updated 33-teeth. Related articles Is there a SRAM eTap AXS rear derailleur compatible with a higher max cog size than 33T? Will SRAM RED eTap 2x11 work with a 36 or 42 tooth cassette? Is there a marking or indication on the rear derailleur to know if it is a 36t-max or 33t-max version? What are the main differences between RED eTap AXS™ and Force eTap AXS™? Is there a different eTap AXS rear derailleur for 2x and 1x drivetrains? Comments 0 comments Article is closed for comments.