Helix 11 Speed 946 - No backwards compatibility
11 speed Helix parts are not backwards compatible with 11 speed TRS+ cassettes, regardless of generation.
Helix 12 Speed 950 - Yes!
12 Speed Helix 950 parts are backwards compatible with 12 speed 950 TRS+ cassette parts.
The Fine Print - misaligned lock screw
The first production batch of Helix 950 Cassettes included an error in the location of the lock screw. Because of this error, if a Helix steel piece is installed on a TRS+ aluminum section or vice versa, the lock screw holes will not line up!
This includes all Helix cassette parts with date code 39M or earlier. This code will be laser etched on the cassette pieces with the rest of the date code. Where can I find my Date Code?
Helix parts with version code date code 40M or later are directly compatible with TRS+ parts.
Regardless of this hole misalignment, you can still use any Helix parts with TRS+ parts. We have developed a special lock screw to deal with the hole misalignment.
Please contact e*thirteen support if you have this issue and we will be happy to supply you with this lock screw.