Apex 1x12 DoubleTap mechanical shifting, XPLR or Eagle gearing
https://www.sram.com/en/sram/road/series/apex-d1
https://www.sram.com/en/sram/models/rd-apx-152-d1
https://www.sram.com/en/sram/models/cs-xg-1275-b1
https://www.sram.com/en/sram/models/fc-apx-1w-d1
Mullet: Eagle + Road crank and shifters (electronic)
https://www.sram.com/en/life/stories/gravel-gearing-horses-for-courses
Derailleur: Eagle AXS
Cassette: Eagle 10-50 or 10-52 cassette
Crankset (road): 38-42T range
Shift/brake levels: Road eTap AXS shift/brake levers
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38 x 10-52 = 19.4-101 gear inches
40 x 10-52 = 20.4-106 gear inches
42 X 10-52 = 21.5-111.5 gear inches
https://youmecycling.com/equipment/the-ratio-technology-mullet-drivetrain-1x12/
Ratio Technology
The solution, which SRAM does not offer itself, but which seems attractive to many owners of SRAM drives, is the possibility of switching a 12-speed cassette (such cassettes are available from SRAM itself but also from many other manufacturers such as Garbaruk) with SRAM Road STIs . The STIs from the Rival, Force and Red Editions are all designed in the mechanical version only for 11-speed circuits. The solution to this problem comes from the UK: from Ratio Technology.
The small English company is building a relatively simple solution for “the human powered wide-range 1×12 drivetrain”. The central element is a 12-speed ratchet specially developed for Eagle ™ rear derailleurs (including cable router). In 2021, a system is to follow with which you can then switch Road AXS cassettes (with a normal CX1 rear derailleur). This then expands the possibilities again – especially with the new Wider Gearing Cassette.