SRAM RED XPLR XG-1391 Cassette - 13-Speed 10-46t For XDR Driver BLK/Silver E1SRAM RED XPLR XG 1391 Cassette 13 Speed 10 46t For XDR Driver Black Silver E1. As the terrain gets tougher and the pace gets faster you need the right range to keep moving and the best steps between gears to keep up. The 460% range of the RED XPLR XG 1391 13 speed cassette gives you the climbing gears you crave on gravel and the tight jumps you need on spicy sprints. Enjoy the highest shift quality on even the roughest roads thanks to optimized shift