The xt m8000 11 speed cassette from shimano is a new high performance 11 speed dyna sys ii cassette it uses hyperglide sprockets that have computer designed tooth configuration with contoured shift gates this allows crisp smooth shifting even under heavy loads the close ratio gearing means you get a more efficient use of energy through the finer cadence control the sprockets are cut away and drilled to reduce weight without reducing rigidity and the largest sprockets are mounted on lightwe