E Bike Cassettes. Use this a 1.85mm spacer to allow Airbike/Shimano/SRAM/Fulcrum 8, 9 or 10-speed cassettes to be installed on Airbike, Shimano, Sram, Fulcrum and others 11 Speed hubs. Freehub Cassette Spacer for Airbike/Shimano/SRAM/Fulcrum Cassettes (1.85mm).