shimano 11-speed 1.85mm low spacer shimano shimano cassette spacersfor use on 11-speed freehub body with 9 or 10-speed cassetteusing 10-speed cassette on 11-speed freehub body requires both 1.85mm (fw8991) and 1.0mm (fw4671) spacerusing 9-speed cassette on 11-speed freehub body only requires 1.85mm (fw8991) spacer