Oneup components 1x11 cassette sprocketimprove the backpedal performance of your 11 speed shimano cassette without losing range the oneup 18t sprocket and spacer kit replaces the 17t and 19t sprockets within a stock 11 speed shimano cassette and spaces the cassette out by 4mm which greatly reduces back pedal chain dropping issues three former race face engineers chris john and sam founded oneup together they have over 22 years of bike industry experience and have developed some of mountain b