hi, im changing my sprockets to 18/38 cause im turning too much rpm for the speed im going, stock for me is 18/46, way too much rpm, i know these bikes like the high rpm but i want to have the bike around for a few years also, i then went to 18/43, not bad but still tooooo much rpm, im now waiting for 38 rear sprocket, see how that works for me,,,mikey 440