BMX RIDER BIKE SIZING RIDER HEIGHT FRAME SIZE TOP TUBE LENGTH STEM LENGTH BAR RISE BAR WIDTH CRANK LENGTH GEARING 4'0" & under Micro-Mini 15"-16" Mini 2"-2.5" 20"-22.5" 150-160mm 41-43/16 4'0"-4'6" Mini 16"-17" Mini-Mini XL 2"-3.5" 21"-23.5" 155-165mm 41-43/16 4'4"-4'10" Junior 17"-18.5" Mini XL-Pro 3"-5" 22"-25" 160-175mm 42-43/16 4'8"-5'4" Expert 18.5"-19.5" Pro 5"-7" 25.5"-27" 170-175mm 42-43/16 5'4"-5'10" Pro 20"-20.5" Pro-Pro XL 7"-8" 27"-28" 175-180mm 43-44/16 5'10" & over Pro XL or Pro XXL 20.5" & over Pro XL-Pro XXL 7"-8" 28" 180-185mm 44/16 & over Click Here To Return