20 TEETH FREEWHEEL SPROCKET COG FOR ANTIQUE ROADSTER BIKE SINGLE SPEED CYCLESLARGE 20 TEETH FREEWHEEL ( ALSO CALLED A SPROCKET OR COG ) IS SUITABLE FOR ANY BIKE NEW OLD , MODERN , ADULT ,RALEIGH, TRIUMPH BSA,RUDGE, ETC ETC ETCLARGE SIZE TO PROVIDE A LOW GEAR RATIO WHEN RIDINGWORKS WITH A NORMAL 1/8″ CHAINCOULD BE USED ON CYCLES OF ALL SIZES AS WELL AS ADULT BIKES, TRIKES INCLUDING FOLDERS, SHOPPERS ,TOURIST BIKES ETC