How do you measure pulley diameter? On v-belt pulleys do you measure the outside diameter, the inside diameter or the pitch diameter? On a serpentine pulley do you measure the outside diameter, the bottom of the grooves or the high points (tops) of the grooves? On v-belt and serpentine belt charts they list two lengths. One is the effective length and the other is the outside length. If for example you measured over several pulleys to determine belt length would this measurement be the effective length or the outside length? I need a quick tutorial from someone in the know. Thanks