Mechanic note: The puller tool pulls the arms on the spindle then tighten the crank arm bolts to finish the install. 3-pc cranks take 9/16" pedals. The treaded cups are right and left side. The drive side or also called sprocket side and tightens in a counterclockwise wise direction. These are real Profile cups and bearing so you can tell them apart. The drive side cup has a line engraved around the cup. The crank arm spacers are used to get your chain aligned with your freewheel and sprocket while allowing clearance from the chain stays on your frame.