These Throttle Loose Ball Auminum from Stolen are freestyle BMX pedals with a shaft diameter of 9/16", making them compatible with two-piece and three-piece cranksets. They are made of a very durable and reliable alloy. For strength and durability, the spindle is made of chromoly steel, which won't break easily.Loose ball bearings for those who don't ride in mud and dirt.With big platforms like these, it's easier to catch the pedals after doing a trick that requires your feet to leave the pedals.