Pitch circle diameter of gear 2 is the diameter of the circle which passes through the centre of all the studs, wheel bolts or wheel rim holes. And is denoted by d2. Pitch Circle Diameter of Gear 2 is usually measured using the Millimeter for Length. Note that the value of Pitch Circle Diameter of Gear 2 is always negative. Typically, the value of Pitch Circle Diameter of Gear 2 is greater than 0.