Many three-piece balls have soft, synthetic balata covers surrounding rubber windings and liquid centers.
Most two-piece balls have solid plastic cores and durable Surlyn covers, which combine for a harder feel.
THE FLIGHT PATTERN
Backward rotation forces air to flow faster over the top of the ball and slower around the bottom. This turbulence lowers the air pressure above the ball while at the same time increasing the air pressure below. As the ball presses against the lower air resistance, the result is lift, which gives a well-hit drive the flight characteristics of a jet taking off. As the spin and speed wane, the ball drops (far right).
TWO-PIECE VS. THREE-PIECE
Compared with the softer three-piece ball (top left), the two-piece ball tends to leave the club face more quickly and at a higher angle, with less backspin and a longer roll.
Dimples increase distance (diagram above); for years the straight-line dimple pattern was the most common.
The icosahedron-patterned Titleist flies higher and farther, rolls less and curves more than Tour-rival DDH.
The dodecahedron Maxfli DDH would appeal to the golfer who desires a lower arc and a longer roll.