It is very important to design the piston as light as possible as the lightweight piston is a major factor to determine the engine response. Also superior to reduce the impact force during each crankshaft rotation and to reduce the burden on the metals. However, the lightweight and high rigidity are opposite factors and it is hard to contradict them. Therefore, the piston parts that won't affect the strength were lightened as much as possible and not only Rib type design that balances durability and lightweight was used around piston pin boss, but also Slipper type design was used to make the piston skirt as short as possible.