Abstract: - In vehicles problem happens while driving on bumping road condition. A shock absorber or suspension system is a mechanical assembly designed to smooth out or damp shock impulse, and dissipate kinetic energy. The objective of this project is to design and static ,dynamic analyze the performance of Shock absorber wire 8mm diameter of the coil spring. The Shock absorber which is one of the Suspension systems is designed mechanically to handle shock impulse and dissipate kinetic energy. It reduces the amplitude of disturbances leading to increase in comfort and improved ride quality. The spring is compressed quickly when the wheel strikes the bump. The compressed spring rebound to its normal dimension or normal loaded length which causes the body to be lifted. The spring goes down below its normal height when the weight of the vehicle pushes the spring down. This, in turn, causes the spring to rebound again. The spring bouncing process occurs over and over every less each time, until the up-and-down movement finally stops. The vehicle handling becomes very difficult and leads to uncomfortable ride when bouncing is allowed uncontrolled. Hence, the designing of spring in a suspension system is very crucial. The analysis is done by considering bike mass, loads, and no of persons seated on bike. Comparison is done by varying materials DIN 1722 SPRING STEEL(67SICR5), AISI 9255 SPRING STEEL, ASM A228 SPRING STEEL, AISI 1050 STEEL, 8mm diameter of the coil spring to verify the finally best material for the spring in shock absorber. Modeling and Analysis is done using catia and ANSYS respectively.Keywords: Shock Absorber, Coil Spring, Stress analysis.