Document Type


Date of Degree Completion

Spring 2016


Mechanical Engineering Technology

Committee Chair

Charles Pringle

Second Committee Member

Roger Beardsley

Third Committee Member

Dr. Craig Johnson


The purpose of this project was to develop a rear suspension system to support the frame of an Electrathon Vehicle. The vehicle is designed to compete in the Electrathon America competition on behalf of the Central Washington University Electric Vehicle Club. The suspension system was designed to use readily available parts sourced from manufacturers to keep the components serviceable. Using dynamic and static engineering analysis (spring equations, equations of equilibrium, stress calculations), the necessary custom components were designed. Space restrictions and limitations of the preexisting frame necessitated modifications, such as the straightness of the frame and the positioning of existing bars. Once the parts were sourced, received, inspected, and assembled to the existing vehicle frame, minor modifications were made to better accommodate use of the automotive “dune buggy” coil-over spring and shock absorber assembly. The system is over-sprung to take advantage of future weight changes to the currently-incomplete vehicle. With respect to ethical engineering standards, safety is paramount. By anticipating weight additions and designing the assembly with a factor of safety, the suspension system will remain intact and safe for future students that have the opportunity to work on the vehicle. The result of the project is that the coil-over assemblies mounted to the frame as intended. They articulate through the range of motion as dictated by the calculated parameters and design requirements. Overall, the project was a success in that the system is easily serviceable, reliable, safe, and functions as designed.


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