Unit 91 Week 6 Presentation

1. Selection Analysis Unit 91 Week 6 Presentation Jon Gutierrez, Chris Sauer, Simon Radomski, Chat Huynh, Jeff Burton, & Robert Platt September 24, 2008

2. Last Week • Patent Presentation • Problem Statement Update

3. Baseline: Ellsworth Dare • Nearly vertical wheel path • Small amount of chain extension to limit pedal feedback • Claims a 4-bar linkage allows this

4. Baseline: Ellsworth Dare • Selected because the Dare is a successful bike that exhibits long rear wheel travel “Linkage” Simulation of Ellsworth Dare

5. Parallel Linkage • Chain extension is similar in amount to the dare but acts over a longer distance. • Setup allows an additional 4” of rear wheel travel which reduces the Maximum force transmitted to the rider during a landing. • Double parallel shocks allow increased force dissipation during a landing.

6. Progressive Suspension • Using a series setup for the shock could allow tuning one shock to handle regular riding while the other shock is only used in extreme conditions like landing a jump. Resulting in a progressive suspension rate. • Problem is that this may destroy one or both of the shocks during a landing.

7. Parallel Double Shock • Two shocks integrated into the upper suspension arm. • Must use non standard shocks to attain required travel. • Shocks are integrated into upper suspension arm lateral stiffness of the rear wheel will be impacted. Uncompressed State Pivot Chat Huynh

8. Design Selection Result: Select Parallel Linkage Second Place: Progressive Suspension

9. Analysis of Results • Safety / Force dissipation characteristics are most important • Four Bar suspension improves lateral stiffness • Double shock design improves shock reliability by reducing loads to each shock • Chain Extension and Pedal Bob can be minimized when instantaneous centres coincide which can be achieved by a four bar design The Parallel linkage design that was selected

10. Next Week • Mid-Term Presentation • Review of Status • Mockup of design