Unit 91 Week 6 Presentation Jon Gutierrez, Chris Sauer, Simon Radomski, Chat Huynh, Jeff Burton, & Robert Platt October 8, 2008 Post Mid-Term Review

Last Week Midterm Presentation

 Shocks for the seat? o Rider is in a standing position when land  Possibility of pedals hitting the ground? o Pedals are level when the rider lands.  Will each spring take half the force/energy from landing? o Because of there parallel placement each spring will split the force / energy. Questions / Comments

 Will the shocks compress when a rider sits on the bike? o Traditional long travel bikes are designed to compression about 30% when the rider sits on the bike. Our bike will compress about 30% when the rider sits on the bike.  Safety Factor? o 2.3. Which is based on the shoulder bolt’s 60 % tensile strength  Max drop height? o Be able to accomplish a 30 ft jump and land safely on sand.  Weight range of rider? o Max of 230 lb Questions / Comments

 How will the rider weight affect the product performance and life? o The spring rate for the shocks will depend on the riders weight. A heavier rider will decrease the bikes life because of higher forces.  How will all the moving parts affect the products life? o The rider will have to do regular maintenance to check whether the bushings need replacement along with the bolts being tight. The frame should be checked for cracks regularly.  Device for keeping the shocks from bottoming out? o An elastomer will be included in the shock to keep it from bottoming out  How is wheel traveled measured? o The wheel travel is measured vertically Questions / Comments

 Is this safe? o Mountain biking is a dangerous sport, but our bike should be as safe as traditional bikes.  Materials? o Steel, aluminum or possibly titanium  Is it hard to pedal on flat surface? o The bike is heavy and not designed for riding uphill. The mission of the bike is for downhill mountain biking  How will the prototype be tested? o A static load test will be used to test the product. The bike will also be ridden by the team members Questions / Comments

Diagram Static Load Test Jack Apply Force Scale 750 lbs Travel (in) Force (N) Hold Frame Fixed Measure Force Characteristics –Since the frame is fixed this would simulate the force that would be applied to the rider through the pedals –Test would apply force slowly so the effect of the damper would be negligible. 10”

Impact Test ??? Time of Impact (mS) Force Hold Frame Fixed Further Development Needed Characteristics –Very short time period – milliseconds –High Impact Forces –Difficult to apply force –Difficult to accurately measure response Spring Force Force to Rider

Conclusion Class comments are useful but our design has already compensate for most of the comments. We have started to devise reasonable testing procedures but more work is required to develop tests that can fully profile the capabilities of the prototype. Based on class comments, there is no need to revise our design at this point. With the exception of some design criteria graphs the class understood the presented design.

Next Week Layout Drawings