1. Detailed Design Presentation
Mini Baja Suspension Group
Rob Johnson, Cheng Jin, Robert Perry, Eric Petersen, Ryley Nelson
Senior Capstone MET/MENG 490A

2. Introduction
Baja Suspension Team
● Design and Build Suspension System for
Eastern’s SAE Mini Baja Vehicle

3. Needs, Functions, and Features
● Minimum 10” of travel, front and rear
● Adjustability:
o Ride Height
o Suspension Stiffness
● Sustain 3’ jump without bottoming out
shocks or breaking related components

4. Final Specifications
● 11” of travel, front and rear
● Designed to withstand:
o 4’ drop onto 4 wheels
o 2000 lb horizontal impact on each wheel (front to back)
○ Lowest factor of safety present: 2.34
○ Maximum factor of safety present: 5.1
● k values for shocks:
o Front: 160 lbs/in
o Rear: 200 lbs/in
● Ride height (distance from lowest point of vehicle to ground):
o Max: 17 3/16”
o Min: 10”

5. Description of Solution
● Dual A-arm style control arms front and rear
o Allows full travel of suspension w/o interference
o Creates optimum camber angle for entire travel
o Light weight
● Adjustable ride stiffness and height
o Location of pushrod connection on cam dictates this
● Designed optimum geometry so that each
component can withstand required loads

7. Front Upper A-Arm (Drop Force)
Vertical Force - 800lb
Factor of safety - 2.764
Max Stress - 22.8 KSI

8. Front Upper A-Arm (Frontal Impact)
Horizontal Force - 1000lb
Factor of safety - 4
Max Stress - 15.8 KSI

9. Rear Upper A-Arm (Drop Force)
Vertical Force - 800lb
Factor of safety - 2.47
Max Stress - 25.5 KSI

10. Rear Upper A-Arm (Impact Force)
Horizontal Force - 1000lb
Factor of safety - 2.34
Max Stress - 25.5 KSI

11. Pushrod Buckling (Max Force)
Force - 1500lb
Static FOS > 5
Buckling FOS - 4.47

12. Front Cam Analysis
Force - 1500lb x 2
Von Mises Max - 12.9 ksi
FOS- 2.8
Material- A36 ¼” plate

13. Rear Cam Analysis
Force - 1500lb x 2
Max Von Mises - 13.8 ksi
FOS- 2.6
Material- A36 ¼” plate

14. Front Carrier Analysis (Drop)
Force - 800lb
FOS - 5.1

15. Rear Carrier Analysis (Drop)
Force - 800lb
FOS- 4.987

16. Summary of Evidence
● Hand calculations provide evidence of
o Forces at wheel (worst case, 4 foot drop)
o Force thru carrier bearings/hubs (worst case)
o Force thru pushrod (worst case)
o Force thru cam (worst case)
o Force into spring and required K value (worst case)
● Solidworks modeling provide evidence that
o Needed suspension travel is achieved
o Suspension geometry is desirable through full motion
o Factor of safety in weakest member is 2.34
○ In rear upper A-arm when dropped from a height of 4 feet

17. Budget and cost analysis

18. Schedule of Milestones and Major Tasks
Start: April 1, 2015
Finish: May 29, 2015

19. Questions?