1. Express-O Commuter Trike
DESIGN PROJECT PRESENTATION
Department of Mechanical Engineering
Dalhousie University
Halifax, Nova Scotia

2. Team 4 – Express-O Clients Supervisor Dr. A. Warkentin
Dept. of Mechanical Eng.
Dalhousie University
Matthew Rockwell
Matthias Eisengruber
Jayme Whalen
Patricia Gillis
Ahad Ahmed

3. Problem Definition PROBLEM SOLUTION Congested Highways
Increase in Commuter traffic in HRM
Congested Highways
Environmental Pollution
Parking space shortages
SOLUTION
Environmentally Friendly
Reduce traffic congestion
Average business person

4. Express-O Design
Drive Train
Frame
Braking
Banking
Steering

5. Rear Triangle from Bicycle
Frame and Seat
Re-use rear triangle
Adjustable seat
60o from Horizontal
1 3/8” Chromoly
Steel Tubing
Rear Triangle from Bicycle

6. Drivetrain 80 rpm [ Comfortable, Efficient pedal cadence Gearing
3 X 7 Rear drive train
Fixed ratio Front drive train

7. Drivetrain High Gear 1 : 3.5 Gear Ratio
Max 80rpm input: 35 km/h
Low Gear
1 : 0.69 Gear Ratio
Max 80rpm input = 6.8 km/h
Front
Middle
Rear

8. Chain Routing

9. Braking
Dual Front Disc Brakes
Radical© Brand Mechanical Disc Brakes

10. Tilting: Theory Shifts Center of Gravity
Normal Force on inside wheel is increased
Tipping occurs when Normal force = 0 D F mg FF A y x a b FN y y H H

11. Tilting: Theory
Turning Velocity h Stability in Turns h

12. Tilting: Links Thickness of Link – 1” thick x 1.5” high
Holes for bushing and spring housing
Bushing
Horizontal Tilt Link
Diamond Plate

13. Steering: Theory Ackerman Steering Centre Point Steering Caster Effect
Wheel Camber

14. Steering: Rider Input Vertical Steering Arms
Located at both sides of the rider
Can move forward and backward
Connected to L-bracket on bottom of the stub axle

15. Manufacturing Parts needed for Assembly : Qty 88 Parts Tasks:
Acquisition of Material
Off the Shelf – 44 parts
Student built – 32 parts
Technician Built – 12 parts
Dimensioning
Machining
Welding
Assembly

16. Major Design Changes
Tilting System
Materials
Brakes
Drive train

17. Changes to Tilting System
Replaced bearings with bushings
Closer fit
More contact surface
Added springs
Static stability
Return from banking position

18. Changes to Materials
Most parts originally designed to be fabricated from steel
To reduce weight, cost some parts were fabricated from aluminum
These include:
Horizontal tilt links
Steering L-brackets
Steering arms

19. Changes to Brakes Omitted rear V-brake
Vehicle now has dual front disc brakes only
Disc brakes provide sufficient braking power
Simplified the braking system

20. Changes to Drive Train Originally designed to have three derailleurs
Now has two derailleurs
Lower gear ratio

21. Analysis Finite Element Analysis Design Requirements:
Horizontal Tilt Links
Stub Axles
Design Requirements:
Survive:
5Km/H impact with curb
0.16 m drop off curb
Safety Factor: 3

22. FEM RESULTS Max Force: Max Stress: Al 6061 T6 Yield Strength: 1800 N
90 MPa
Al 6061 T6 Yield Strength:
276 MPa

23. Stub Axles Max Force: 1020 Steel Yield Strength: 1800 N Max Stress:
200 MPA
1020 Steel Yield Strength:
346 MPa

24. Future Improvements Horizontal Tilt Link Mounts Chain Pulley Brackets
Spherical Ball Ends
Spring and Damper Set Up
Seat

25. Horizontal Tilt Link Mounts
Problem:
Cantilevered Bolt acts a Pivot
Bolt bends when forces act on Links
Fix:
Second Diamond Plate

26. Chain Pulley Brackets Problem: Fix: Cantilevered Bolt
Bolt bends when Chain is under tension
Regular Idler Gear not designed to run on an angle
Fix:
Second Adjustable Plate

27. Spherical Ball Ends Problem: Fix:
Inexpensive Rod Ends with unknown load rating
Not quite enough freedom to move
Premature Failure
Fix:
Higher Budget to buy specked out Rod Ends

28. Spring and Damper Set Up
Problem:
Springs need to be adjusted according to rider weight for smooth banking
Banking motion is not continuous
Fix:
Adjustable Spring Mounts
Light Damper to “smooth out” banking motion

29. Seat Problem: Fix: Not enough side support
Makes leaning into corners harder
Fix:
Deeper Sling Seat Design

30. Accessories Lexan/Plexiglas Enclosure Lights Flag
More Storage Compartments
Toolkit
Cup holder

31. Original Scope Ergonomics Safety Durability Materials Costs Complexity
Physical Specs
Ergonomics
Materials
Costs

32. Safety Safe to operate Visible in traffic Stable Durable
Protection of rider from moving parts

33. Durability Withstand environmental conditions
This has not been fully tested
Withstand road conditions (i.e. potholes)
Seems to ride well on road surfaces
Survived speed bumps!

34. Complexity Simple & Functional Easy to Manufacture & Repair
Standard “off-the-shelf” Parts
Brakes
Wheels
Chaining
Rear Triangle

35. Physical Specs Original Dimensions Actual Dimensions Width: 1.5m
Length: 3m
Height: 2m
Weight: 50kg
Actual Dimensions
Width: 1.12m
Length: 2.15m
Height: 0.82m
Weight: 29kg

36. Ergonomics Sized comfortably for one adult
Adjustable seat to pedal distance
Seat at a comfortable height
Simple to operate
Intuitive steering
Learning curve to mastering tilting
Easy to Mount/Dismount
Relatively easy – except position of tilt links

37. Ergonomics (continued)
Reduced physical power input
Relatively easy to pedal
Protection from weather
Not included due to time and money
Options for future adaptations
Cargo Space to fit backpack/briefcase
Rack over rear wheel
Extra space behind seat

38. Materials Minimize costs and meet design requirements
Recycled Parts
Donated Material
Light, durable, easily machined
Changed some parts to aluminum
Durability issues with the chaining
Stub axles were the most complicated part

39. Cost
Ceiling price of $2000
Total estimated cost $ ($ with donations)
Actual cost $825.15
Keep cost to a minimum
Donated Material
Recycled Parts
Money Donations
Necessary but expensive parts
Additional costs for bolts, springs, etc.

40. Criteria Table Criteria Satisfied Room for Improvements Safety 
Durability
Complexity
Physical Specs
Ergonomics
Materials
Costs

41. Testing Performance Goals Turning Radius Cruising Speed Maximum Speed
Stability
Stopping Distance
Reliability

42. Cornering / Turning Radius
Goal
Capable of maneuvering on city streets
Test Result
Acceptable turning radius of 15km/h

43. Cruising / Max Speed Goal Test Result
Comfortable cruising speed of 15km/h
Maximum speed of approximately 50km/h
Test Result
15km/h is easily attainable
Maximum Speed obtained of 45km/h

44. Stability Goal Test Result Stable when stationary (i.e. Stoplight)
Stable at high speed
Stable while cornering
Test Result
Stable with the aid of front brakes and practice
Low speed stability is slightly less than desired
High speed stability is as expected
Performs very well at high speeds
“Hugs” tight corners at high speeds

45. Stopping Distance Goal Test Result Maximum stopping distance of 6m
At cruising speeds (~15km/h) : <2m
At max speed (45km/h): 7m

46. Reliability Goal Test Result 1350km/year with minimal maintenance
Chain tension system on the prototype is not very reliable
Tilting linkage would require frequent adjustment

47. Conclusion
Performance 
Size and Weight 
Cost 
Safe 
FUN 

48. Thank You Angus & Albert Paddy Wong & Zack Gus Reed
Sportwheels & Bike Doctor
Dr. Warkentin

49. QUESTIONS?