CITY TRUCKS
Skateboard suspension mod for city streets
Solo Project - Oct 2022 to Present | Skateboard Dynamics | FEA | Rapid Prototyping
Overview
Lets ride.
Skateboarding on city streets can be uncomfortable, irritating, and potentially dangerous due to the varying ground conditions and the way the skateboard reacts to them. Commuting skateboards are often overdamped due to the urethane bushings and wheels which may improve ride quality over tiny bumps and cracks but fail to reduce the vibrations induced by adverse road conditions (Large cracks, street car tracks, gravel). These vibrations are directly transferred to the skater’s body which can cause a sense of discomfort and panic.
The purpose of the City Trucks suspension system is to give the skater a sense of increased comfort and control by improving how the board feels when traveling on adverse city roads.
Design Philosophies
Structural Reliability
Cloud-like Ride Quality
Increased Rider Control
Vehicle Dynamics
Or Skateboard Dynamics...
By drawing insight from my automotive background, I decided to apply the principles of a standard vehicle dynamics model to a skateboard to quantify the effects of different suspension retrofit designs. The simplest of all vehicle dynamics models is the Quarter-Car Model. Using that as inspiration, I've developed the Half-Board Model for both standard skateboards and ones with the City Trucks Suspension installed.
Quarter Car Model
Half-Board Model
Standard Skateboard Model
Visual Model
First Principles Equations
City Trucks Suspension Model
Assume the City Trucks Suspension will have spring and dampening components.
Visual Model
First Principles Equations
Taking inspiration from automotive engineers.
Many factors contribute to the smoothness of a vehicle's ride quality. One way to understand ride quality for a skateboard is by recording the skater's deck height over a period of time using the governing equations found for each suspension configuration above.
Deck
Deck Height (Yd)
Standard Skateboard Simulation
Simulink model for a standard skateboard. This will used to benchmark the ride quality of my current skateboards
City Truck Suspension Simulation
Simulink model for a skateboard with City Trucks Suspension. This will used experiment with different dampening and spring rates to find the ideal theoretical ride quality for city streets.
Sketches
Going beyond springs and dampers...
Brainstorming
Right now, I'm experimenting with deformable geometries that can be used to absorb city street vibrations.
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Next Steps
Time to test it!
Complete damping coefficient and spring rate testing fixture to finish the Standard Skateboard Dynamics Model
Fully define engineering specifications based on results from Standard Skateboard Dynamics Model
Devise a list of subjective ride experiences and distinguish which characteristics are desirable and which ones contribute to a negative experience
Begin to study which mechanical qualities of the suspension system contribute to those subjective ride experiences
Experiment with rapid prototyping