Testing
Method
The success of the device will be gauged by comparing its performance to two other skateboard truck designs that can be easily acquired for the project. Failure to meet the set requirements will indicate that the design that does not outperform the trucks that are commonly used today and is likely a product that will not sell to distributors. This would necessitate a change be made to the design to correct performance issues.
A successful design will be specifically engineered to account for the physical style differences between skateboarding and longboarding and will not sacrifice any weight while improving maneuverability and control of the board during cruising and speed riding styles.
Step1: Use tape measure and painter’s tape to lay a 15’ x 15’ grid below a video camera outlined with 1’ squares inside the grid.
Step 2: Outline the outside course with cones or more tape. This must consist of a turn at a high speed (Course 1), cones placed four feet apart in a line on a downhill surface (Course 2), and a steep downhill surface with cones in a slalom style with 15 feet of lateral movement every 30 feet of forwards movement (Course 3).
Step 3: The weight of a single truck is taken before the longboard is assembled. This is tested on a scale to one tenth of a pound. Record value in table provided below.
Step 4: From this point on, a complete longboard setup with two trucks is tested. Assemble the two trucks upon the longboard. Attach the 100mm wheels.
Step 5: The center of gravity is measured with three distances. The first is the height of the bottom surface of the longboard, Height. The second is the distance between the center of the front wheels to the center of the rear wheels, Distance 1. The third is the distance between the center of the wheels on the same axle, Distance 2. Record these values in the table provided below.
Step 6: The turning radius is gathered upon the grid mentioned previously. Record a video of three 180º turns riding over the grid as tight at the trucks will turn. Reference back to the video and use the grid to fill in the table.
Step 7: A 300-pound load is tested by standing directly above the truck with additional weight. This is recorded as a pass or fail in the table. Note any deflections or discrepancies upon the truck.
Step 8: To compare the maneuverability, rank the truck set on a scale from 1-5 (worst-best) on each of the three courses. Add any additional notes on ride quality in the table as well to compare results later. A guideline has also been provided in the appendix to help fathom the scale.
Step 9: Repeat steps 3-8 for the remaining two truck types.
Results
The requirements listed in the introduction of this proposal account for the weight, center of gravity, turning radius, loading, and overall control. Each design was graded by the following methods in order to assess the success of the NG-Truck. The tests were conducted in a controlled and repeatable environment to ensure collection of reliable data. The maneuverability of this design was tested on a grid outlined with tape and equidistance between each line. This grid was directly below a recording camera to give accurate measurements of the testing area. A series of volunteers have ranked the different truck designs on unique terrain areas to gain the final value. Once the data in the testing procedure below is gathered it will be compared with a combination of graphs and images.
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A successful design was specifically engineered to account for the physical style differences between skateboarding and longboarding and does not sacrifice any weight while still improving maneuverability and control of the board during cruising and speed riding styles. The center of gravity was able to be spread out by an average of 36%, providing a more comfortable, stable ride. Further enhancing the ride, the turning radius was able to exceed the expected maximum turning radius of six feet by a total five inches. Even with this turning ability, riders noted that they had almost no feeling of the board sliding out from under them. This quality is due to the leaning motion the trucks create with cornering. Although the NG-Trucks barely met the five-pound weight requirements and were 47% heavier than the competitors, the design was tested using Inventor to show that there are safety factors over 100 in some places. This shows that many of the steel parts can be made out of a high grade aluminum alloy which will also ease the manufacturing process.
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The NG-Trucks were engineered to extend the center of gravity’s area to 438 square inches while maintaining a tight turning radius of just 6 feet. The trucks were designed to have a safety factor of at least three yet managed to yield a result well above 100 in some places, showing no visual displacement at the 300 lb. maximum load. This allows for further optimization of the weight requirement that was just barely met of five pounds. This design was able to lower the ride height by an average of 17% or 0.85 inches compared to the competitors with oversized wheels. Additionally, the design further allows a decrease in the ride height if a larger wheel was made for the trucks due to the trucks allowing assembly in four different ways. With 100mm wheels being the only sets readily available on the market, the trucks have to be set at their highest setting in order to provide enough clearance below the board. It is estimated that the design can handle wheels as large as a small bicycle.
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It is important to consider that although these are the results for this set of trucks, results will vary with other sets of Traditional Kingpin Trucks and Reverse Kingpin Trucks. For example, the set of Traditional Kingpin Trucks used in this procedure had quite a narrow wheel base. This brought the wheels much too close to the longboard deck, causing an interference issue due to way the Kingpin design brings the wheels closer to and further from the deck to turn. This interference is the reason for the poor results seen in the testing procedure.
