A Video-Based System for Measuring the Braking Performance of a Bicycle

The following article describes a methodology for using a video-based system to measure the deceleration or braking performance of a bicycle after the rider applies the brakes. The bicycle’s deceleration was calculated from the equation of motion using the initial velocity and the braking distance, which is the difference between the point of brake initiation (POBI) and the bicycle’s point of rest (POR). The POBI was determined by using a GoPro camera mounted on the chain stay near the rear axle that captured a brake light wired into the rear brakes while the test cyclist rode alongside of a 100-foot surveyor tape. The POR or more specifically where the rear wheel stopped was documented next to the 100-foot surveyor tape. This methodology was evaluated under two braking conditions: rear brake only (RBO) and front and rear brake (FARB). The results demonstrated that the video-based system provided reasonably accurate measurements, on the order of 5% for assessing the braking performance of a bicycle for speeds in the range of 15 miles per hour (mph) or less. Additionally, observations regarding skid marks and rider technique during braking are also discussed.