2025-09-16 00:00:00 This is a gear ratio calculation application for bicycles with external gearboxes such as road and MTB. It creates speed-cadence and gear ratio graphs from 22 different chainwheel, 39 different sprocket, and 70 different tire combinations. By turning on and off the display for each gear in the outer center and inner center, you can simulate the optimum gear ratio. This is ideal for helping cyclists who are dissatisfied with their current gear ratios to select replacement parts.