Gates Carbon Drive is the high-tech belt drive for bicycles, motorcycles, & scooters. This app measures belt tension sonically. Just pluck your belt like a guitar string and use the microphone on your phone to read the vibration frequency. Compare your bicycle belt’s frequency to the included chart to see if you need to adjust the tension. For scooter/motorcycle tension recommendations, compare to your vehicle owner’s manual.Other available features for bicycles: Interested in key parameters of your bicycle belt drive like speed ratio or center distance? Want to know what belt lengths or sprocket sizes will fit your bicycle? What about comparing one bike to another to tweak your ratio perfectly? With our calculator, you can stay on top of the perfect setup for your drive.- Find key parameters of your drive such as speed ratio and center distance.- Change belt length or sprocket sizes to better suit your riding needs.