Product Manuals - The Bell Garage Product Manuals. Searching for product information or a manual? Check our online database. Can't find what you need? Our Customer Service department may be able to answer your questions. Try contacting us directly: 800-456-2355 Mon - Fri (9am - 6pm EST) Bell Bike Computer Instructions | Livestrong Bell bike computers are devices designed to attach to your bicycle and record certain types of information, such as the distance you have traveled and the speed at which you move. A magnet and a sensor unit attached to the front of the bicycle track the movements of the front wheel.