If you don't have the numbers, it doesn't count, right? Install Avenir's 9-function Computer, and you'll never have to guess again. It gives you all the basic functions, and a few advanced ones, like speed, distance and calories consumed. The 1-button operation easily scrolls through the screens so you see only what you want to see. With its dual-tire size capability, you can switch it between bikes. It's housed in a water resistant case and uses high-precision cables for longevity.