We recommend everyone have a dedicated cycle computer on their trike. Why can't I just use my smart phone? For starters, smart phone batteries are strained enough already. When your smart phone battery dies, then you are no longer tracking your speed and other ride info. A dedicated cyclo computer's battery will last over a year if not longer. Also, the GPS signal in a smart phone is NOT very accurate or precise compared to a dedicated cyclo computer. Also, the interface on a cyclo computer is much simplier and easier to read and access than using an app on a smart phone. Bottom line: if you want a stable way to measure how far you ride, get a dedicated computer.