Has anyone tested the accuracy of the speedo set to mph? It sure seemed to me on full throttle going 20mph wasn't 20mph, could just be my perception. seemed like 15mph or a little under. I don't have a way yet to set up my smart ph for gps yet and need to learn how to do it. Need to figure out how to mount smart ph to bike also, not much room on the bars at all. Plus the bars varying in thickness makes an issue too.