Interesting group riding potential hinted: a group of riders could synch their devices to share real-time information, such as a team in training, or in competition (if they could ignore the large device on the handlebars, at least). The team stats could be shared with a support vehicle nearby.

Or a tour group could use them for ride maps and cue sheets, notify the other nearby device (or perhaps 3G or 4G?) of their locations and status (stopped; moving), perhaps with real-time location pins on a street map, and enable suggestions to pop on the screen for historic or commercial points of interest; post IMs for breakdown assistance.