I read on another forum that when mating a Garmin 800 with a speed/cadence sesnor that you enter the wheel size in the Garmin. I find no way to do that. There is no prompt. It makes sense that it would be required since most bike computers require wheel circumference be entered. Was the information incorrect? If not how do I enter it? Please, if you know nothing about a G800 please don't hazard a guess.