In the market for a bike computer and looking at the Edge 130 plus, its just about everything I need, plus I like the small footprint. As far as sensors go, will the GPS on the computer give me my current speed? Then all I will need is cadence sensor correct? Or will I need both speed and cadence sensors. I tried reading on the Garmin site, but cant find anywhere about if it reads out speed without actually having a speed sensor if that makes sense!