If you take a membership it does an estimate of your power ouput at different parts of the ride based on your weight and that of the bike don't ask me how it works but I have found it really useful. Oh and downside - I started off trying to whack down my times on certain climbs, but you really just knacker yourself for the rest of the ride. So now I just take each one as it comes and have a go at it legs feel good
Colin