Podagrower

So, it was a nice confidence boost to see top speeds on my ride today of over 90 MPH-that not riding much this summer thing is really paying off-but everybody seemed to have no problem keeping up with me. And covering 33 miles in 60 minutes means this math doesn't work out too good (it was actually 13 miles).

I'm using Map my Ride on an Android phone without data, it is paired to my speed/cadence sensor and heart rate monitor using ANT+, wheel size is set correctly and I think the only accurate readings I got were time, heart rate, and cadence. Does anybody know of a trick to make MMR more accurate? (Does it need network data to be accurate?)