I was 4 motorcycle with a calibrated meter has Speedohealer, I opted for this app to see
I usually do it with a gps tomtom or Navigon, a mob to another must mount / unmount the handlebar holder
and when that is not possible, it is system D. pfffffff
acquired by conscience on 2ère I do with the app + tomtom and values are identical
now it will be with the app by placing the smartphone on my forearm with the aid of an armband case
driving a wedge 50, 70, 90, 100, 110, 130 and% difference meter / gps, setting and that's life has real speed.
This is useful when changing the gear ratio / crown or rim diameter, the already optimistic counter becomes crazy