I used to have a wheel-rotation-counting computer that save my maximum speed, and used Strava on my e-phone. On several occasions the max speed based on wheel rotation was around 70 km per hr (43 mph) but Strava said my speed was over 80 km per hr (over 50 mph). I have ridden over 50 mph a couple times in the past, but I was definitely not going that fast on those rides. I vote for BS due to inaccurate gps data. Look at the data points leading up to and following the 60 mph spikes and I`ll bet they don`t make sense.