So much trust in so little matter… my bike weighs less than two 10lb. weights, the tires have a combined contact area of about 1 square inch, other than a plastic helmet, thin lycra covers my body.  Strava says I hit 52.3 m.p.h., in 39 degree weather.  My palms sweat as I add all that up… because my rear tire was flat when I unloaded tonight.