Optimum speed for a putt as it reaches the hole on a flat green is 1.5mph, best thought of as the ball hitting the back wall of the cup.
This week’s putting tip is an excerpt from our book, The Fundamentals of Putting., written to help you eliminate 3-putts and transform your putting into the strongest part of your game.
franklygolf 
Frank, this advice seems to be at odds with the idea that if a ball comes to rest within an inch of the cup, gravity takes over and the ball drops in the hole—effectively the cup becomes larger. Hitting the back of the cup requires a fair amount of speed, wouldn’t that induce an awful lot of lip-outs?