I suspect that the #s MFP gives are based upon really heavy bikes...hybrids or even mountain bikes. All of the cyclists who frequent MFP claim that the # MFP gives them is WAY higher than what they get if they wear a HRM. MFP also considers 16-20mph cycling to be "very fast" and that's their highest effort/speed designation. 16mph would be very fast on my CX bike with knobby tires, but on my carbon road bike (which weighs 3-4# less) that would be a relatively moderate pace for me.