Brucey wrote: squeaker wrote:
Samuel D wrote:Our bodies bounce badly by comparison and that is the source of Heine’s suspension losses.
But how does he measure these internal losses?
IIRC he inferred them by coasting downhill over rumble strips and observing the speed change vs riding on the smoother surface alongside. US-style rumble strips are pretty lumpy so it represents an extreme case, but it shows the principle.
The method, according to my memory, was to ride the same length of road repeatedly at a set speed, on and off the rumble strip, and compare power meter readings.
IIRC, the speed was around 17-18mph, the tester being unable to consistently hold higher speeds for long enough when on the rumble strip.
He used downhill coasting for real road (rather than drum) tyre rolling resistance testing.
US-style rumble strips are pretty bad, but not really any worse than the rougher varieties of pavé. The extra 200 -300 W required to maintain speed shows why the cobbled sectors on the Flanders classics are as effective at breaking the aero tow as climbing.