Originally Posted by
walnutz
I’m not a heavy person so I definitely felt I had to work more to keep them going on flats, or on any road terrain in general. I felt like if I stopped pedaling the bike stopped.
Yes, this is scientific; you were after the flywheel effect. Time trial bikes have solid rear wheels for that (and aerodynamic) reasons. This is not a phenomenon that is unique to cycling. Those who have installed aftermarket flywheels in manual transmission cars also go back and forth on this issue.