Originally Posted by jur
I wonder if this doesn't come out in the wash: Yes you are correct that there is small variations in speed due to varying pedalling torque in a full revolution (see post #9); so a wheel does indeed have to be re-accelerated. However, a heavy wheel's bigger angular momentum will reduce the slowing by a small amount compared to a lighter wheel, so has to be re-accelerated by less.
Perhaps but I don't think so. Angular momentum is considered to be a small percentage of the force at work here with most of the force at work being aero drag at speed. Since aero drag continues to get greater with more speed, I think any advantage a heavier wheel gains from angular momentum during the deceleration phase would get smaller and smaller as speed increases.