[ActorNightly]

A super easy way to tell how efficient a tire is going to roll is weight. If you are comparing tires for the same diameter/width/tread pattern, in most cases, the lighter tire is going to roll better.

Tire rolling resistance comes from effectively the rebound damping on the tread. As the tire rolls, the tread on the backside of the contact patch takes some time to rebound, so the tire is effectively always rolling over a bump that is the uncompressed tread the front of the contact patch

The lighter the tire, the less sidewall and puncture material there is, which means that the rebound damping on the tire is going to be less.

[nl]

This isn't right. The difference in weight of a tire in the same class is insignificant (~400g) compared to the bike (~7kg) and the rider.

Indeed based on your explanation the stiffness of the tread is going to be as much of a cause as anything.

[matsemann]

There can be some merit to the fact that the weight in a tire is rotating mass, though. But then you get into thoughts about that the bottom of the tire is technically standing still, and the top of the tire is double the speed of your travel. And does it then matter?

[ActorNightly]

Its a very rough rule, and has exceptions, but its generally works out.

Compare continental gatorskins in 28c vs continental gp5000 in 28c. Gatorskins have more casing to prevent puncture, so they are heavier, but that casing also takes away from the rolling efficiency.