Kerry Irons said:
Unless you can feel a lot of friction in the hub bearings when you turn them by hand, it is not the hubs that are making this difference. For that matter, unless you have done repeat time trials with both sets of wheels (using the same tires at the same pressure on both) then you really have no data to support this statement.
I think Sprocket - Matt was just going by feel. But you’re right, his opinion is just that. And if you want to parse it he didn’t say the Shimanos don’t roll as fast. He said they don’t _seem_ to roll as fast, which emphasizes that he is giving his opinion. I bet he’s feeling something, though, whether it’s increased rotational mass, increased aerodynamic drag, a difference in tire pressure, a difference between early and late season physical condition, etc.
And in truth, the method you describe wouldn't be considered a way of getting valid data, either. You'd need a double blind double screen test, conducted by and measured by machine (humans are way too unreliable), on a statistically significant sample set, under laboratory conditions.
It would be nice if Road Bike Review had the resources to conduct those kinds of tests, but for right now we’re stuck with peoples’ opinions, flawed as they are.