I like the way you said that. To expand and generalize...
Aggressive treads with more voids are less efficient and more void generally equals more noise. So the louder the tire the less efficient.
This might be easier to measure in our ears than at the pumps. I've thought of trying to measure interior tire noise with a decibel meter but have yet to buy the tools and take the time.
Yesterday I mounted my conservative Maxxis Bravo ATs on my stock wheels. They are certainly the most conservative and quiet truck tires I own compared to the louder Cooper ST, and loudest Maxxis Bighorn & BFG MTs, all in 255/85R16.
Though I like to look at aggressive tires on my wheels when stopped, when tooling down the pavement I prefer a quiet, smooth tire.
ntsqd said:
Similarly, though not to nearly as great an extent, if you hear tire noise you are hearing wasted energy. It is what drives this anal Engineer to only use A/T's and not M/T's.