The new compound that uses far less petroleum is a first step, but the tires also boast a lower rolling resistance by way of reduced weight. There's also an inner liner in the tire to reduce air permeation of the tread compound. This helps keep the air in the tire, and maintains inflation, dodging the fuel consumption increases from underinflated tires. The most pressing question, though, is what do they smell like? There are scented tires on the market already, but we're guessing that these Yokos aren't going to release clouds of fruity smoke when you peel out.
[Source: Yokohama via autoindustry]