20% compared to which current tire? The EP100? The EP422 or the new (for Europe and Japan) EP001 S? The EP100 was nearly a match for the Energy Saver A/S in fuel economy. The EP001 S was just released in Europe and Japan and supposed is the first tire to achieve an A/A (AAA-a in Japan) ranking for rolling resistance and wet traction.
And if the traction is acceptable. BTW, any idea what the article is talking about when they say that energy loss in tires is caused by "bulking agent dispersion"?
Energy loss is mainly attributed to hysteresis. When a tire absorbs energy and transforms that energy into heat instead of returning the energy into forward motion (think bouncy rubber ball or rubber band) you lose efficiency. The bulking agent is likely less able to absorb and return energy. So by changing compounds and sidewall design they can create a tire that can be soft riding yet energy efficient. There are generally trade offs for efficiency. Those used to be tire wear and wet traction. With modern compounds these trade offs are reduced such that you can have a pretty darn good tire that is efficient, has great wet traction and lasts a long time. You won't get a full on performance tire but for everyday driving they work great.
