yeah, they've been using dual compound tires for about 10 years vnow.
started out as a way to make a tire for daytona that would last on the banking and left hand corners but still have grip on the right handers.
Daytona has such a serious tire issue because heat is generated and kept in the tire on the banking and a majority of the turns in the old layout were left handers, so the right side of the tire would cool off and then have no grip.
to compensate Dunlop first introduced dual compound tires to have a harder more durable compound on the left hand side and in the middle, and a softer, more grip right hand side.
there has even at one point been a triple compound tire (dont remember who made it) but it was determined that it was not effectively better than a dual compouind tire to warrant the extra labor and expense in manufacturing.
BTW, there are some tires on the market for street use that do utilize dual compound technology, where there is a harder more durabel center compound, and a softer more grip compound on the edges.
Michelin, Pirelli, and DSunlop all offer them in the sport touring lines, but i'm not aware of a true Dual compound tire in street sport tires.
the funny thing is on the dual compound slicks, you can actually see the line where they join, and feel the difference in many cases....
the thing is, they can now better tailor a tire to a specific track (like PPIR) where they use a certain compound for the softer side, and then at another track, they use the same harder compund, and mix it with a medium compound to tailor directly to the track.....
taqlk about confusing...
"I'll take the medium-soft / medium hard for first practice on the rear with a soft front. But for second practice i want to try the medium/medium hard rear with a medium front then a medium/hard with a soft front......"
too many choices for my simple brain.
"Is it round?"
"does it hold air?"
"i'll take it!"