Probably the old casting, but still a good tire...

BFGoodrich g-Force Rival S

 

When did they introduce a new casting and what are the differences? I haven't seen anything posted about that.

 

They changed the casting and compound for the brand new tires made in 2016.

It was stated in Grassroots Motorsports Magazine, but they didn't go into much detail, other than it tests better in responsiveness, slightly more grip than the previous casting.

This years times are lower on the new casting as well, but not by much.

Sorry I can't give you much more detail.

 

Ask Andy Hollis. One of his articles in GRM had details on it. I am at work and can't find precisely which issue it is right now.