This cross-section is of an R-compound tire. R-compound tires, some DOT-legal, are not actually meant for highway use. Much less steel is used to reinforce the tire, and the rubber is much softer. This is why this type of tire is great for autocross and road courses, but is not recommended for the street—it’s not just because the tread pattern is different. They also lack wet performance and ample treadwear rating.