Welcome to modern times, NASCAR! Hanging on to old-school technology is nothing new for the traditionalists at NASCAR, and usually it is kind of charming. The fact that the most popular racing series in the world was still using carburetors in their cars until 2012 is a fun little piece of trivia, but an announcement made today still shocked us as the ancient tech being trusted in modern day race cars.
The announcement details the added length to a couple races on the schedule and a change to the practice rules, but the real headline is the switch from bias ply to radial tires. The K&N Pro Series is a long way down from the glitz and glamour of the cup series, but they were still running bias ply tires... in 2017?
You can be forgiven to have no idea what the big deal is, because radial tires have been standard on production cars since the 60's according to this timeline. Some motorcycles still use bias ply tires as they do have advantages in some applications.
A quick recap: Bias ply tires have cords made of nylon or other fabric going across the tire spanning from bead to bead while radial tires have steel cords running around the tire, perpendicular to the bead.
Bias ply tires are harder, which is good for less rolling resistance and durability, but radial tires offer more grip and even dissipate heat better. That is why they are the go-to choice for the vast majority of racing.
Bias ply tires are cheaper to manufacture, however, and that could account for their use in the K&N series. It makes sense to keep costs as low as possible when even the cup series is hurting for money lately.
However, as the demand for bias ply tires goes down (We were surprised there was still any at all) that cost difference will be smaller. That's just economics. So it makes sense for the series to finally step into modernity with some proper radial tires like everyone else has been using for over 50 years.