Diamond coated. I liked Harvick’s reply in the post-race interview when he was asked about JJ edging him out for the win. It went something like “I guess he had more holes drilled in his tires then we did”.
NASCAR exec’s seem to be a little touchy about Goodyear tires. I wonder if it’s because Goodyear pays NASCAR 12-17 million a year to be able to run their tires on the circuit? Talk about bang for your (advertising) buck- I don’t know how many times I hear the term “Goodyear” during a race but it’s quite a few. And with NASCAR’s penchant for change involving vehicle styles and specs it makes you wonder why NASCAR has stuck with Goodyear tires for over 60 years when their are other manufacturers out there.
doesn't always pay to be a smartazz
might need to install safer barriers: