It hasn’t been officially branded a high value data set by the Dept. of Transportation yet, but the Uniform Tire Quality Grading System, which provides results on federally mandated tests done on tires by manufacturers to check for things like traction performance and tread wear, is on Data.gov now. (A number of stories have mentioned it though, including this one.)
It’s a big XML file; I’ve downloaded it and started poking around in it. Surprised they haven’t released it in a simpler format — this could be useful for consumers shopping for tires, but not if you can’t sort it by brand, or temperature resistance, or traction performance. Most folks won’t be able to do that with an XML file.