On the 1974 TR6 I bought new the G800 Black Walls were standard, but I ponied up for the optional Michelin Redlines. They looked great on my Carmine TR6. The Michelins had tubes and were a required option for cars that came with wire wheels. They howled like bansihes when Autocrossed or thru fast corners, sounded like you were going faster than you were. But the hard rubber lasted forever, before anyone thought about tires being to old to drive on. I belive the Michelin X 185-R15's had old school 78 series sidewalls. The Michelin X 165-R15 black walls were an option on TR3's and 4's