Early Races were being primarily timed by stopwatches mounted to auto dashboards, but because the complication was shrunk, they had been a lot more typically seen on wrists, especially in the F1 and endurance racing heyday in between the ’50s and ’70s. Impressed by British pilot’s watches with the seventies, https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/