Dr. Diandra: Charlotte’s 600 miles test man more than machine

This weekend’s 600-mile outing at Charlotte Motor Speedway is NASCAR’s longest race. It’s the ultimate stock car challenge: not just making a car fast but making it fast for a long time.

Although 600 miles is nowhere near the 3,300-plus miles in the 24 Hours of LeMans, the pace is similar. Most of NASCAR’s 600-mile races run between four and five hours.

The 1960 World 600 set the record for this race, requiring five hours, 34 minutes, and six seconds to complete — and it had only eight cautions. The second longest race, the very next year, ran 12 minutes shorter than the previous year’s outing.

The longest race in the modern era (1972 to present) happened in 2005. That race took five hours, 13 minutes, and 52 seconds to complete and set a record for cautions with 22.

Last year’s event was the second-longest modern-era race. With four fewer cautions than 2005, the 2022 race took just 44 seconds less to complete.

The field for the 1960 race included 60 cars. Only 18 of those cars (30%) crossed the finish line.

NASCAR disqualified six drivers for making illegal entrances to pit road. The reasons for the remaining 36 DNFs reads like an inventory of car parts, from “A-frame” to “valve.”

The number of cars failing to finish the race decreased significantly over the years. In the 1960s and early 1970s, it was not uncommon for 50-70% of the field to drop out of the race before its end. As the graph below shows, the DNF rate is now in the range of 10-30%.

Last year — the first year of the Next Gen car — had an abnormally high 46% DNF rate. That doesn’t signify a problem with car reliability.

Quite the contrary, in fact.

Racecar evolution has changed the nature of NASCAR’s longest race. The car have become so reliable that