NASCAR: Here’s the Biggest Difference Between Next Gen and Older Cars

by Caitlin Berard
(Allen J. Schaben / Los Angeles Times via Getty Images)

In 2021, NASCAR unveiled the seventh evolution of its iconic vehicles, the Next Gen stock car, which were rolled out at the start of the 2022 season. The new car came with a wide variety of differences from that of the sixth generation, but NASCAR fans immediately noticed one distinct change with the Next Gen car – its lack of lug nuts.

Rather than the traditional five lug nuts, each wheel on the Next Gen car is equipped with a single, center-locking lug nut, which NASCAR is calling the “mono lug.”

The reduction in the number of lug nuts came with a drastic increase in the size of the crucial part. Though the Xfinity and Truck Series vehicles still use the old 1-inch lug nuts, the Cup Series now uses a much larger lug nut, several inches in diameter.

Now, the new mono lug didn’t make the execution of pit stops wildly different. Because the larger single lug requires more torque to fasten the wheel correctly, pit crews can’t change tires in a fifth of the time. However, the mono lug system did come with one major change – there’s no longer a need for glue on the wheels.

“They’ll use the same lug the entire time,” said John Probst, NASCAR Senior Vice President of Innovation and Racing Development. “So the concept of gluing lug nuts to tires goes away, which creates some efficiencies for us. There’s times when we have to open up the garage or pit road early on race day for no other reason than for the race teams to glue up 11 sets of tires. They can just use the wheels as they are without being glued.”

Other Differences in the Next Gen Car

One of the other major differences between the Next Gen and sixth-generation stock car is the increase in wheel size. Rather than the 15-inch steel rims of the sixth generation, Next Gen cars sport 18-inch aluminum rims.

This is an upgrade from the previous model, as the aluminum wheels reduce the cars’ unsprung mass. Lightweight rims mean better traction across bumps and other imperfections in the track. Also, let’s be honest, the modern rims just look cooler.

Additionally, because the cars have larger rims and smaller centerlock hubs, they have much more room for brakes. The Next Gen cars boast a 25% increase in stopping power. Vice President of Hendrick Motorsports, Chas Knaus, called the new brake system “really great”.

The seven-time NASCAR Cup winning crew chief added that the larger rotors make a world of difference. They allow “the driver to slow the car down without generating a lot of heat”.