UPDATE: Quotes from NASCAR Senior Vice President of Racing Innovation John Probst:
John Probst on the move to an 18" center lock aluminum wheel.
One of our main goals with the Next Gen car is to provide a vehicle that better replicates what our OEM partners sell in the showroom – both in looks and relevant technology. Moving to an 18" forged aluminum wheel helps do just that.
Once the decision was made to go that direction, we tested different lug nut options. With the loads on the larger wheels, we had to make sure that the wheel would remain securely fastened the car. The single lug, center lock design was the best way to accomplish this.
John Probst on how the new wheels will affect pit stops
The choreography of a pit stop won’t change. You’ll still have the same over-the-wall crew members you have today, and rules related to when they can enter the pit box are still in effect.
It will still be important for the tire changers to be quick off the wall to get to the far side of the car. Hand-eye coordination remains extremely important, you’re still trying to get the lug and tire on and off the car faster than 39 other teams. The overall way a pit stop looks will remain the same.
In terms of timing, the torque is higher on the single lug, which means they have to leave the gun on longer. In our testing, we’ve found that it takes approximately half a second to properly tighten this new lug. Today, a good tire changer can remove five lugs in about .8 seconds. So, while pit stops may be a touch quicker next year, it won’t be a significant difference.
— NASCAR —
ORIGINAL POST: NBC Sports’ Nate Ryan breaks the news that NASCAR will move to a single lug nut on the Next Gen car in 2021:
NASCAR will switch to a single lug nut for fastening its tire and wheel assemblies in Cup cars next season, ending decades of using a renowned five lug nut pattern.
An official told NBC Sports the move was driven by the new 18-inch aluminum wheels (3 inches bigger than the current wheel) that will be used with the NextGen car, which will make its debut with the 2021 season, and are intended to increase product relevance for manufacturers.
According to engineering analysis, NASCAR senior vice president of innovation John Probst said the durability of the new wheels decreases by 30 percent with five lug nuts.
Probst said most Cup teams are in favor of the move, which NASCAR hopes will allow teams to use wheels in multiple years (instead of multiple races with the current steel wheels).
Other notable elements from the move to a single lug nut:
-There will be no more postrace lug nut checks or lug nut penalties.
-Because the lug nut will be retained in the socket, the change from five lug nuts will end the practice of gluing lug nuts to the wheels, which will cut down on prerace preparation time.
-Teams should be replacing wheels less often because five lug nuts deliver more of a pounding than a single lug nut – particularly when they aren’t tight and the wheel wobbles.
-NASCAR has no plans to adjust pit crew or roster sizes.
See much more at NBC Sports.