By Jerry Jordan, Editor
SPARTA, Ky. – After decades of using 15-inch diameter tires, NASCAR and Goodyear definitely will increase tire size diameter – probably to 18-inches – beginning in 2021 when the new Generation 7 Cup Series racecar is put into use, Kickin’ the Tires has confirmed.
“It is not just a tire change, it is the overall Gen 7 package that everybody is working on for 2021,” said Greg Stucker, Goodyear’s Director of Racing. “Part of the whole idea is to try to update the cars somewhat, make it a little bit more relevant to what you see on the street these days. So, I think there will be probably some more differentiation among manufacturers, the car itself will be totally different from a performance perspective.
And one of the things we are looking at is to go with a larger diameter tire, a larger wheel diameter. We have been running 15-inch (tires) here in NASCAR for a lot of years now. If you look at cars on the street, you don’t see too many 15-inch wheel diameters anymore. So, we are looking at larger wheel diameters and our target is 18-inch.”
Stucker said Goodyear and NASCAR had built and tested tires and wheels with a 17-inch diameter a few years ago but after collaboration with the Ford, Chevrolet and Toyota they landed on the 18-inch diameter as the most logical choice going forward. It’s a change that is being centered around the not so easy task of redesigning the entire car used in the Cup Series and will bring the tire more in line with what is seen on production model vehicles.
“It will present a lot of opportunities from a performance standpoint but also present some challenges from a performances standpoint, also. It will be a challenge,” Stucker said. “The biggest thing is to try and tune it to the chassis itself. If we go to a larger wheel diameter, then typically we’ll go to a shorter profile, so the sidewall of the tire won’t be quite as tall. We will probably, also, add some width to the tire, so we will go with a little bit wider wheel, a little bit wider tire. And, again, try to tune it to the characteristics of the chassis.”
Stucker explained there is a lot still to determine on exactly how it will affect racing on the track but with a wider tire, there will be an increased contact patch between the tire and the track. Currently, the contact patch is about half the size of a sheet of copy paper. Any increase would give drivers more grip but, according to Stucker, it won’t necessarily increase heat build-up in the tire as the tire compound has yet to be finalized and would change from track-to-track like it does now.
A spokesperson for NASCAR stopped short of giving specifics other than to confirm the work being done, “Indeed, there is development work underway on an 18” set-up.”
Stucker said it is good that the entire sport is working together to make the racecar the best it possibly can be.
“You can’t say a wider tire is going to be better than a narrower tire,” Stucker said. “We’ll have to tune construction, we’ll have to tune compounds for a wider tire. All those different things will come into play. So, the goal will be to make sure we hit the sweet spot on every racetrack that we run. It will just be a process to work through and make sure we get everything tuned accordingly.”
And the process isn’t easy. Stucker said there is not a racing series out there that runs an 18-inch wheel diameter on a heavy stock car, like the Cup Series. One of the issues is things in NASCAR have been done the same way for years and the coming changes are going to be completely different.
Stucker said they aren’t sure where the price-point would come in for the new tires but he knows it can’t be a radical change because the overall goal is to save teams money and make the racing even better. Currently, a set of four tires is reported to cost teams $2,200. He again stressed the collaboration efforts.
“It’s a challenge,” he said. “These are still very heavy cars running on oval tracks where the loads are very high and very consistent. Nobody does that. So, it’s a challenge but we have a lot of history and we have a lot of great people in the garage that we work with to work on the package, so it is not just us it is everybody working together to get it right.
“It will be, in a lot of ways, a real shift from a design perspective and it’s going to be a very interesting project. I think it is extremely exciting. You know, from an engineering perspective, it’s exciting. It creates a lot of different opportunities we don’t have today from a performance perspective. And I think the relevance to the cars you see on the street is an important piece.”
There is no immediate plan to change from the current 15-inch diameter tire size in the Camping World Truck Series or the NASCAR Xfinity Series, Stucker said.
I’m just going to throw this out there. It’s wild speculation. This move to larger wheels, wider tires…and Dodge building new wide body Chargers and Hellcats. Related? Is FCA coming back to NASCAR or is it all coincidence?
Do we know the suppliers yet?
Basset and Aero dont even sell aluminum wheels.
A earlier report said the wheels for the development car are from BBS.
Plenty of “heavy” racecars are using alloy wheels – weight of Gen7 car has not even been announced yet, so it’s no doubt something that is part of the process. An 18″ steel wheel gets VERY heavy, but time will tell whether NASCAR works with current suppliers to come up with suitable 18″ wheels or decides to use aluminum.