NASCAR race cars haven’t been “stock” since the late-80s, but they attempt to stay relevant to Joe Everyman and his daily driver. Under the skin, whether it’s a Dodge Charger, Toyota Camry, Chevy Impala, or any other model, all NASCAR vehicles are practically identical. Still, racing technology often makes its way back to our daily drivers, for better power, stability, fuel economy, handling, safety, you name it. Transferring power to the asphalt is where Goodyear Tires has made its mark, critical equipment that can make or break a racer’s chances at victory.

Since 1969, Goodyear tires shod every Cup Series championship vehicle. In 1997, Goodyear became NASCAR’s exclusive tire provider, delivering some 120,000 tires to NASCAR events every year. Since then, yellow-lettered Goodyear Eagle Radial Race Tires have shod 15-inch steel wheels, usually provided by AERO or Bassett Racing. Coming in at 28 inches in diameter and 11.5 inches wide, Goodyear Eagle Radial Race Tires cost upwards of $400 each and tend to last less than 200 miles, after which they’re returned to Goodyear for further testing and analysis.

Interestingly, while production vehicles have moved on from 15-inch wheels in recent years, NASCAR is only just catching up. Today, it’s not uncommon to see even economy cars with 16- or 17-inch wheels, and a great many cars, trucks, and SUVs are equipped with 18-, 19-, 20-, even 21-inch wheels straight from the factory.

To get NASCAR “stock” vehicles up-to-date with modern big-wheel trends, Generation 7 Cup Series, set to start in the 2021 racing season, will get a bigger set of wheels. A few years ago, Goodyear, NASCAR, and a few NASCAR major manufacturers did some testing with a 17-inch wheel, but it didn’t result in any immediate changes. Goodyear Tire and Rubber Company Director of Racing Greg Stucker says, after talks with NASCAR’s major manufacturers, the new wheels will be 18 inches in diameter.

Practically everything in the vehicle, from the suspension and steering system to weight distribution and cooling, revolves around keeping the tires at maximum performance. To start with, it’s unlikely Goodyear will keep the same sidewall height, which means the new lower-profile tire will deflect less and damp less. Air-pressure tuning will likely be less effective, and heating might become more of an issue. It’s good to note the new NASCAR 18-inch tire specifications are far from finalized and we’re bound to see future updates as teams put them through their paces.

Among many other changes to the Gen 7 Cup Series race cars, such as new body styling, downforce specifications, and new engine specifications, making the change to an 18-inch wheel is arguably one of the most critical. Drivers will have to relearn traction and pit managers might be in store for some surprises. At the very least, making the chance to 18-inch tires in NASCAR’s 2021 racing season will give Goodyear a lot more data to work with as it analyzes thousands of used tires every week.