Aged to perfection: How NASCAR measures track surfaces

When food connoisseurs discuss fine wines, meats and cheeses, they will use the phrase “aged to perfection” to indicate the very best choices. With NASCAR drivers, the same can be said to describe a race track that has gained some character in its surface over the years, a condition that typically heightens the overall racing experience.

In such situations, searching for the right groove and controlling a sliding car are challenges drivers look forward to trying to master. Meanwhile, finding the right tire combination and strategies as tire wear comes into play are things to which Goodyear and the teams pay close attention.

Atlanta Motor Speedway is a favorite among drivers because its track has been aged to perfection, and it usually means exciting racing for the fans, too. And with a tripleheader in the NASCAR national series set for Atlanta this weekend, it’s the perfect time to discuss how NASCAR measures the surface texture of the tracks that host its events.

Joining us to help explain the procedure is David Groseclose, the director of tire systems and unified testing at the NASCAR R&D Center in Concord, North Carolina. A tire engineer for much of his professional career, Groseclose’s Twitter handle is appropriately @nascartireguy.

Groseclose is part of a team that travels to NASCAR-sanctioned tracks for tire tests, and during that time they also measure the track surface. He says their system includes checks at eight points around the track. Richmond Raceway was the example Groseclose shared with us, and there the team scanned for three-dimensional images on the frontstretch, the backstretch, in each of the four corners and at both apexes of the corners.

At each of those eight spots, three different grooves are measured, six images are taken per groove to represent the high line, the low line and the line in the middle — for a total of 144 images from the spots shown in the diagram:

Then once those images are collected, NASCAR measures in micrometers from the highest peaks in the surface to the lowest valleys. These differences are very subtle to the naked eye, but on the 3-D images on computers, an exact number is calculated for each track.

NASCAR collects the information together on a graph (below) where it’s easy to see where tracks fall on a continuum of smoothest to roughest. The lower the variance, the smoother the track, and thus the lower the number. You will see the concrete tracks to the left or the lower end in surface variance (as would be expected) and some of the aged asphalt surfaces to the right. 

The smoother the track, and thus the lower the number in average surface texture..Then NASCAR gets this information out to the tracks so it can be part of their decision-making process on when to resurface a track. The information also goes to Goodyear, the sport’s official tire provider, to aid in determining the right tire combination for each track.

But for fans who have ever wanted to put context behind whether a track is smooth, rough, or in the middle, it’s fascinating to look at the numbers, and it should be celebrated that each track surface has its own special characteristics and feel for the drivers. To use a different sport’s analogy, it’s like reveling in the differences in stadiums in the major leagues. Whether you prefer Fenway Park with its Green Monster protecting left field or Yankee Stadium with its short porch to right field, the differences are part of what make the game great, and the athletes that make the best adjustments to the changing landscape put themselves in a better spot for success.

Same for NASCAR and its tracks. The drivers and teams that do their homework will be the ones fighting for the win at the finish. Now when you hear the competitors discussing the adjustments they are making, you will know what goes behind those decisions.

3D Image for Michigan International Speedway

3D Image for Atlanta Motor Speedway