The share of the U.S. original equipment and replacement tire markets held by high-performance tires — defined as H-rated and higher — has risen for eight straight years, according to U.S. Tire Manufacturers Association (USTMA) data, to nearly 56 and 45 percent, respectively.

A closer inspection of the data, however, shows the share held by V- and Z-rated tires have plateaued at OE at roughly 20 percent but continue to grow steadily in the replacement market, topping the 20-percent mark for the first time in 2017.

One explanation for this is the industry’s shift to SUVs and CUVs and away from traditional performance-oriented coupes and sedans. In fact, the V/Z-rated share hit 20 percent in 2013, then dipped under that plateau in 2014-16 before rebounding slightly last year.

It should be noted USTMA data refer only to shipments going to the global carmakers’ North American assembly plants. Vehicles imported from outside North America — which accounted for 23 percent of U.S. car sales last year — are not included in the numbers.

Aftermarket shipments in the U.S. of tires H-rated and higher rose 9.1 percent last year to 92 million units, a volume that represents 44 percent of all aftermarket shipments, up from 41 percent in 2016.

Viewed more closely, aftermarket shipments of H-rated tires rose 11.7 percent to 48.8 million units; V-rated tires rose 8.4 percent to 25.8 million units, and Z-rated were up 3.6 percent to 17.4 million units.

The share of the OE segment held by performance tires jumped 5 points last year vs. 2016 to 55.8 percent, USTMA data reveal, even though shipments to OE customers slipped 4.1 percent to 25.2 million units. The share rose because overall shipments of OE passenger tires to North American light vehicle producers fell, even more, 6.9 percent, reflecting a drop in production in 2017 in North America of cars, SUVs, light trucks, etc. to 17.2 million units.

The shift at OE is also reflected in the breakdown of OE tire sizes, where the 10 most popular sizes are now all 17, 18, or 20-inch rim diameter sizes. The replacement market lags OE in this regard, with no 18-inch sizes and two 15-inch sizes — 195/65R15 and 195/60R15 — still among the 10 most prevalent sizes, USTMA data reveal.