Challenge's Pista Open Tubulars rule the velodrome. The casings are crafted with their top-quality, 320tpi CoreSpun cotton. It makes for a supple, strong, and light tire that flies across the boards. With the high thread count, the 320 holds your line at any speed. Open tubular construction features many benefits of traditional tubular tires, but with the low maintenance and easy installation of a clincher tire.