There's no denying that a ride on a great tubular tire is a wonderful experience, and if you're going to make the switch to tubulars, do yourself a favor and wrap some Challenge Strada Tubular Tires around your favorite hoops. For the casing of the Strada, Challenge used its handmade, highly puncture-resistant, and lightweight SuperPoly material featuring 300 threads per inch for a remarkably supple ride that you'll feel the first time out. On top of the casing, Challenge added a belt of corespun polyester, made by twisting fibers around a central filament core to create one yarn from multiple strands. As a result, the material is between 40 and 50% stronger than traditionally spun materials, yet it retains a similar, if not lower, overall weight. This layer is referred to as the Puncture Protection System, and it's specifically made from the tightly woven polyester material to preserve the casing's supple feel. The 25-millimeter-wide profile is then wrapped with the popular Paris Roubaix herringbone tread pattern, a design that continues to be one of Challenge's most versatile patterns for a variety of road surfaces when speed and grip reign supreme. The tread is applied using Challenge's proven hand-glued methods, which involve mounting and inflating the casing on a wheel, and only then does Challenge carefully glue on the tread layer. As a result, the tread isn't put under tension when you inflate the tire on your wheel, and that lack of tension leads to lower rolling-resistance, added grip, and increased comfort.