Vittoria's Corsa CX is easily one of the most popular tubulars for pro racers, so how was the Italian brand supposed to make it better' It was no small challenge, but Vittoria stepped up to the plate, adding an even faster rolling rubber compound, and calling it the Corsa SL Tubular Tire. And like the CX, you'll find a buttery smooth 320 TPI cotton casing for fast rolling and light weight. So, when you need to go fast and you're done making excuses, this is your tire. The Corsa SL builds on the heritage of Vittoria's perennial favorite, the Corsa CX. And while the CX is a longstanding favorite of both pros and amateurs alike, the SL employs a faster rolling compound down the centerline, making this the fastest rolling tire that Vittoria offers. As with the CX, the SL employs a dual compound tread, which balances the harder centerline with softer shoulders in order to boost grip. They're not quite as grippy as the CX, but the SL still provides plenty of traction for leaning into turns at high speeds without any reason to hesitate. And now that we have your attention, let's dig into the SL's construction. Vittoria gave this tire a 320TPI casing composition, meaning that the sidewalls are comprised of 320 threads per inch. And if you're wondering why there are 'threads,' this is because the Corsa SL is a cotton tire. But, don't think that this decreases durability. In fact, Vittoria used a corespun, or 'polycore,' technique for the casing's construction. Essentially, this means that the casing fibers are made by twisting staple cotton fibers around a central filament core, creating one yarn from multiple fibers. As a result, the material is between 40 and 50% stronger than typically spun materials, while retaining a similar, if not lower, overall weight. Additionally, the 320TPI cotton casing provides the ideal stiffness to weight ratio for the SL. By this, we mean that the tire's weight hovers around 245 grams, depending on width, while still retaining a perfect ...