The Vector R Zipp Fitment Series Tire comes in two builds tuned to two different Zipp wheels. The NSW fitment targets the Zipp 353 NSW with a 150tpi casing built for lightweight climbing, backed by an R:Shield breaker for added protection. The SW fitment targets the Zipp 303 Firecrest in both 700x30 and 700x35, with a 120tpi casing built for volume and durability across mixed road surfaces. Both share the same Dynamic:UHP compound for efficient rolling underneath that fitment-specific casing work. What Our Gearhead(R) Experts Are Saying:"I felt the NSW disappear underneath me on a long climb, then swapped to the SW build for a rough descent and never second-guessed the traction. Two tires, two jobs, both done right."