The Tangent is Zipp's attempt at developing an "aero tire". They claim it's the first tire to be developed in a wind tunnel, to minimize the amount of aero-dynamic drag. The tire actually has Zipp's patented dimples. Zipp claims a remarkable savings of "1-3 watts, or up to 9 seconds over 40km". We dare not support such a dramatic claim, but we can tell you the Tangent has a nice ride quality. It's no coincidence that it happens to ride a lot like a Vittoria EVO CX Open Tubular (open clincher). With a 290tpi casing, the tire is very supply conforming nicely over bad road surfaces. Zipp uses an especially soft rubber, improving cornering ability and decreasing rolling resistance. The tire also includes a PSI chart to optimize PSI according to rider weight. We tend to pressurize based on rider weight, and road conditions, and the type of riding, so we're not sure how useful this chart is going to be to you.

21mm width in black
Weight: 230g