Its no surprise that more and more riders are seeing the benefits of aero tires. Nor is it a surprise that World Champion triathletes like Andy Potts and Michellie Jones are winning marquee races on the Zipp Tangente. After all, your tires have the highest airspeed of any part of your bike and the front tire is your machines leading edge. To cut through the wind, we've used our patented ABLC dimples to mitigate the "un-aero-ness" of a round shape at the wheel's leading edge. It took us 14 months and 2 trips to the wind tunnel to get it right, and the 21mm version of Tangente saves up to 9 seconds over 40km compared to a traditional file tread pattern. No other 23mm tire can touch the Tangente at that width, even when paired with a fully toroidal Zipp rim. But the Tangente is not just a delicate special event tire. Thanks to our partnership with Vittoria, the Tangente sports a durable yet supple 290tpi casing. Because the dimpled pattern resists cracking so well, we're able to use an exclusive an extra-light rubber compound for low rolling resistance and high cornering grip in wet and dry conditions. 21mm or 23mm widths. Average weight 245g, /- 10g. 38mm, overall length, approximately 34mm functional length. Includes tire pressure chart to optimize rolling resistance by rider weight and front/rear use.