Continental GP4000 S II Tubular Road Tire. Continental's superb 4000 S II clincher tire has long been praised as having a near tubular like performance and ride quality, and now Continental has upped the ante by providing a tubular version of the 4000 S II for those seeking a perfect all around tire. The 4000 S II tubular utilizes Continental's renowned BlackChili compound to maximum effect. This tread compound not only reduces rolling resistance by 26%, but also provides 30% more grip when compared to silica compounds. Furthermore, the BlackChili compound provides an exceptional tread lifespan and unlike many multi compound tires ensures a constant ride from the first to last kilometer. Additional peace of mind is provided by the Vectran Breaker puncture resistant layer. Modeled after spider silk, Vectran is spun from the melted liquid polymer Vectra and processed further to a multi strand thread. The spider silk like Vectran possesses an enormous tear resistance at a very low weight so much so that it helps reduce punctures with no adverse effects on rolling resistance. Add in an amazing 240 TPI casing for a superbly supple ride and you've got all the ingredients necessary to leave the competition behind on race day.