Continental Grand Prix 4000 Tubular: The all new Continental Grand Prix 4000 Tubular may be missing the aura of Continental's long standing tubular champion, the Competition, but it's still enticing professional cyclists with it's impeccable performance. A seamless - that's right seamless! - casing design improves rim seating, uniformity and rolling resistance. The casing is made from 4 plies of Nylon for a smooth rolling 240 tpi. The GP 4000 tubular is the only one of Continental's tires to have a seamless casing or 4 plies. This means the tire rides incredibly smoothly and also has class leading flat protection. Add Continental's Vectran breaker and Black Chili compound, and you've got yourself a real race winner.