SIZING: Castelli products have a close-to-the-body fit to maximize aerodynamics and performance. For a less compressive feel, or if your measurements fall between sizes, we recommend that you size up. IDEAL FOR: Cyclists tackling long training rides, century events, or endurance races who demand all-day comfort, moisture control, and reliable muscle support. Temperature: 15°C - 35°C / 59°F - 95°F. Weight: 203 g. Predecessor: Men’s Endurance 3 Bibshort. PREMIUM ENDURANCE PERFORMANCE: Endurance Evolution fabric delivers firm muscle support with high-stretch comfort, keeping you drier and fresher through long hours in the saddle. Ideal for variable weather conditions. Anatomic panel construction provides a precise, on-bike fit that moves with you, while GIRO3 leg grippers lie flat for a secure, smooth hold without constriction. MAXIMUM RIDING COMFORT: Progetto X2 Air Seamless seat pad combines advanced cushioning, breathability, and pressure relief for unparalleled long-distance comfort and improved airflow. ENHANCED COOLING & SUPPORT: Mesh bib straps and back panels enhance ventilation, keeping your core cool and your fit stable even during the hottest or longest summer rides. What Our Gearhead Experts Are Saying:"I reach for the Endurance 4 Bib Short when I know I'm in for a long ride. The Progetto X2 chamois is the most comfortable I've ever used—it’s plush without feeling bulky. The mesh uppers breathe well and stay put, and the compressive fit gives my legs a nice boost over long climbs or tempo efforts."We count on the Endurance 4 Bib Short for long rides that push past comfort zones and into new mileage records. Castelli’s premium Progetto X2 Air Seamless chamois is the star of the show, offering the kind of all-day support that makes century rides more enjoyable and recovery a little easier. The bibs fit close and move naturally, giving us a performance edge without sacrificing comfort. The Endurance Evolution fabric delivers compressive muscle support while managing moisture efficiently, so we stay dry and supported from first pedal stroke to final climb. Mesh straps and back panel keep airflow high, and GIRO3 leg grippers hold the cuffs in place without digging in. When we want to go far—and fast—these are the bibs we trust.