Home » headsets » Tapered Headsets » p504a-1 TAPERED HEADSETS P504A-1 IS42/28.6 | IS52/40 Alloy Sealed Bearings 1-1/8″ to 1.5″ Tapered Head Tube & Steerer Top Nut: 1-1/8″ Bearing O.D.: 41.8/52 Crown Cone: 39.8 Height: 5.4 Technical Diagram