Home » headsets » internal cable routing » c525a Semi-internal Cable Routing Headset Installation INTERNAL CABLE ROUTING HEADSET C525A IS52/28.6 I IS52/40 Alloy, Sealed Bearings 1-1/8″ to 1.5″ Tapered Steerer Top Nut: 1-1/8″ Bearing O.D.: 51.8 Crown Cone: 39.8 Height: 14 Weight: 138g Technical Diagram