BBB - Semi-integratedBBB SEMI INTEGRATED BHP 51 The Integrated headset keeps your handlebar turning nice and smooth to make sure you can take every corner as tight as you want, and the durable sealed bearings makes sure you can keep doing that for a long time! BHP 51: Zero Stack (ZS) Semi Integrated SHIS Lower ZS44 30 SHIS Upper ZS44 28. 6 Sealed CrMO Bearings 1 1 8" (41. 0mm) Cone Spacer Diameter 50mm Cone Spacer height 8mm Crown race included Fork Size: 1 1 8" BHP 53