Bottom Assy AER IS 47mm 1.25" ALLOY BEARING & Crown Race IS47/33 Black (BAA1045)

Cane Creek Headset Bottom Assy AER IS 47mm 1.25" ALLOY BEARING & Crown Race IS47/33 Black BAA1045 LIGHT AS AER Long recognized as the world’s lightest headset, the new AER now offers a hybrid steel and aluminum bearing that provides even greater durability and a 40% weight savings over comparable models. Strategic machining and precision contours provide an optimal balance between weight and strength. The new AER headset is now an ideal headset choice for road and mountain bike applications - a high quality durable headset at the lightest weight possible. FEATURES CUPS AND COVERS 7075 T-6 Aluminum CROWN RACE Aluminum crown race with integrated low-friction seal COMPRESSION RING Cup-in compression ring TOP BEARING 41mm or 41.8mm Cane Creek Aluminum Bearing LOWER BEARING 47 and 52mm Cane Creek Aluminum Bearing AVAILABLE FITS TOP ASSEMBLIES IS41/28.6/H9 9mm Cover (Integrated 1-1/8” Standard) IS42/28.6/H9 9mm Cover (Integrated 1-1/8” Italian Standard) ZS44/28.6/H8 8mm Cover (ZeroStack 1-1/8” Standard) BOTTOM ASSEMBLIES IS52/40 (Integrated 1-1/2” Tapered) ZS56/40 (ZeroStack 1-1/2” Tapered) EC44/40 (External Cup 1-1/2” Tapered) EC44/33 (External Cup 1-1/4" Tapered) VIA CONVERSION CROWN RACE IS47/33 (Integrated 1-1/4" Tapered)