Complete Zero Stack press-fit headset for Chisel HT bikes. • Upper Cup: Zero Stack 44 (ZS44) press-fit cup for 1-1/8" bearing. • Upper Bearing: 1-1/8" - 41.8mm OD x 30.5mm ID x 6.5mm Thick (45x45 degree). • Lower Cup: Zero Stack 55.9 (ZS56) press-fit cup for 1.5" bearing. • Lower Bearing: 1.5" - 52mm OD x 40mm ID x 7mm Thick (45x45 degree) • 48mm OD flush top cover. • Split plastic compression ring. • Split 1.5" alloy crown race.
