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 (45×45 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 (45×45 degree)
• 48mm OD flush top cover.
• Split plastic compression ring.
• Split 1.5″ alloy crown race.
• 2018 – 2025 Chisel / 2018 – 2019 Epic Alloy