Sealed Bearings

Inner x Outer x Depth (mm): 35 x 47 x 7
Inch Dia: 1 - 1 / 4”
Angle / Chamfer (Deg): 36 / 45
Material: Chrome Steel 100Cr6 (Race & Balls)

Inner x Outer x Depth (mm): 35 x 47 x 8
Inch Dia: 1 - 1 / 4”
Angle / Chamfer (Deg): 45 / 45
Material: Chrome Steel 100Cr6 (Race & Balls)

AI52/Ai52 Upper Headset Bearing, Note the lower bearing is our part ref 'P16'

Inner x Outer x Depth (mm): 42 x 52 x 7
Inch Dia: 1 - 1 / 2”
Angle / Chamfer (Deg): 45 / 45
Note: Same fit as Acros AC4252

Believed to be used on Venge frame 2016 Onwards. If in any doubt, please check dimensions of current bearing for comparison.
Note, older Venge frame upto 2015, see part number MH-P08F for upper bearing

Inner x Outer x Depth (mm): 35 x 45.3 x 7.3
Inch Dia: 1 - 1 / 4”
Angle / Chamfer (Deg): 45 / 45

Used on Roubaix, Ruby and Diverge 2017 Models onwards using Future Shock Headset (equivalent to Specialized part refs: S182500006 & S172500014)

Inner x Outer x Depth (mm): 36.8 x 45.8 x 6.5

Angle / Chamfer (Deg): 45/45

Lower Bearing for Scott Foil Addict
Upper Bearing for Scott Foil 2016 Onwards (see ACB519H8 for lower bearing Foil 2016 onwards)

Inner x Outer x Depth (mm): 34.1 x 46 x 7
Inch Dia: 1 - 1 / 4”
Angle / Chamfer (Deg): 45 / 45
Material: Chrome Steel 100Cr6 (Race & Balls)

Believed to be used on Venge frame 2016 Onwards. If in any doubt, please check dimensions of current bearing for comparison.
Note, older Venge frame upto 2015, see part number MH-P21 for lower bearing

Inner x Outer x Depth (mm): 40.5 x 49.5 x 6.5
Inch Dia: 1 - 1 / 2”
Angle / Chamfer (Deg): 45 / 45

NOTE, The Planet X Nanolight, Ribble R872, Ribble Stealth and De-Rosa R839 have used this lower bearing (but please check your lower bearing size to make sure it is the 51.5mm as we haven't had it confirmed that all these models ALWAYS used this headset/bearing size for the life of this model range)

Inner x Outer x Depth (mm): 40 x 51.5 x 7
Inch Dia: 1 - 1 / 2”
Angle / Chamfer (Deg): 45 / 45

This is same as ACB518K, but not so popular - has 45 deg for both chamfers 

Inner x Outer x Depth (mm): 40 x 51.8 x 8
Inch Dia: 1 - 1 / 2”
Angle / Chamfer (Deg): 45 / 45
Note: Equivalent Part ref PT-R425, P28

RITCHEY FIT

Inner x Outer x Depth (mm): 40 x 51.9 x 7
Inch Dia: 1 - 1 / 2”
Angle / Chamfer (Deg): 45 / 45
Material: Chrome Steel 100Cr6 (Race & Balls)