A complete 440C stainless steel drop-in headset for integrated IS41/IS52 head tubes, made as a direct-fit replacement for the bearings your frame came with.

Highlights

• Fits integrated head tubes with 41mm upper / 52mm lower IDs and tapered 1-1/8 to 1-1/2 steerers
• Upper and lower bearings with 36°/45° chamfers, plus a 36° crown race and compression ring
• 440C stainless steel balls and races, dual-lip seals top and bottom
• 90% fill of high-pressure waterproof grease
• Hidden bolt top cap preload adjuster and HD-120 upper spacer included
• 7.5mm total stack

Built from 440C stainless

Enduro stainless headsets use 440C balls and races, dual-lip seals top and bottom, and a 90% fill of high-pressure waterproof grease. Enduro says they are guaranteed for as long as you own the bike.

What's in the kit

Upper bearing ACB 3645 SS, lower bearing ACB 6808 SS, upper bearing cap, hidden bolt top cap preload adjuster, 36° crown race, compression ring and an HD-120 upper bearing spacer.

The bearings

The upper 1-1/8 bearing (ACB 3645 SS, also known as 27287-1046-004, HSS0130K, TH-873E and MR-122) is 30.2mm ID x 41mm OD x 6.5mm. The lower 1-1/2 bearing (ACB 6808 SS, also known as HD 1404K, BAA0006K, MR-127, MR-196, MH-P25K, BAA1132 and TH MR019) is 40mm ID x 52mm OD x 6.5mm.

Compatibility & fit

Fits frames with integrated head tubes taking 41mm OD upper and 52mm OD lower bearings with 36°/45° chamfers, and forks with a tapered 1-1/8 to 1-1/2 steerer. Enduro designs it as a direct-fit replacement. If you need extra clearance between the fork crown or bearing cap and the head tube, use the included HD-120 upper spacer; a WA-36 1x150 lower spacer is sold separately. Total stack is 7.5mm (6.5mm upper, 1mm lower). Headset installation is a separate workshop service, and our workshop has the press tools to fit it for you.