Acros AZ-44BL Block Lock ZS44/28.6 Upper Headset

Item number: 40389

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Acros AZ-44BL Block Lock ZS44/28.6 Upper Headset - black/ZS44/28.6
Acros AZ-44BL Block Lock ZS44/28.6 Upper Headset - black/ZS44/28.6
  • 100 day return period
  • Online since 1998
  • Trusted Shop 0 / 5.00
Use: Designed for 1 1/8" upper head tube diameters combined with standard 1 1/8" or 1 1/8" - 1.5" tapered forks.


Application: Cross Country, City & Touring
Upper Cup: 1 1/8"
Steerer Tube: 1 1/8" , 1 1/8" - 1.5"
Design: zero stack (ZS)

Technical Information:

Material: aluminium 2000
Bearings: stainless steel angular contact cartridge bearings
Upper Insert Depth: 9 mm
Upper Stack Height: 12.5 mm
Upper Outer Diameter: 44 mm
Upper Inner Diameter: 28.6 mm
Seals: R3 (metal-reinforced rubber seal)

Standardized Headset Identification System (S.H.I.S.):

The Standardized Headset Identification System (S.H.I.S.) creates a common language for describing modern bicycle headsets. The system provides comprehensive and scalable headset fitment information in a standardized format; making it easy to communicate headset requirements based on frame and fork interfaces. The system addresses the critical interface dimensions required to fit a fork to a frame, as well as bearing location / cup type. To determine fit, four dimensions are needed: (1) stem-clamp diameter of fork, (2) crown-race seat diameter of fork, (3) head-tube top inside diameter, and (4) head-tube bottom inside diameter. Bearing location and cup-type are identified as (a) external cup (EC), (b) semi-integrated or zero stack (ZS), or (c) integrated (IS).


EC: Bearings contained within cups that are located outside of the frame (external cup).
ZS: Bearings contained within pressed-in cups where the cup and bearings rest inside the frame (zero stack).
IS: Bearings that fit directly into a bonded or machined interface that is integrated into the frame (integrated).

Use the AH-T DIY to press in your headset.

Manufacturer Part Numbers:

black: 51.02.605S
red: 51.04.605S


- 1 x Acros AZ-44BL Block Lock upper bearing cup, incl. stainless steel bearings
- 1 x clamp
- 1 x headset dust cap
- 1 x Ahead cap
- 1 x star nut with M6 x 30 bolt
- 1 x compression ring


  • black/ZS44/28.6: 81 g


in stock 2 to 7 days up to 10 days Out of stock inform me
  • red/ZS44/28.6
  • black/ZS44/28.6

Customer Reviews (3)


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Customer Reviews (3)


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by Christian W.  on 12.04.2019

zwar leider nicht bei BC gekauft aber ist in meinen Augen sogar besser als ChrisKing Steuersätze !

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by Paul V.  on 07.01.2017
verified purchase
3 of 3 customers found this review helpful.

1a Verarbeitung des Produkts und einwandfreie Montage und einstellung war gewährleistet. Die schlechte Bewertung wegen einer viel zu fest angezogenen Schraube kann ich nicht verstehen. Wie sagt man so schön: "Don´t be a fool and use a Torque-Tool"!
Nebenbei sei auch erwähnt dass der Zentrierring zwar aus Plastik ist, Acros aber mitgedacht hat einen Zweiten als Ersatz mit ins Päckchen zu packen.


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by Leon B.  on 20.03.2016
verified purchase

Does what it should do. Good quality.

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