MTB Headsets

What is an MTB headset and what is its main purpose?

The headset supports the fork steerer inside the frame's head tube. It ensures that the handlebars turn smoothly and without play. In the MTB sector, sealed industrial bearings are standard to keep out dirt and water.

What types are there (S.H.I.S.)?

To organize the chaos of sizes, there is the S.H.I.S. (Standardized Headset Identification System). It describes the bearing position:

IS (Integrated)

The bearings drop directly into the frame. There are no cups to press in. Very common on modern Dirt Jump frames (e.g., IS42/IS52).

ZS (Zero Stack / Semi-Integrated)

The bearings sit inside cups that are pressed into the frame but sit almost flush with the head tube.

EC (External Cup)

The bearing cups sit visibly outside the frame. Often found on older frames or used to raise the front end.

What does Tapered mean?

Modern MTB forks usually have a Tapered steerer (conical: 1.5 inch bottom, 1 1/8 inch top). Your headset must match: The bottom bearing is larger than the top one.

Tip: With a special reducer race, you can often run an old 1 1/8 inch fork in a modern Tapered frame.

How do I install a headset?

1. Pressing in: For ZS and EC, the cups must be pressed straight into the frame using a press tool. (For IS, skip this – simply drop the bearings in).
2. Crown Race: Install the crown race onto the fork steerer.
3. Assembly: Grease everything well, insert the fork, place the upper compression ring and top cap cover.
4. Adjustment: Install the stem, tighten the top cap bolt until play is eliminated, then tighten the stem clamp bolts.

What do the specifications mean?