The MTB headset rotates the fork tube in the frame's tube, it's a key part of steering. It is positioned between the fork, the frame and the stem.
Constitution of a MTB headset:
A MTB headset consists of a stopper assembled on the fork tube, cups assembled in the MTB frame, two bearings, an upper stopper, spacers, a stem cup and a star fixed in the fork tube.
The assembly of a MTB headset requires an Allen key set and an extractor for cups and a mounting tool in the case of a headset provided with external cups and a tube for the assembly of the lower stop. A workshop stand is also necessary in order to fix the frame during disassembly. For a headset screwed onto the fork tube, two flat keys will also be required.
1. MTB headset standard headset (stem attached to the fork tube)
Loosen the fixing screws of the stem on the fork tube