The bicycle headset refers to the round parts on the top and bottom of the bicycle front tube (the round tube in front of the rack), usually called five-piece bowls (also divided into upper and lower bowls.)
Below I will introduce two representative headsets-fully hidden headsets and semi-hidden headsets)

Hidden headset

GH-542

Size: 1-1/4" to 1-1/2"
Finish: Silver, BK, AD
Material: Aluminum
Diameter: 31.8*41.8-52*39.8
S.HEIGHT: 9.5+1=10.5+1mm
Bearings: Sealed Cartridge(P27*P16)
Weight: 75g+75g

The first is that the bearing or loose beads (requiring a bead bowl) can be completely hidden in the inner diameter of the frame head tube, and the outer and inner diameters of the bearing type bearing can withstand the head tube and the rigid tube, and the head tube is preset with the frame of the bearing You can install a fully hidden wrist group. The fully hidden wrist set only has two bearings, and a set of Allen wrenches can be installed.

Semi-hidden headset

GH-230

Size: 1-1/4" to 1-1/2"
Finish: Silver, BK, AD
Material: Aluminum
Diameter: 31.8*44-56*33 or 39.8
S.HEIGHT: 10+5.3=15.3+1mm
Bearings: Sealed cartridge(P27*P16)
Weight: 140g+30g

How to install it correctly?

1. First, fix the frame on the maintenance frame, and check whether there are burrs or residual glue on the inner wall of the frame head tube, and simply clean it.
2. The headset is roughly divided into two parts: the upper gear group and the lower gear group. First, take out the bearings, the headset clearance ring, and the front fork bottom gear separately.
3. Then apply grease evenly on the outside of the upper and lower gears.
4. In order to ensure that the headset can be horizontally pressed into the head tube, the installation tool is very important. Please use the special static pressing tool for the headset to install. Avoid violent installation methods with hammers to avoid irreversible damage to the frame.
5. Put the upper and lower gears into the static pressing tool in turn.
6. Make sure that the upper and lower gears are kept in a horizontal position, and then slowly press them into the frame head tube.
7. After the press-in process is completed, carefully check whether the position between the upper and lower gears and the frame head tube is pressed in place. The upper and lower gears must be close to the head tube without leaving a gap.
8. After the headset is installed, you can install the bottom gear for the front fork. Before installing the bottom gear, apply grease to the fork base, and then put the bottom gear into the front fork with the inclined surface facing up and the plane facing down. Put in the sleeve and hit the bottom stop firmly until it is in place.
9. Finally, put some grease on the bearings of the headset and the bottom gear for lubrication and waterproofing. Finally, put the front fork into the frame and place the corresponding number of washers according to personal habits, and then tighten the stand screws.
10. After the headset is installed, the bearing position should be in a horizontal position, and the front fork rotation should be smooth and without resistance.

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