If you ride a bike it’s almost inevitable that, at some point, your headset will become loose and require tightening. Accordingly, home mechanics often loosen them to remove or replace components too.
This brief article explains what a headset is and how to tighten it.
What is a headset?
A headset is a component which attaches your forks to your frame and allows your bars to rotate.
The basic components of a headset are:
- a top cap that compresses and draws all the headset parts, stem + spacers together and holds them in place. Basically, it sits on top of the stem at the top of the fork steerer tube
- a fork steerer bung or star nut – fitted into the fork tube for the top cap to screw into
- a headset upper cap that sits on top of the headtube and under the stem. This keeps the upper bearing in place.
- an upper bearing which may/may not sit in or on a frame-fitted race depending on the frame type
- a lower bearing which may/may not sit on a fitted crown race depending on the frame type
NB: Most modern frames are now designed so fitted bearing races are not required, headset bearings simply fit directly into the frame head tube
How to check for a loose headset
Checking for play in your headset is easy enough. Simply apply your front brake, wrap your hand around the upper part of the headtube and the headset upper cap and finally rock the bike backwards and forwards. Conversely, if it is loose, you will feel the components and frame move independently.
Further Reading
Why do I need a tight headset?
A loose headset can compromise your braking and handling. Furthermore, it can also cause damage if it’s too loose for too long. When setup correctly you should be able to turn your bars freely left and right. When you apply your brakes you should be confident they work as soon as they begin to bite without any play.
Assembly of a headset
Assembling a headset into a frame is relatively simple (assuming the steerer has been cut to the correct length)
- Firstly, the lower bearing (+ optional crown race) is greased and fitted onto the bottom of the fork steerer/crown
- The fork is fed up through the headtube. The lower race is slotted into the bottom of the head tube (or frame fitted race)
- The upper bearing is greased and seated into a fitted race or directly into the frame headtube.
- The headset upper cap + a compression ring are seated on top of the upper bearing
- Any spacers required under the stem are fitted
- The stem is fitted (but not tightened!)
- Any spacers required above the stem are fitted
- Finally, the stem top cap is fitted and tightened to remove any play
NB The stem top cap is screwed into either a fitted star nut (alloy forks) or a steerer bung (carbon forks) inside the fork steerer tube.
Tightening a loose headset
A loose headset can be simply remedied.
- Firstly, undo the stem bolts that clamp the stem to the fork steerer
- Tighten the top cap on top of the stem to compress the headset components and stem to remove any play
- Finally, tighten up the stem bolts to their recommended torque rating (often displayed on the stem in Nm)
If the top cap is tight and there is still play, it can be a couple of common reasons
- The fork steerer may be too long. Cut the steerer to the correct length or add a spacer above or below the stem.
- The fork steerer bung may have slipped. Simply remove, refit and tighten correctly
Loosening a headset
If your headset is setup correctly, of course, you may want to loosen it to remove components to clean or replace them.
- Firstly, undo the top cap and remove it
- Undo the stem bolts that clamp the stem to the fork steerer
- You can now disassemble your headset, stem and forks
NB If your front wheel is off the ground in a workstand, for example, be aware when the headset and stem are undone the fork may drop out of the frame if not supported
