Repair guides › Cockpit
Adjust headset play
The bearings that let the fork turn in the head tube. Two bearings (top and bottom) sit in cups pressed into the head tube. The stem clamps the steerer; the top cap bolt pulls the fork up to take out play (preload), then the stem bolts lock everything. Budget bikes often use caged ball bearings (EC sizing).
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Tools
- Ball-end hex key set (1.5–10 mm): Park Tool HXS-1.2 Professional L-Shaped Hex Set ($$)
- 1/4" click torque wrench (about 2–17 Nm) + bits: Pro Bike Tool 1/4 inch drive click torque wrench set (2.2–16.9 Nm) ($$)
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Steps
- Hold the front brake and rock the bike forward and back with a hand wrapped around the top headset cup. A clunk means play.
- Loosen the two stem pinch bolts (the ones clamping the steerer) a couple of turns.
- Tighten the top cap bolt 1/8 turn at a time; snug the stem bolts and re-check for play after each. Stop as soon as the clunk is gone, then loosen the stem bolts again to adjust further.
- Lift the front wheel and turn the bars: they should swing freely with no tight spot. If tight, back the top cap off slightly.
- Line the stem up with the front wheel (stand over the bike and sight down).
- Tighten the stem pinch bolts alternately to spec. The top cap does not hold anything once the stem is tight.
Torque
| Fastener | Torque |
|---|---|
| Top cap | snug only (~1–2 Nm), sets preload |
| Stem steerer bolts | 5–6 Nm (check stem marking) |
| Carbon steerer | usually 5 Nm max, with carbon assembly paste |
Diagram
Taken apart, in order, side viewHead tube and stem
Signs it needs doing
- Clunk felt through the bars when you hold the front brake and rock the bike
- Steering feels notchy or stuck straight ahead (worn bearings)
- Bars feel tight when turning (too much preload)