Repair guides › Cockpit

Flip stem or move spacers (bar height)

Connects the handlebar to the fork steerer. Its length and angle set how far forward and how high the bars are. Two pinch bolts clamp the steerer; a faceplate (2 or 4 bolts) clamps the bar. Flipping the stem changes its angle (flipping a 7° stem raises or lowers the bar about 1 cm on a 50 mm stem, about 2 cm on a 90–100 mm stem). Moving spacers above or below it changes height.

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Tools

• Ball-end hex key set (1.5–10 mm): Park Tool HXS-1.2 Professional L-Shaped Hex Set ($$)
• 1/4" click torque wrench (about 2–17 Nm) + bits: Pro Bike Tool 1/4 inch drive click torque wrench set (2.2–16.9 Nm) ($$)
• Preset 5 Nm torque key: Prestacycle Pro TorqKeys 5 Nm T-handle ($$)

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Steps

1. Note your current bar height (floor to top of bar at the stem).
2. Remove the top cap. Keep the front wheel on the ground or hold the fork (once the stem is off, nothing stops the fork sliding out of the head tube). Loosen the steerer bolts and slide the stem off.
3. To raise the bar: move spacers from above the stem to below it, or flip the stem to point up.
4. To flip, remove the faceplate, rotate the stem 180°, refit the bar centered, tighten faceplate bolts evenly in a cross pattern so the gaps are equal top and bottom.
5. The top of the steerer must sit about 3 mm below the top of the stem (or of the top spacer) so the top cap can pull the stack down. If it is flush or sticks up, move a spacer from above the stem to below it. Carbon steerers: most makers require a spacer above the stem and an expansion plug, never a star nut.
6. Set headset preload (see Adjust headset play), align the stem, torque the bolts.

Torque

Diagram

Signs it needs doing

• Bars twist under hard braking (loose bolts)
• Creak from the faceplate
• Neck or wrist pain (wrong length or height)

Problems this fixes

• Creaking when climbing or pedaling hard
• Numb hands or sore wrists
• Sore back, neck or shoulders