Repair guides › Frame & Fork
Fork and thru-axle check
Holds the front wheel and steers, with no suspension. Usually carbon or aluminum on road and gravel bikes, clamped by a 12 mm thru-axle. The steerer runs up through the head tube, held by the headset bearings. A 12 mm axle threads through one leg into the other, so the wheel always sits in the same place. Most use a flat-mount disc caliper on the left leg.
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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
- Look down at the wheel between the fork legs: the gap should be equal. Thru-axles always center the wheel, so an off-center wheel means the axle is not fully threaded in.
- Undo the axle, re-seat the wheel, thread the axle fully and tighten (lever firmly closed, or 10–15 Nm for a bolt axle).
- Check the caliper mount bolts (6–8 Nm). Run a finger along both legs and the crown: any crack, deep chip or soft spot in carbon means stop riding it.
Torque
| Fastener | Torque |
|---|---|
| Thru-axle | 10–15 Nm (check marking) |
| Caliper mount bolts | 6–8 Nm (Shimano/Tektro) · SRAM/Avid 9.5 Nm · check the caliper |
Signs it needs doing
- Knocking when you brake hard (often the headset, not the fork)
- Creak from the axle (needs a light grease)
- Cracks or chips in carbon after a crash