Repair guides › Suspension
Fork lower-leg service (every 50–125 hours)
A fork with a spring (coil or air) and damper so the front wheel can move up over bumps. Stanchions (upper tubes) slide into lowers on bushings. A spring holds you up; a damper controls how fast it rebounds. Wiper seals keep dirt out. Air forks are tuned with a shock pump; coil forks with a preload knob.
Open this job in RideLoadout▶ Watch it done
Tools
- Ball-end hex key set (1.5–10 mm): Park Tool HXS-1.2 Professional L-Shaped Hex Set ($$)
- 1/4" click torque wrench (about 2–17 Nm) + bits: Pro Bike Tool 1/4 inch drive click torque wrench set (2.2–16.9 Nm) ($$)
- Shop rags + nitrile gloves: shop towels and nitrile gloves ($)
- Isopropyl alcohol 91%+: isopropyl alcohol 91% ($)
- Repair stand: Park Tool PCS-9.3 Home Mechanic Repair Stand ($$$$)
- 3/8" ratchet + 14/15 mm sockets + 8 mm hex bit: TEKTON 3/8 inch drive socket set metric ($$)
- Soft mallet + star-nut setter: Rubber mallet + star nut setting tool ($$)
- Shock pump: RockShox High Pressure Shock Pump ($$)
- Fork oil + suspension grease: Slick Honey suspension grease and RockShox 0W-30 fork oil ($$)
- Fork seal driver: RockShox fork seal installation tool ($$)
Compare Good, Better and Best for each tool
Steps
- Note your air pressure and rebound clicks. Let all air out of the air spring.
- Remove the front wheel and brake caliper. Put a pan under the fork.
- Unthread the bolts at the bottom of each leg 3–4 turns, then tap each bolt with a soft mallet to free the shafts. Oil will drain.
- Remove the bolts and pull the lowers off the stanchions.
- Clean stanchions and the inside of the seals with a clean rag (no solvents on seals). Check seals and foam rings for damage.
- Soak the foam rings in fresh fork oil, put them back, smear seal grease on the wipers.
- Slide the lowers back on, add the bath oil volume your fork's manual lists into each leg through the bolt holes, refit the bolts.
- Refit the wheel (close the QR or torque the axle) and the caliper (6–8 Nm), and test the front brake. Then air up to your old pressure and set sag and rebound.
Torque
| Fastener | Torque |
|---|---|
| Lower leg bolts/nuts | Fox 5.6 Nm · RockShox ~6.8 Nm (check fork manual) |
| Caliper mount bolts | 6–8 Nm (Shimano/Tektro) · SRAM/Avid 9.5 Nm · check the caliper |
Diagram
Taken apart, seen from the frontFork
Signs it needs doing
- Fork bottoms out with a clunk
- Oil ring on the stanchions
- Sticky, notchy movement
- Fork tops out with a clunk (rebound too fast)