8.2 suspension

Lower Leg Service (Suspension Fork)

The most important regular suspension service. Recommended every 50–100 hours or annually.

Difficulty ★★★ advanced
Time ~60 min
Applies to Bikes with suspension fork

Tools

  • Standard workshop tools

Procedure

  1. Release all air pressure

    from the fork via the air valve.

  2. Remove the front wheel.

  3. Remove the brake caliper

    from the fork (don't disconnect the hose; tie it up out of the way).

  4. Place the fork upside down

    in the workstand or vise (clamp on the steerer with a clamp protector).

  5. Loosen the lower leg bolts

    at the bottom of each fork leg (5 or 8mm hex). On RockShox, these are usually 5mm hex.

  6. Unscrew each bolt several turns

    — but don't remove fully. Use a soft mallet to gently strike the bolt heads to break the air spring shaft and damper shaft loose from the lowers.

  7. Now fully remove the bolts.

  8. Slide the lowers off

    the upper tubes / stanchions.

  9. Drain the old oil

    from the lowers into the catch pan. Note the volume — should match the spec (typically 5–15 ml per leg, plus a "bath oil" amount in the lowers).

  10. Wipe the lowers clean

    inside.

  11. Inspect the foam rings

    (orange or green rings around the dust wipers inside the lowers). They look like wet o-rings of foam. Replace them — the new ones come pre-lubricated, or you soak them in fresh suspension oil for a few minutes before installation.

  12. Inspect the dust wipers

    (the rubber lip seals at the top of the lowers). If torn or hardened, replace using a seal driver.

  13. Apply fresh suspension oil

    to the inside of the dust wipers and to the upper tubes.

  14. Slide the lowers back over the upper tubes

    carefully — don't damage the dust wipers.

  15. Add the spec'd amount of bath oil

    through the lower leg bolt holes (varies — typically 10–30 ml per leg). Use a syringe for accuracy.

  16. Thread the lower leg bolts back in

    by hand to start, then tighten to spec (typically 7 Nm for a RockShox, but check yours).

  17. Re-pressurize the air spring

    to your previous pressure (or set new sag).

  18. Cycle the fork several times

    through its travel to redistribute oil.

  19. Reinstall caliper and wheel.

    > The above is generic — specific procedures vary considerably by brand/model. Always check the manufacturer's service manual for your exact fork. ---

The most important regular suspension service. Recommended every 50–100 hours or annually.

Tools (RockShox example, varies by fork): 5mm and 8mm hex, suspension oil (RockShox 0W-30 PIT for lowers), seal driver if replacing seals, catch pan, syringes for measuring oil, fresh foam rings (in the service kit), rags.

Procedure #

  1. Release all air pressure from the fork via the air valve.
  2. Remove the front wheel.
  3. Remove the brake caliper from the fork (don’t disconnect the hose; tie it up out of the way).
  4. Place the fork upside down in the workstand or vise (clamp on the steerer with a clamp protector).
  5. Loosen the lower leg bolts at the bottom of each fork leg (5 or 8mm hex). On RockShox, these are usually 5mm hex.
  6. Unscrew each bolt several turns — but don’t remove fully. Use a soft mallet to gently strike the bolt heads to break the air spring shaft and damper shaft loose from the lowers.
  7. Now fully remove the bolts.
  8. Slide the lowers off the upper tubes / stanchions.
  9. Drain the old oil from the lowers into the catch pan. Note the volume — should match the spec (typically 5–15 ml per leg, plus a “bath oil” amount in the lowers).
  10. Wipe the lowers clean inside.
  11. Inspect the foam rings (orange or green rings around the dust wipers inside the lowers). They look like wet o-rings of foam. Replace them — the new ones come pre-lubricated, or you soak them in fresh suspension oil for a few minutes before installation.
  12. Inspect the dust wipers (the rubber lip seals at the top of the lowers). If torn or hardened, replace using a seal driver.
  13. Apply fresh suspension oil to the inside of the dust wipers and to the upper tubes.
  14. Slide the lowers back over the upper tubes carefully — don’t damage the dust wipers.
  15. Add the spec’d amount of bath oil through the lower leg bolt holes (varies — typically 10–30 ml per leg). Use a syringe for accuracy.
  16. Thread the lower leg bolts back in by hand to start, then tighten to spec (typically 7 Nm for a RockShox, but check yours).
  17. Re-pressurize the air spring to your previous pressure (or set new sag).
  18. Cycle the fork several times through its travel to redistribute oil.
  19. Reinstall caliper and wheel.

The above is generic — specific procedures vary considerably by brand/model. Always check the manufacturer’s service manual for your exact fork.