How to pressurize a damper with a Needle Air Fill tool?

How to Pressurize or Depressurize a Damper Using a Needle Fill Tool

This guide explains how to safely depressurize and re-pressurize a damper using a needle air-fill adapter. This is commonly required for shocks with IFP or bladder systems such as Cane Creek DB Inline, Fox DPX2, Float X, Öhlins, EXT, Push, and others.

Do You Really Need Nitrogen?

Short answer: no, you don’t need nitrogen to pressurize a shock at home. Even if the manual says “nitrogen”, here’s the reality:

  • Air is already ~78% nitrogen.
  • The remaining gases only matter at extremely high pressures (1000+ psi), which MTB dampers never reach.
  • Thermodynamic differences exist, but at typical IFP pressures (100–300 psi), they are irrelevant in practice.
  • Fox themselves recommend air for forks and most shocks.
  • Nitrogen is mainly used for lab repeatability, compact design constraints, and slightly better pressure retention after pump removal.
  • Shocks without a piggyback (Fox DPS, RockShox Deluxe) can run higher pressures (300–550 psi), which is intimidating but still perfectly manageable with the right pump.

Bottom line: a normal shock pump and air work exactly the same.

What You Need
  • Needle air fill adapter (metal or plastic base)
  • Pellet retainer tool
    • Plastic retainer for soft pellets (Cane Creek)
    • Metal retainer for harder pellets (Fox DPX2 / Float X)
  • Shock pump rated at least 300 psi + bench vise
  • Shocks without piggyback: 600 psi shock pump recommended
Step 1 – How to Depressurize the Damper
  1. Insert the needle into the pellet with the shock pump attached.
  2. If pressure is present, release it slowly using the pump valve.
  3. Remove the needle.
  4. Open the bleed screw very slowly.
  5. If the damper is highly aerated and the IFP is fully seated:
    • Place the shock inside a sealed plastic bag.
    • Carefully open the bleed screw through the bag.
    • Never point the port toward yourself. Pressurized oil can eject several meters. Wear eye protection.
Step 2 – How to Pressurize the Damper
  1. Ensure the damper is fully reassembled (including correct IFP depth if applicable).
  2. Install the pellet retainer into the 4 mm Allen interface.
  3. Gently insert the needle into the center of the pellet while slightly rotating it. Do not force it, or you may bend the needle and damage the pellet.
  4. Tighten the pellet retainer just enough to hold the needle in place.
  5. Inflate slowly using the shock pump.
  6. Once target pressure is reached, pull the needle out quickly and immediately snug the pellet.
  7. Pellet torque guidelines:
    • Fox: higher torque required
    • Cane Creek: very low torque (soft pellet)
  8. Cycle the shaft. It should return smoothly with no squishy feel.
Helpful Tips
  • Metal-based needles last significantly longer.
  • Never bend the needle. Rotate gently during insertion.
  • Only use plastic pellet retainers on soft pellets.
  • Many brands do not use pellet retainers at all.
  • If pressure escapes after removal, retry calmly.
  • Inconsistent rebound usually means poor bleed or incorrect pressurization.

⚠️ Warning: Incorrect damper pressurization can cause injury or component failure. Always wear safety glasses, avoid overtightening plastic parts, and fully depressurize before service. By using this guide, you agree to our Terms of Service.