Butter-Smooth Performance: A Guide to Your Fork’s 50-Hour Service

Step-by-Step: The 50-Hour Performance Service 📝

Step 1: Preparation & Depressurization

Remove the front brake caliper and wheel. If you are removing the fork from your bike, use our Dummy Fork to hold everything in place safely (including the front brake caliper). If you’re leaving the fork on your bike, use our Brake Caliper Bolt Holders to secure the caliper hardware and avoid any damage to the frame.

Note your current air pressure, compression and rebound settings. Clean the exterior of the fork thoroughly. *Crucial: Remove all air from the air spring by pressing the core valve – you can simply use an Allen Key to press the core and let the air out.

Step 2: Lower Removal

Loosen and remove the foot nuts at the bottom of the lowers. Use our Lower Leg Removal Tool(s) and, with a soft-rubber mallet, "tap" on the tool(s) to dislodge the internal shafts. Slide the lowers off over an oil drain pan or a container – oil will drip out when removing the lower leg.

Inspect for the oil for any metal debris or shiny debris. There should not be anything else than oil. If you found something unusual, you should probably contact a professional shop to get their opinion.

Step 3: The Pro Step – Air Shaft Optimization

Even brand-new forks often come from the factory with excessive grease on the air piston. This "gob" of grease can clog the bypass dimple, making the fork feel harsh or preventing it from reaching full travel.

1. Remove the Air Spring: Use your Flat Spanner and Hand Socket tool to remove the top cap. Remove the air shaft from the stanchion.
   1. To avoid scratching the air spring shaft, use your Fork Air Shaft Protector for additional protection when removing the retaining clip.
   2. Consult your manufacturer’s manual for the approved method to remove the retaining clip. Depending on the model, you may require either a retaining clip plier or a flat-head screwdriver to proceed safely.
2. Clean & Inspect: Wipe away all old, heavy factory grease from the piston and the inside of the stanchion. Use a lint-free cloth and isopropyl alcohol to deep clean the piston, seals, and the interior of the stanchion.
3. The "Less is More" Greasing: Re-apply a thin, even coat of premium suspension grease. You want it "buttery," not "clumpy." This small adjustment is the secret to a fork that tracks the ground perfectly.
4. Reinstall the Air Spring: Put the air spring back in the stanchion. Put the retaining clip back on and *double-check it is seated properly in place and in the correct orientation – you can pull a few times on the air shaft to ensure the retaining clip sits correctly into place.
   

Step 4: Seal Replacement & Cleaning

Remove old foam rings. If required, remove old dust seals (here is where you can use your DH tire lever) – *always be careful not to scratch or damage your lowers when removing the old dust-wiper seals. 

Clean the inside of the lowers with isopropyl alcohol and lint-free rags. Soak your new foam rings in fresh bath oil. By the time your new foam rings are full of oil, use your Fork Seal Driver Tool to seat the new dust wipers. Our Fork Seal Driver Tools ensure the seal goes in perfectly level and well aligned. See the How-To and Guideline page we did just for pressing new dust-wipers in place.

Once the new dust-wiper seals are in place, install the new foam rings. Then lubricate liberally the new dust seals with your favorite suspension grease.

Step 5: Oil Injection & Reassembly

Slide gently the lowers back onto the stanchions – careful not to pinch the lip of the seal and make sure of the correct orientation of the lower (making sure the arc is on the correct side versus the damper and air spring).

Pro-Tip: Use a bit of grease to maintain the dust-wipers upper spring high on the stanchions while your get the lowers back on the stanchions. Removing the dust-wipers upper spring will free the upper lip of the dust-wiper and makes it a bit easier to get the stanchions back on. Don’t forget to put the upper spring back on the dust-wipers once you are done.

Before the lowers they are fully seated, use a syringe to inject the manufacturer-specified amount of bath oil into the bottom holes of the casting.

Step 6: Finishing Touches

Install new crush washers and torque the foot bolts to spec. Re-install rebound knob. Re-inflate the air spring, cycle the fork to equalize the chambers, put the fork back on your bike (if it was removed in the first place), reinstall the front brake caliper and the front wheel. Cycle the fork again a few times to equalize the chambers – now that the fork is back on the bike, you can compress it more with you weight and arms. Re-adjust your fork to the correct SAG (see our blog post explaining what the SAG is and how to set it up), reset your compression and rebound settings, and you’re ready to shred!