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Dust and dirt from the trails can easily get into the inside of the fork casting. Conversely, some lubricating oil can also escape from the inside of the suspension fork via the dust wipers. Either way, the function of the fork decreases from ride to ride. However, this does not mean that the entire fork needs to be serviced. This is because modern damping cartridges have hardly any abrasion and therefore only very little wear. In addition, the oil circuit of the damping cartridge is completely separate from the increasingly contaminated lubricating oil in the casting. The damping oil therefore lasts significantly longer than the lubricating oil.
Experience has shown that servicing a mountain bike fork every 50 operating hours would be excessive. However, if you replace the lubricating oil regularly, you can enjoy a smoothly responding suspension fork for longer. The small fork service only takes about 20 minutes for experienced mechanics and can be carried out without special tools. In this article, we use a Rockshox fork to explain how you can service your MTB suspension fork in just a few steps and get it ready for your next ride.
MTB suspension fork maintenance: instructions
Preparations: The fork must be removed from the frame for the minor service. To do this, remove the wheel and brake and loosen the stem and headset bolts. Then it is best to remove the bike from the Mounting stand and put it down. For the work, the fork is clamped with the steerer tube in the assembly stand. Let the air out of the fork for safety reasons.
Remove the rebound knob: On Rockshox forks, the red rebound adjuster wheel is located at the bottom of the right fork leg (from the rider's perspective). Pull firmly on the adjusting wheel and place the component on the workbench.
With Fox forks or older Rockshox models the rebound adjuster wheel is secured with a small screw on the side (detail) or in the centre of the rebound knob in addition to the plug connection.
Loosen the screws: Then loosen the bolts on the underside of the two fork legs by three to four turns. For our Rockshox Sid, you will need a 5 mm Allen key. For Fox forks or older Rockshox models, you will need a 10mm socket and a small ratchet. ATTENTION: Only loosen the screws by a few turns, do not unscrew them completely.
Release the pressing: The piston rod of the cartridge and the air shaft are pressed together with the casting. To dismantle the fork, you must loosen the compression. To do this, insert the tool with which you have just loosened the bolts at the lower end of the fork into the bolt and tap the tool lightly with a rubber mallet. It is best to hold the fork casting while doing this.
Pull off the casting: The pressing must be tapped on both sides of the suspension fork as described in step 4. Then completely unscrew the bolts at the lower end of the suspension fork and set aside. Position the suspension fork horizontally and carefully remove the casting. If this requires a lot of force, the compression is not yet fully released.
Allow oil to run out: Place the fork casting vertically over a container and allow the oil to run out of the openings in the fork. Caution: Used oil must be disposed of separately! There are foam rings soaked in oil behind the dust wipers at the upper end of the fork casting. Carefully remove these from the recess by hand or with a small, pointed tool.
Optional - remove scraper: If you wish, you can also carefully lever the rubber wipers out of the casting using a tyre lever or open-end spanner. In most cases, however, this is unnecessary because the wipers are often not worn out. You also need a special tool to fit new wipers. The wipers cannot usually be knocked into place with a hammer and nut alone.
Clean the casting: Once the oil has drained completely, you can clean the casting with isopropyl alcohol. ATTENTION: Do not use brake cleaner. This leaves behind residues that are harmful to the fork coatings. Carefully wipe out the inside of the casting and the coated stanchions with a cloth and dry before the next work step.
Soak new foam rings: The foam rings removed in step 6 can be reused after cleaning with a cloth. In the event of severe deformation, we recommend new Foam rings in the lubricating oil of the fork. Then reinsert the soaked foam rings underneath the rubber wiper in the recess provided in the casting.
Grease the dust wiper: Once the dust wipers have been cleaned, the surfaces that come into contact with the stanchions are greased with special grease. Rockshox uses the following for this Sram butter , Fox recommends the RSP slick kick fork grease. CAUTION: Be sure to use one of the special greases and NOT conventional grease used for the headset or bottom bracket.
Combine immersion and standpipes: Slide the casting with the impregnated foam rings back over the standpipes. Make sure that both dust wipers do not fold in when the components are pushed together. Do not push the fork all the way together yet. Do not forget to fit the rubber ring for the sag indicator and slide the casting onto the stanchions the right way round.
Measure the oil: Fox and Rockshox offer special lubricating oils for their MTB suspension forks. However, you can also rely on suppliers such as Motorex can be used. It is important that the oil has the correct viscosity. Rockshox forks require 0W30 oil. Fox forks should be filled with our own 20WT Gold oil. The exact filling quantities for the lubricating oil can be found in the respective operating instructions.
Press lubricating oil into the lower part: Our Rockshox SID fork only needs five millilitres of 0W30 lubricating oil in both the left and right fork leg. Measure out the correct amount with a syringe and pour it into the open holes of the fork casting (step 4). To do this, turn the fork steerer downwards at an angle so that the lubricating oil can no longer run out. Then push the fork completely together.
Screw together the standpipes and immersion pipes: Once the fork is completely pushed together, the threads of the air shaft and piston rod are visible in the openings of the fork casting. Then refit the Allen screws removed in step 5. ATTENTION: The red bolt must be installed on the damping side (on the right from the rider's perspective). Rockshox specifies a tightening torque of only 6.8 Nm.
Attach the rebound knob: Now refit the rebound control wheel. To do this, simply press the component removed in step 2 firmly into the opening provided. For Fox suspension forks or older Rockshox forks, clamp the adjustment wheel back onto the corresponding metal pin using the small grub screw. If you have deflated the fork for safety reasons, you can now re-inflate it.
Install fork: Clean the fork with a cloth so that no oil residue gets onto the brake. Then you can reinstall it in the frame. How to install the fork correctly and also clean the We explain how to grease the headset in this screwdriver guide and video . How to use the In this service article, we show you how to adjust the brakes correctly and provide tips in the video .
Suitable spare parts for the suspension fork service
Every suspension fork manufacturer, such as Rockshox, Fox or Manitou, offers the corresponding forks. Service kits is available. This includes all the necessary seals, the foam rings and the matching dust wipers.
