Regular maintenance of your Fox Float 36 Rhythm eMTB fork ensures optimal suspension performance and longevity. Among the most critical maintenance tasks is changing the lower leg oil. This procedure not only maintains plushness and damping efficiency but also protects internal components from premature wear. This article walks you through every step of the oil change process specifically for the Float 36 Rhythm model.
Tools Required
- 10mm socket or wrench
- 5mm hex key [paid link]
- 2mm hex key (for bleed valve removal if equipped)
- Torque wrench [paid link] (capable of reading inch-pounds)
- Suspension-specific lower leg oil (Fox 20wt. Gold recommended)
- Clean lint-free rags
- Suspension fork grease (e.g., Slickoleum)
- Plastic syringe or oil measuring cup
- Seal kit (if replacing)
- Soft mallet or rubber hammer
- Drain pan or catch container
- Isopropyl alcohol (90% or higher)
Preparation and Safety
Before beginning the procedure, ensure the bike is securely mounted in a work stand and the front wheel is removed. Release any remaining air pressure from the fork using a shock pump and the appropriate valve. Avoid performing this procedure if you lack the necessary tools or technical confidence—improper handling can damage the fork internals or compromise performance.
Removing the Lower Legs
To access the lower legs of the Float 36 Rhythm, start by loosening the foot nuts at the bottom of each leg. Use a 10mm socket for the damper side and a 5mm hex key [paid link] for the air spring side. Leave the nuts threaded partially to protect the threads during the next step. Using a soft mallet, gently tap each bolt upward to dislodge the internal shafts from the lower legs. Oil will begin to drain, so position a catch pan beneath the fork.
Once the shafts are free, fully remove the bolts and gently slide the lower legs off the stanchions. If they resist, avoid forcing them—check that all bolts are fully disengaged and that the legs aren’t snagged on seals or bushings.
Cleaning and Inspection
With the lower legs removed, wipe down the stanchions and inner surfaces using isopropyl alcohol and a clean, lint-free rag. Inspect the inside of the lower legs for contamination or damage. Pay close attention to the condition of the foam rings, oil seals, and wipers. If any parts are cracked, excessively worn, or torn, replace them using a Fox seal kit.
Foam rings should be saturated with suspension oil before reinstallation. Soak them in a small container of Fox 20wt. Gold for at least 10 minutes to ensure they are fully saturated.
Reinstalling the Lower Legs
After cleaning, apply a light coating of suspension grease around the inside of the wiper seals to aid reinstallation and minimize friction. Carefully slide the lower legs back onto the stanchions, taking care not to pinch or fold the seals.
Stop short of full installation to allow for precise oil volume application. Use a syringe to measure and inject 20cc of Fox 20wt. Gold into each lower leg. The exact volume may vary slightly depending on your specific Rhythm variant, so always refer to Fox’s official service specifications for the correct oil quantity.
Securing the Lower Legs
Once the oil is in place, press the lower legs up until the foot studs are visible through the bolt holes. Thread the air spring bolt (5mm hex) and the damper bolt (10mm socket) carefully by hand. Tighten the bolts using a torque wrench [paid link] to the manufacturer’s specified values—typically 5.1 Nm (45 in-lbs) for both bolts.
Reinstall any bleed valves or bottom caps that were removed. Use a 2mm hex key for the bleed valves, if equipped.
Refilling Air Pressure and Testing
Once reassembled, use a shock pump to refill the fork to your desired air pressure based on rider weight and riding preference. Check for proper sag and rebound settings. Before riding, cycle the fork a few times to ensure full travel is available and to allow the new oil to distribute evenly within the lower legs.
Perform a quick visual check for any leaks or inconsistencies. If anything appears unusual, recheck all bolts and seals before proceeding.
Troubleshooting Common Issues
If the fork feels sticky after reassembly, it may indicate under-lubrication or improper seal seating. In such cases, disassemble and inspect the foam rings and seals for proper oil saturation.
A persistent oil leak around the bottom bolts can result from over-torquing or damaged crush washers. Always replace these washers when performing an oil change to maintain sealing integrity.
If the fork exhibits clunking or excessive movement, verify that both bolts are correctly torqued and that the lower legs are properly aligned.
Customization and Optimization Tips
The Float 36 Rhythm is designed with simplicity in mind but offers subtle customization through volume spacers and air spring tuning. Riders looking for more progression can add volume spacers to the air spring, enhancing bottom-out resistance. Make these adjustments during the oil change to consolidate maintenance time.
Additionally, adjusting rebound and compression damping to suit riding style and terrain can make a significant difference in comfort and control. While the Rhythm model offers limited external adjustments, using proper oil volume and fresh seals will maintain its performance envelope.
Compatibility and Model-Specific Considerations
The Fox Float 36 Rhythm eMTB fork is built around the same chassis as higher-end models but uses a GRIP damper and slightly different internals. It is crucial to use oil volumes and parts specifically listed for the Rhythm variant, as tolerances may differ from the Performance Elite or Factory models.
This fork is compatible with most standard 36mm Fox stanchion components, but internal upgrades are limited. When replacing parts like seals or foam rings, always confirm compatibility using Fox’s service guides.
Model Comparison and Selection
Compared to the Factory and Performance Elite lines, the Rhythm fork prioritizes durability and affordability over tunability. Riders who want high-end adjustability (like HSC/LSC or FIT4 damper control) may prefer upgrading. However, for eMTB applications, the Rhythm offers dependable performance with lower maintenance demands.
It’s also less complex internally, making DIY maintenance like oil changes more straightforward for those with mechanical aptitude.
Conclusion
Changing the lower leg oil on the Fox Float 36 Rhythm eMTB fork is a manageable DIY task with the right tools and preparation. Regular service every 30 to 50 hours of riding helps sustain plush travel, reduce wear, and maintain consistent damping. With correct oil volume, new seals when needed, and proper reassembly torque, your suspension will continue to perform reliably across all terrains.