The Fox Float 40 Factory eMTB fork is engineered for aggressive enduro and downhill electric mountain biking. This premium suspension component demands precise maintenance and setup to ensure optimal performance on challenging terrain. Servicing your Float 40 Factory eMTB correctly not only enhances performance but also extends its lifespan, making it a vital aspect of eMTB care.
Tools Required
- 10mm and 15mm sockets
- Torque wrench [paid link]
- Suspension-specific grease
- Isopropyl alcohol and lint-free cloths
- FOX Gold 20wt and Float Fluid
- Oil measuring syringe or graduated cup
- Clean workstand
- Allen keys [paid link] (4mm, 5mm, 6mm)
- Damper removal tool (if damper service is required)
- Pick or seal puller tool
Installation Procedure
Installing the Fox Float 40 Factory eMTB requires precision and adherence to torque specifications. Begin by securing the steerer tube into the frame’s head tube and aligning the fork with the front wheel. When fastening the crown race and stem, ensure even clamping force to avoid distortion. The axle system, which uses a floating design, must be tightened to the specified torque (19.5 Nm) to maintain correct alignment and minimize stiction. Brake calipers must be centered carefully to avoid rotor rub. Cable routing, especially for eMTBs, should follow factory guides to prevent interference with suspension travel.
Initial Setup and Sag Adjustment
Once installed, setting up the fork according to rider weight and terrain is critical. Begin by checking the air spring pressure. FOX recommends approximately 72 psi for a 72 kg rider; adjust proportionally based on rider weight. With gear on, the rider should sit in a neutral riding position to measure sag—targeting 15–20% of the fork’s total travel (200 mm). Adjust air pressure incrementally and recheck sag until the desired level is achieved. Rebound and compression dials on the right stanchion should be adjusted next. Start at the midpoint of both ranges, then fine-tune according to trail conditions and rider preference.
Routine Maintenance Schedule
Routine maintenance is essential to keep the Float 40 Factory eMTB fork operating at peak performance. After every 30 hours of riding, perform a lower leg service. This includes draining and replacing the bath oil, cleaning the inside of the lower legs, and inspecting dust wipers and foam rings for wear. At 100 hours, a full damper and air spring service is recommended. This involves removing the damper shaft, inspecting internal seals, and re-lubricating the air piston with Float Fluid. Avoid using general-purpose greases as they can degrade suspension seals.
Troubleshooting Common Setup Issues
A common issue with the Float 40 Factory is excessive stiction, usually due to over-tightened pinch bolts or dry dust wipers. Ensure bolts are torqued correctly and re-lubricate the seals using suspension-specific grease. If the fork bottoms out too easily, verify air pressure and compression settings; the addition of volume spacers in the air chamber may also be necessary. Noisy operation during compression often signals the need for oil top-up or a damper bleed. Uneven fork travel, where one leg compresses more than the other, typically points to improper axle installation or internal cartridge wear.
Air Spring and Damper Service Instructions
To service the air spring, release all air pressure via the Schrader valve and disassemble the top cap using a 26 mm socket. Remove the air shaft, clean it with isopropyl alcohol, and apply fresh Float Fluid to the piston seals. For damper service, remove the lower bolt and pull out the damper shaft. Inspect the IFP (Internal Floating Piston) and bleed the damper if any air bubbles are present. Use a syringe to add the correct amount of FOX Gold 20wt oil into the damper side. Reassemble and torque all bolts to specification, ensuring no cross-threading or contamination.
Customization for Performance Optimization
Advanced riders may want to modify the Float 40 Factory to better suit specific riding styles. Volume spacers in the air spring can be added or removed to adjust progression. The GRIP2 damper allows high and low-speed rebound/compression adjustments—ideal for tuning fork response in varied terrain. Switching to stiffer or softer fork springs is unnecessary with the air system but tuning the negative air spring via the equalization port can refine mid-stroke support. For eMTB-specific performance, ensure battery weight is accounted for in setup tuning.
Compatibility with Other Components
The Float 40 Factory is compatible with most eMTB frames that accept dual-crown forks and feature 20mm thru-axle front hubs. However, compatibility with headsets must be confirmed, especially for integrated or zero-stack systems. The fork works optimally with FOX or Shimano disc brakes due to their caliper mount design but can also be paired with SRAM models. It is essential to verify rotor size compatibility—Fox recommends a minimum of 203mm for safe performance. The fork is not compatible with standard MTB hubs or quick-release systems.
Comparison with Similar Suspension Models
Compared to the RockShox Boxxer Ultimate, the Float 40 Factory offers more granular damper control with the GRIP2 system. While the Boxxer is lighter, the Fox provides better small-bump compliance and mid-stroke support—crucial for heavier eMTBs. Against the Öhlins DH38, the Float 40 is more customizable through its broader compression tuning range. The Factory’s Kashima coating also gives it a performance edge in reducing friction and improving long-term durability. Riders seeking maximum adjustability and stiffness will find the Float 40 superior in aggressive downhill contexts.
Longevity and Warranty Considerations
To ensure long-term reliability, the Float 40 Factory must be serviced according to FOX’s maintenance intervals. Using non-recommended fluids or neglecting services can void the warranty. The fork includes a limited warranty covering defects in materials or workmanship for a period of one year from the original purchase date. Always retain purchase documentation and follow FOX’s service logs to maintain coverage.
Storage and Transport Guidelines
When storing the Float 40 Factory-equipped eMTB, keep the fork upright to prevent oil pooling in the lower legs. If transporting the bike by car rack, avoid direct exposure to prolonged sun and ensure the fork is not compressed for extended periods, which can stress seals. During air travel, reduce air pressure to atmospheric levels to prevent internal seal damage caused by cabin pressure differences.
FAQs
1. How often should I service the Float 40 Factory eMTB fork?
Basic lower leg service is recommended every 30 riding hours, with a full damper and air spring overhaul every 100 hours.
2. What oil weight should be used in the Float 40 Factory fork?
Use FOX Gold 20wt oil for the damper and bath sections, and Float Fluid for air chamber lubrication.
3. Can I install this fork on a standard mountain bike?
No, the Float 40 Factory is designed for eMTBs and downhill frames that can accommodate dual-crown forks and 20mm axles.
4. My fork is not returning to full travel. What’s wrong?
Check for air pressure loss, excessive oil viscosity, or trapped air in the damper. A full air spring service may be required.
5. What’s the benefit of the Kashima coating?
Kashima provides a low-friction, hard-wearing surface on the stanchions, resulting in smoother action and extended durability.
6. How do I adjust rebound and compression correctly?
Start at the midpoint of each dial’s range. Then fine-tune based on trail conditions, using small increments to test response.
Conclusion
Servicing the Fox Float 40 Factory eMTB fork requires attention to detail, regular maintenance, and correct setup techniques. With proper care, this high-performance suspension fork delivers consistent performance and durability under the rigors of electric mountain biking. Riders looking to maintain a competitive edge will benefit from understanding the intricate workings and service protocols of this premium component.