The Fox Float 40 Factory eMTB suspension fork has quickly gained recognition among aggressive e-mountain bike riders for its race-proven performance and robust construction. Engineered specifically for electric mountain bikes, the Float 40 Factory series is a testament to precision damping, superior control, and customization potential.

Tools Required

• Torque wrench [paid link] with hex bits
• 36mm socket or Fox Top Cap Tool
• Suspension pump
• Caliper for rotor alignment
• Fox damper and lower leg service kit
• Clean rags and isopropyl alcohol

Installation of the Float 40 Factory eMTB Fork

Installing the Float 40 Factory fork requires careful attention to torque specifications and headset compatibility. Begin by confirming that your frame is rated for dual-crown forks, as the Float 40’s double crown setup is non-negotiable for safety.

Insert the steerer tube through the headset, applying light grease to headset bearings. Ensure the top and bottom crowns are aligned, and tighten the steerer bolts to 5.1 Nm. Next, install the brake caliper using manufacturer-recommended bolts and torque settings (6.8 Nm typical for post-mount bolts). If your eMTB uses a front fender, use the integrated fender mounts with the provided M5 hardware. Complete the setup by aligning the axle and torqueing it to 19 Nm.

Adjusting Suspension Settings for Performance

Initial setup involves dialing in the appropriate air pressure via the EVOL air spring. Fox recommends beginning with body weight in pounds divided by 2.75 to calculate PSI, though adjustments should reflect terrain and rider style. Use a suspension pump to add or release air through the Schrader valve located on the top of the left leg.

The FIT GRIP2 damper offers high- and low-speed compression and rebound settings. Turn each adjuster knob clockwise to increase damping. Baseline settings usually involve 8-10 clicks from fully closed. Fine-tune compression to control mid-stroke support and rebound to prevent packing over repeated hits.

For coil-like suppleness, the Float 40 Factory uses volume spacers. Adding spacers increases end-stroke progression, which benefits riders tackling steep or technical descents. Remove the air top cap with a 36mm socket to install or remove spacers. Always re-torque the top cap to 40 Nm after adjustments.

Routine Maintenance and Service Intervals

To maintain peak performance, inspect lower leg oil and foam rings every 40 hours of riding. Replace the oil with Fox 20wt Gold and clean the wiper seals with isopropyl alcohol. The FIT GRIP2 damper and air spring require a full overhaul every 125 hours, including fresh O-rings, damper oil, and grease.

Cleaning the fork stanchions after every ride prevents dust buildup. Always check for oil leakage around the seals, which may indicate worn bushings or torn seals requiring immediate attention.

Troubleshooting Common Issues

Performance issues such as harsh travel, inconsistent rebound, or sagging can be traced to specific causes. If the fork feels sticky or harsh, inspect the air pressure and confirm the presence of adequate lower leg oil. Use the service port to release any air trapped between the air spring and negative chamber, which can impact performance.

Inconsistent rebound response often stems from incorrect damper tuning. Reset adjusters to baseline and make small incremental changes. If damping still feels inconsistent, the damper may require bleeding or a rebuild.

Sagging or excessive dive under braking typically indicates insufficient air pressure or a lack of volume spacers. Verify settings against your terrain and riding intensity. In rare cases, a faulty air piston may be responsible and will need to be replaced.

Customization and Performance Optimization

The Float 40 Factory excels in tuning range. Advanced riders can customize their fork using a telemetry system to log travel usage and rebound data. This allows micro-adjustments to shim stacks and compression valving, although such modifications are best performed by certified Fox technicians.

Stanchion coating plays a role in reducing friction. The Kashima Coat used in the Factory series improves sensitivity and longevity over rough terrain. Riders who value small bump compliance will notice the benefit immediately compared to black anodized stanchions.

For weight-conscious eMTB riders, pairing the Float 40 with a carbon crown steerer assembly (aftermarket) can drop approximately 100 grams without compromising stiffness.

Comparison with Similar Fork Models

Compared to the Fox 38 Factory, the Float 40 offers increased chassis stiffness due to its dual-crown design, which suits enduro and downhill eMTB use. While the 38 is lighter and better suited to trail eMTBs, the Float 40 is unmatched in downhill stability and resistance to brake dive.

The RockShox BoXXer Ultimate offers a similar high-performance dual-crown setup but uses the Charger 3 damper system. Riders often cite the Float 40’s broader tuning range and more supportive mid-stroke feel as key advantages.

Marzocchi’s Bomber 58 is another competitor, sharing the same chassis as the Float 40 but with a simpler GRIP damper. It’s a better budget option but lacks the damping finesse and adjustability of the GRIP2-equipped Float 40.

Component Compatibility and Drivetrain Considerations

The Float 40 Factory fork is compatible with both 27.5” and 29” front wheels, provided the offset and axle standards match. It features a 20mm thru-axle which must pair with matching hub spacing (110mm Boost standard).

Brake compatibility includes post-mount setups for 200mm and 203mm rotors without adapters. Riders using SRAM or Shimano 4-piston calipers can expect consistent bite and fade resistance due to the fork’s chassis rigidity.

The steerer tube is 1.125” straight, requiring a specific head tube and upper crown race. For integrated cockpits, ensure proper torque to prevent bar slippage due to the added mass of eMTB setups.

Conclusion

The Fox Float 40 Factory eMTB fork stands out for its precision, durability, and unparalleled adjustability. Its advanced damper and air spring system, combined with dual-crown stiffness, make it a top choice for serious eMTB riders tackling demanding terrain. With routine maintenance and careful setup, the Float 40 offers confidence, control, and performance that matches the demands of modern electric mountain biking.