The Fox Float 40 Factory eMTB suspension fork stands as a benchmark for high-performance electric mountain bike suspension. Developed with aggressive terrain and heavy-duty trail demands in mind, this fork caters specifically to the structural and damping needs of eMTBs. Designed for precision, durability, and ultimate control, it integrates top-tier technology like Kashima coating, GRIP2 damper, and updated chassis stiffness to handle intense downhill and enduro riding.
Design and Construction Overview
The Fox Float 40 Factory eMTB features a robust 40mm stanchion design paired with an eMTB-optimized chassis. Its external Kashima-coated legs enhance durability and reduce friction, while internal updates contribute to superior damping and progressive travel. The GRIP2 damper offers high- and low-speed compression and rebound adjustments, giving riders a tailored response under a wide range of trail conditions.
Fox has reinforced the fork crown and lowers to accommodate the increased loads from heavier e-bikes. The arch is shaped to improve stiffness and allow for better tire clearance without sacrificing responsiveness.
Tools Required for Installation and Maintenance
- 5mm, 6mm, and 8mm hex wrenches
- Torque wrench [paid link] with Nm scale
- Suspension fork pump
- Suspension oil (Fox 20wt Gold recommended)
- Clean workstand or bike stand [paid link]
- Isopropyl alcohol and clean rags
- Crown race setter and headset press (if changing crown race)
Installation Process
Installing the Float 40 Factory eMTB requires attention to proper torque and spacing. Begin by cutting the steerer tube to the correct length. Install the crown race compatible with your headset, followed by pressing in the headset cups if needed. Slide the fork into the head tube, ensuring headset bearings are greased and properly seated. Use a torque wrench [paid link] to tighten the stem bolts to manufacturer specifications.
The front brake caliper must be aligned to the 203mm or 220mm disc rotor size, depending on setup. Use appropriate adapters if required. Secure the axle using the floating axle design, which centers the hub independently to minimize friction and ensure precise alignment.
Adjustment and Setup
Setting up the Float 40 Factory eMTB involves balancing air pressure and damper settings for rider weight and terrain style. The recommended sag is typically 15–20% of travel.
Air spring pressure should be adjusted using the suspension pump, with Fox providing a guide based on rider weight. Next, tune the high- and low-speed compression knobs located on top of the right fork leg. High-speed compression adjusts how the fork handles big hits, while low-speed compression controls body movement and brake dive.
Rebound damping, located on the bottom of the right leg, should be adjusted in line with your compression settings to balance return speed and traction. For aggressive descending, slightly slower rebound can improve control.
Routine Maintenance Schedule
Routine servicing extends the lifespan and maintains peak performance of the Float 40. Lower leg service is recommended every 30–50 hours of ride time. This involves removing the lowers, cleaning the internals, and replacing bath oil and foam rings.
Full damper service intervals range between 100–125 hours depending on riding conditions. This service should be done by experienced mechanics or sent to an authorized service center due to the complexity of damper internals.
Inspect seals for dust and oil leakage, and ensure the stanchions are clean after every ride to prevent contamination and premature wear.
Troubleshooting Common Setup Issues
Incorrect setup can result in poor performance or premature wear. If the fork feels harsh or lacks travel, check air pressure and sag—low pressure can lead to bottoming out, while high pressure causes harsh feedback.
If there’s a knocking noise, check that the front axle is properly torqued and the brake caliper is not loose. Oil leaking from the dust seals indicates a need for immediate lower leg service.
Loss of damping adjustment range may point to a damper issue requiring a full rebuild.
Customization and Performance Tuning
Riders looking to optimize further can fine-tune using volume spacers. Adding volume spacers increases bottom-out resistance for more aggressive riding. Conversely, removing them makes the fork more linear and plush through its travel.
GRIP2 damper tuning also allows highly specific adjustments. Riders can experiment with settings on a test loop to find a setup that balances comfort, grip, and support for their weight and riding style.
Tire clearance allows customization up to 29×2.6” wheels, letting riders adapt to trail and terrain preferences.
Durability and Long-Term Reliability
The Float 40 Factory eMTB has proven durability across demanding eMTB applications. The Kashima coating resists wear and ensures smooth operation over time. Its chassis has been tested against torsional and lateral flex, holding up under repeated impact and hard descents.
Internally, the damper and air spring show little degradation in performance over hundreds of hours when properly maintained, making it a long-term investment for serious riders.
Compatibility with Other Drivetrain Components
The fork is fully compatible with 1.5” tapered steerer head tubes and standard 110x20mm Boost hubs. Brake mount compatibility is Post Mount for 203mm rotors, and adapters are needed for larger setups.
The Float 40 does not include remote lockout but integrates well with electronic drivetrains and modern cockpit configurations due to its clean cable routing and crown design.
Comparison with Similar Models
Compared to the RockShox Boxxer Ultimate, the Float 40 offers a wider tuning range through the GRIP2 damper and better small-bump sensitivity. While the Boxxer has a lighter feel, the Fox fork provides more support at mid-stroke and performs better under heavier e-bike loads.
When stacked against the Öhlins DH38 M.1, the Float 40 excels in ease of tuning and available service network, though Öhlins offers more race-oriented damping feel.
User Feedback and Field Performance
Field tests confirm that the Float 40 Factory eMTB delivers exceptional support on steep, high-speed descents and maintains traction in rocky, loose terrain. Riders appreciate the consistent feel and quick response over chattery surfaces. Its weight, while slightly higher than some competition, is justified by the added stiffness and strength for eMTBs.
FAQ
1. Is the Fox Float 40 Factory eMTB compatible with dual-crown setups on non-eMTBs?
Yes, although designed for eMTBs, it can be used on downhill bikes with compatible headsets and geometry.
2. Can I install a fender on this fork?
Yes, the arch features integrated fender mounts for Fox bolt-on fenders.
3. What rider weight range does the stock air spring support?
The stock air spring supports riders from 130 lbs to 250 lbs with appropriate air pressure tuning.
4. Do I need a torque wrench for installation?
Yes, correct torque ensures safe and precise installation, especially for axle and stem bolts.
5. How do I know when to service the damper?
If the damping becomes inconsistent or noisy, or after 100–125 hours of ride time, it’s time for a full damper service.
6. Can I upgrade to a coil spring in the Float 40 Factory eMTB?
Currently, this model is air spring-specific and does not support a coil spring conversion.
Conclusion
The Float 40 Factory eMTB is a high-caliber fork built to meet the demands of powerful, aggressive electric mountain biking. With class-leading adjustability, durable construction, and superior terrain response, it remains one of the top choices for eMTB riders tackling steep, technical trails. Its maintenance accessibility and long-term reliability make it a wise investment for performance-focused cyclists.