The Float 40 Factory eMTB by Fox is engineered specifically for the demands of electric mountain bikes, blending robust performance with cutting-edge adjustability. Designed for downhill riders and gravity-focused eMTB enthusiasts, this model sets a high standard with its superior damping technologies and e-MTB-specific chassis strength.
Tools Required
- 5 mm and 6 mm hex keys [paid link]
- Torque wrench [paid link]
- Suspension pump
- Fox suspension oil and fluid guide
- Clean rags and isopropyl alcohol
- Cassette lockring tool [paid link] (for wheel removal, if necessary)
Installation of the Float 40 Factory eMTB
Proper installation of the Float 40 Factory eMTB fork ensures optimal performance and long-term reliability. Begin by confirming the steerer tube length matches your bike’s head tube and stem stack. After trimming the steerer (if necessary), install the star nut and press the crown race onto the fork’s crown.
Once positioned in the head tube, the steerer should be aligned with spacers and stem, then preloaded and torqued to manufacturer specifications. Axle installation requires careful alignment of the lowers with the front wheel’s hub. The floating axle design demands accurate setup using the pinch bolt alignment method described in Fox’s service manual to prevent bushing bind and enhance small bump sensitivity.
Adjustment Settings for Performance Tuning
The Float 40 Factory eMTB features high- and low-speed compression adjusters, as well as high- and low-speed rebound controls. The Grip2 damper delivers precise tuning for riders seeking maximum control on technical terrain. Begin with Fox’s recommended base settings based on rider weight and terrain type, then dial in fine adjustments through test runs.
Air spring pressure can be tuned with a suspension pump. Riders should adjust sag to 15–20% of total fork travel. Use volume spacers to fine-tune progressiveness; more spacers increase ramp-up for aggressive riding, while fewer allow for a more linear stroke suited to moderate terrain.
Routine Maintenance for Long-Term Durability
Consistent maintenance preserves the performance and responsiveness of the Float 40 Factory eMTB. Lower leg service should be performed every 30–50 hours of riding. This includes removing the lowers, cleaning seals, and replacing the bath oil. Fox recommends 20-weight Gold oil for optimal lubrication.
Every 100–125 hours, a full damper and air spring service is advised. This involves disassembling the air spring assembly, cleaning, and re-lubricating internal seals, as well as bleeding and refilling the damper with Fox-approved fluid. Always inspect for wear on bushings, seals, and stanchion coatings to prevent premature damage.
Troubleshooting Common Issues
When improperly set up, riders may notice harsh compression or inconsistent rebound. These symptoms are often linked to incorrect air pressure or damper settings. Excessive friction or stiction typically points to bushing misalignment or dirty seals. Floating axle misalignment can also lead to binding—re-check pinch bolt torque and axle float position.
Oil leaks from the wiper seals indicate worn or dirty seals, necessitating a lower leg service. If rebound or compression dials are unresponsive, the damper may need inspection for contamination or cavitation.
Customization and Performance Optimization
The Float 40 Factory eMTB offers broad customization through volume spacers, adjustable air pressure, and multi-axis damping adjustments. Riders can tune each parameter independently, enabling setups tailored for freeride, downhill racing, or aggressive trail riding.
Switching to a firmer or lighter air spring curve via volume spacers changes how the fork behaves in end-stroke conditions. Adjusting high-speed compression aids in absorbing square-edge hits, while low-speed compression can firm up fork behavior under braking or cornering loads.
Compatibility With eMTB Systems and Components
Designed specifically for eMTBs, the Float 40 Factory fork features reinforced lowers and stanchions to withstand increased loads and weight. It is compatible with standard boost hub spacing and 203 mm post-mount disc brakes. The axle-to-crown measurement aligns with modern downhill geometries and provides sufficient clearance for wide 29” tires.
The fork is best paired with rear shocks in the Factory series or those tuned for eMTB applications, ensuring a balanced suspension feel. It’s important to ensure headset and stem compatibility with the 1.5” tapered steerer tube.
Model Comparisons and Competitive Edge
Compared to similar models like the RockShox BoXXer Ultimate or Öhlins DH38, the Float 40 Factory eMTB stands out for its refined Grip2 damper and eMTB-specific chassis stiffness. While the BoXXer may appeal for its lighter feel, the Float 40 excels in tunability and terrain compliance.
The Öhlins DH38 provides comparable stiffness but lacks the intuitive adjustability of Fox’s user interface. Riders seeking a blend of easy setup and deep adjustability typically favor the Float 40, especially for bike park and downhill race use.
Why Riders Choose the Float 40 Factory eMTB
Durability, adjustability, and compatibility make the Float 40 Factory eMTB a go-to for serious riders. Its stiff chassis absorbs eMTB-specific stress without sacrificing steering precision. The Grip2 damper’s four-way adjustability offers unparalleled suspension customization. Combined with Fox’s reputation for quality, it’s a fork that supports aggressive descending while allowing personalized setup for every ride style.
FAQs
Is the Float 40 Factory eMTB compatible with regular mountain bikes?
While technically installable, it is optimized for eMTB loads and may feel overly stiff on traditional bikes due to its reinforced construction.
What tire sizes fit in the Float 40 Factory eMTB?
It fits up to 2.6” wide 29” tires comfortably, allowing use with aggressive tread patterns for downhill riding.
How often should I service the Float 40 Factory eMTB?
Perform lower leg service every 30–50 riding hours and a full damper/air spring service every 100–125 hours to maintain performance.
Can I use the Float 40 Factory on a dual crown-compatible trail bike?
Yes, but ensure your frame is rated for dual crown forks to avoid stress or damage to the head tube area.
How do I know if the air spring needs more volume spacers?
If you’re using full travel too easily or bottoming out, consider adding volume spacers to increase mid-stroke support and end-stroke progression.
What’s the benefit of the floating axle system?
The floating axle helps align the fork legs precisely with the hub, reducing friction and improving small bump compliance.