The Fox Float 40 Factory eMTB suspension fork is a premium component engineered specifically for the demanding conditions of electric mountain biking. Built with advanced damping technologies, robust structural integrity, and compatibility with high-torque eMTB frames, this fork delivers unparalleled performance on descents and technical trails. This article offers a deep dive into the installation, tuning, troubleshooting, customization, and compatibility of the Float 40 Factory eMTB, ensuring precise setup and sustained optimal performance.

Tools Required

• 6 mm and 5 mm Allen keys [paid link]
• Torque wrench [paid link] (2–15 Nm range)
• Shock pump with bleed valve
• Crown race setter
• Star nut setter (if using alloy steerer)
• Caliper or rotor alignment tool
• Suspension oil and service-specific tools (for maintenance)

Installation Guide for the Float 40 Factory eMTB

Proper installation begins with preparing the fork for the head tube and brake system. This fork uses a tapered steerer and is compatible with both traditional and integrated headsets. Before cutting the steerer, riders should test-fit the fork and confirm the cockpit height.

Ensure the crown race is seated evenly using the correct setter. Install the fork into the frame, tighten the stem bolts lightly, and set headset preload using the top cap. Once aligned, torque the stem bolts to specification. The front brake caliper mounts directly to the 203 mm post mount; adaptors are only required for larger rotors. Brake hoses must be routed externally and secured without impeding fork travel.

Adjusting Air Spring and Volume Spacers

The Float 40 Factory eMTB utilizes Fox’s EVOL air spring, which supports fine-tuned air pressure and spring curve adjustment.

Riders should begin by setting the sag at 15–20% of fork travel, using the shock pump. The factory-recommended pressure chart offers a useful baseline, but adjustments may be needed based on terrain and rider weight. For riders seeking more mid-stroke support or bottom-out resistance, volume spacers can be added. Each spacer changes the spring progression, allowing aggressive riders to customize performance without compromising small-bump sensitivity.

Fine-Tuning the GRIP2 Damper

The GRIP2 damper featured in the Float 40 Factory provides high- and low-speed compression and rebound adjustments. Low-speed compression controls chassis stability under slow suspension movements like braking or cornering. High-speed compression manages impacts from rocks or jumps.

To start, set all adjusters to the middle of their range and test ride on familiar terrain. From there, adjust low-speed rebound to achieve a controlled return without kickback. High-speed rebound should be tuned to prevent excessive bounce on repeated hits. Compression settings should be adapted based on terrain roughness and rider speed, maintaining traction without causing harshness.

Routine Maintenance Schedule

Consistent maintenance of the Float 40 Factory eMTB ensures smooth operation and extends fork life. Dust wipers and bath oil should be inspected every 30 riding hours. Full lower leg service, including cleaning and re-lubricating the foam rings, should occur every 50 hours. The damper and air spring should be serviced every 125–200 hours depending on conditions.

Before each ride, check air pressure, inspect stanchions for wear or oil, and ensure all bolts are torqued correctly. Post-ride, clean the fork with a soft cloth and mild soap, avoiding high-pressure washing that could force contaminants past seals.

Common Setup Issues and Their Solutions

Improper sag setup often leads to harsh riding characteristics or underutilized travel. Ensure sag is correctly measured while wearing full gear. If the fork feels harsh or too soft, confirm air pressure matches the desired setting and reassess volume spacers.

Riders sometimes misinterpret damper clicks; count from fully closed (clockwise) to ensure accurate adjustments. Brake rub is another common concern. Realign the caliper after proper torque, and verify rotor trueness. Excessive noise during compression may indicate insufficient oil or a need for service.

Performance Customization and Rider Preferences

The Float 40 Factory allows extensive customization beyond standard tuning. Fox offers stiffer or lighter spring curves with optional air shaft kits. Compression tune shims inside the GRIP2 damper can be altered for specific trail applications, though this requires technical expertise.

For eMTB riders focusing on enduro-style trails, faster rebound paired with firm compression enhances control. Downhill-oriented riders often prefer slower rebound and increased volume spacers for bottom-out resistance. Riders should experiment in controlled environments to match setup to style.

Comparing the Float 40 Factory eMTB with Similar Models

The primary competition includes the RockShox ZEB Ultimate and Öhlins RXF38 m.2. Compared to the ZEB, the Float 40 offers more refined adjustability via GRIP2 and better small-bump compliance. The Öhlins fork provides similar stiffness but lacks the same level of aftermarket tuning support.

Fox’s proprietary Kashima coating on the stanchions reduces friction better than most competitors, especially under load. The Float 40 Factory also weighs less than its dual-crown counterparts, making it attractive for aggressive trail use without committing to full downhill setups.

Compatibility with Drivetrain and Chassis Components

Designed explicitly for eMTBs, the Float 40 Factory is structurally optimized to handle additional chassis weight and motor torque. It fits frames with tapered head tubes and is commonly paired with 29” or mixed-wheel setups.

The fork integrates seamlessly with eMTB drivetrains, although care must be taken to match rotor size and brake mounts. The axle system is 20 x 110 mm Boost, which is compatible with most modern eMTB hubs. Ensure that wheel and rotor selections maintain proper clearance and structural alignment.

Conclusion

The Float 40 Factory eMTB represents a peak in eMTB suspension design. Its blend of adjustability, stiffness, and engineering sophistication allows riders to tailor performance precisely to their needs. With correct installation, ongoing maintenance, and personalized tuning, this fork ensures reliability and control across the most technical terrains. Whether descending steep alpine lines or navigating root-laced singletrack, the Float 40 Factory delivers elite-level performance and versatility for today’s electric mountain biking demands.