The Float 40 Factory eMTB from Fox is designed for aggressive electric mountain biking, offering superior damping, stiffness, and adjustability for the most demanding trails. Built to endure the added weight and torque of eMTBs, this fork integrates advanced technologies like GRIP2 damper, FLOAT EVOL air spring, and Kashima-coated stanchions. This guide provides a comprehensive overview of its installation, fine-tuning, maintenance, troubleshooting, customization, and compatibility to help riders extract maximum comfort and performance.
Tools Required
- Torque wrench [paid link] with appropriate sockets
- Allen wrenches [paid link] (4mm to 8mm)
- Crown race setting tool
- Star nut installation tool or compression plug (for carbon steerer)
- Suspension pump
- Shock oil (recommended weight)
- Isopropyl alcohol and clean rags
Installation Guide
Proper installation ensures both safety and optimum fork performance. Begin by checking steerer tube compatibility with your frame’s head tube. The Float 40 Factory comes with a tapered steerer and is intended for triple clamp setups.
Ensure headset bearings are correctly preloaded using either a star nut or a compression plug. Tighten stem bolts evenly, using a torque wrench [paid link] to avoid overtightening. Secure the fork axle into the front hub, confirming that the pinch bolts are torqued to spec (typically 5–6 Nm). Finally, install the brake caliper and align it to prevent rotor rub. Ensure brake hose routing avoids interference with the fork’s travel.
Initial Setup and Air Spring Adjustment
The FLOAT EVOL air spring allows for precise customization of the spring curve. Begin by checking the rider weight and refer to Fox’s pressure chart as a starting point. Inflate the fork to the recommended pressure using a shock pump. Allow the fork to “equalize” by cycling it through 25% of its travel, then recheck and fine-tune the pressure.
Adjust sag using an o-ring or zip tie on the stanchion. For trail and enduro eMTB riders, 15–20% sag is a common baseline. The EVOL chamber ensures initial sensitivity and small bump compliance, which is essential for comfort.
GRIP2 Damper Tuning
The GRIP2 damper features high-speed and low-speed compression and rebound adjustments. Begin tuning with factory-recommended settings:
- High-Speed Compression: Controls harsh hits and bottom-out resistance.
- Low-Speed Compression: Affects ride feel during slow compressions, like pedaling or braking.
- High-Speed Rebound: Governs fork recovery after rapid impacts.
- Low-Speed Rebound: Fine-tunes fork behavior during general trail riding.
Turn each adjuster clockwise to increase damping (firmer) and counter-clockwise to decrease it (softer). Make incremental adjustments, noting trail feedback and changes in ride comfort.
Regular Maintenance Schedule
Consistent maintenance prolongs fork life and preserves performance. Key maintenance intervals include:
- Every 30 hours: Clean stanchions, inspect dust wipers, and check air pressure.
- Every 50 hours: Replace bath oil, clean air spring, and lubricate seals.
- Every 125 hours or annually: Full damper and air spring rebuild, including seal replacement.
Use only Fox-approved oils and grease to avoid damaging internal components. Always depressurize the fork before disassembly.
Troubleshooting Common Issues
If the fork feels harsh or unresponsive, air pressure may be too high, or rebound damping may be too slow. Excessive dive under braking can indicate too little low-speed compression or insufficient air pressure. Bottoming out frequently suggests the need to increase air pressure or add volume spacers to the air chamber.
Noises such as knocking or slurping during compression can result from insufficient oil levels or air spring seal wear. Leaks around the seals or damper suggest service is overdue or internal damage.
Performance Customization and Tuning
For riders seeking enhanced comfort or performance characteristics, several tuning options are available.
Install volume spacers to adjust progressivity. Adding spacers increases bottom-out resistance, while removing them softens the end-stroke. Swap rebound and compression shim stacks only if experienced or under supervision, as improper tuning can damage the damper or compromise safety.
Some riders prefer softer settings for comfort during long descents or technical climbs, while others opt for firmer damping in bike park conditions. Record baseline settings and test in similar conditions for accurate comparison.
Compatibility Considerations
The Float 40 Factory eMTB is optimized for 29” wheels and 110mm Boost spacing. It is not cross-compatible with standard mountain bike forks due to its reinforced chassis and eMTB-specific valving.
The fork pairs best with Fox rear shocks featuring EVOL air sleeves and GRIP2 or X2 dampers for consistent ride feel. Ensure brake mounts match the fork’s post-mount 203mm standard. Use only 1.5” tapered headsets, and confirm that axle-to-crown height fits your bike’s geometry.
Float 40 Factory eMTB vs. Comparable Models
When compared to the RockShox Boxxer Ultimate, the Float 40 Factory delivers greater small bump compliance and adjustability through its GRIP2 damper. Unlike the Boxxer, the Fox fork uses a more progressive air spring design, offering a wider tuning window for heavier eMTB builds.
Against the Öhlins DH38, the Float 40 weighs slightly less and provides better out-of-the-box comfort tuning. However, Öhlins may offer a plusher midstroke feel, depending on rider preferences.
Long-Term Comfort Optimization Tips
To maintain consistent ride comfort over time:
- Routinely check sag and adjust for load variations, such as gear or battery changes.
- Clean and lubricate stanchions after every ride to minimize stiction.
- Store the bike vertically or hang it to keep oil evenly distributed inside the fork.
- Avoid jet-washing seals directly to prevent contamination.
Comfort isn’t just about plushness—it’s about consistent performance across various terrain and conditions. Regular tuning and mindful riding habits enhance the experience.
FAQs
Q1: Can I use the Float 40 Factory eMTB on a regular mountain bike?
No, this fork is specifically built for eMTBs due to its reinforced crown and chassis, which are designed to handle higher loads.
Q2: What is the maximum tire size compatible with the Float 40 Factory?
It supports up to 29×2.6” tires, but always check clearance after inflation and under compression.
Q3: How do I know if I need to service the damper?
If damping becomes inconsistent or feels spongy, or if there’s oil leaking near the rebound knob, a damper service is due.
Q4: Does this fork come with volume spacers pre-installed?
Yes, but the number varies. You can add or remove spacers to fine-tune the air spring’s progressivity.
Q5: Is the Kashima coating purely aesthetic?
No, Kashima reduces friction and enhances durability by providing a harder, low-stiction surface.
Q6: Can I upgrade to a coil spring on the Float 40 Factory eMTB?
No, the FLOAT 40 Factory is air-spring only. For coil conversion, other models like the Fox 40 Performance Elite Coil must be considered.