The Fox 38 Rhythm suspension fork is purpose-built for aggressive trail riding and enduro-level terrain, offering an ideal balance of stiffness, performance, and serviceability. Positioned as a more affordable option in the 38 series, the Rhythm version prioritizes performance without unnecessary features that inflate cost or complexity. This guide offers an in-depth look at the installation, setup, maintenance, and tuning of the 38 Rhythm, along with a comparison to other Fox forks in the same series to help riders make informed decisions.
Tools Required
- 6mm and 5mm hex keys [paid link]
- Torque wrench [paid link] with Nm settings
- Crown race setting tool
- Suspension pump
- Fox Float fluid or recommended suspension lubricant
- Torque cap-compatible front wheel (for specific hub designs)
- Caliper alignment tool (optional for brake installation)
Installation Process
Installing the Fox 38 Rhythm requires attention to detail due to its robust chassis and large stanchion design. Start by ensuring the steerer tube is cut to the appropriate length for your frame and headset stack. Use a crown race setter to install the correct race, and insert the fork into the frame’s head tube.
Ensure headset bearings are clean and greased before securing the stem and spacers. Torque stem bolts to manufacturer specifications, typically 5-6 Nm. When aligning the brake caliper, use the appropriate adapter for your rotor size—commonly 180mm or 203mm. Align the caliper precisely to avoid rotor rub during hard braking.
The thru-axle must be torqued correctly to prevent unwanted flex under load. Be sure to use a torque wrench [paid link] to tighten the axle to Fox’s recommended 19.5 Nm.
Initial Suspension Setup
Tuning the Fox 38 Rhythm begins with setting the correct air pressure according to rider weight. Fox provides an air pressure guide printed on the fork leg. Adjust the air spring with a shock pump, aiming for 20–30% sag, which can be measured using the fork’s sag indicator o-rings.
Rebound damping is adjusted via the red knob on the lower right leg. Start in the middle setting and make incremental changes based on trail feel—faster rebound for technical terrain and slower rebound for smoother flow trails.
The GRIP damper used in the Rhythm model offers simplified tuning through a single compression dial. Turn clockwise to increase compression damping for more support in rough terrain or counter-clockwise to soften the ride.
Routine Maintenance Procedures
To maintain optimal performance, inspect the 38 Rhythm every 25 hours of riding. Begin by cleaning the stanchions and inspecting the wiper seals for dirt or oil leakage. Apply a small amount of Fox Float Fluid around the seals to maintain smooth movement.
Every 50 hours, perform a lower leg service. This involves removing the lowers, cleaning internal components, replacing foam rings and bath oil, and reassembling using fresh Float Fluid. Fox recommends 20cc of fluid per leg for this model.
At 125 hours, a full damper and air spring service is required. This should be done by a qualified mechanic unless you have experience with pressurized suspension components.
Troubleshooting Common Issues
A noisy fork during compression may indicate dry seals or insufficient bath oil. Regular lubrication resolves this issue. If the fork feels harsh or fails to use full travel, check air pressure and verify that the negative air spring is not over-pressurized due to improper equalization during inflation.
A stuck-through axle or difficulty removing the front wheel often results from overtightening or grit contamination—clean the axle and dropout interfaces thoroughly and lightly grease the axle.
Excessive fork dive on braking or cornering typically relates to low air pressure or inadequate compression damping. Revisit your sag setup and add compression clicks to firm the fork’s mid-stroke support.
Customization and Performance Optimization
Although the 38 Rhythm lacks high-speed compression adjustments found in the Factory models, riders can fine-tune performance using volume spacers. These tokens adjust the spring curve by reducing air chamber volume, increasing end-stroke progression.
Aggressive riders can add volume spacers to prevent bottom-out events on big hits, while lighter or flow-focused riders might prefer fewer spacers for a plusher feel.
Handlebar-mounted remote lockouts are not available for the Rhythm variant, but its simple compression dial is durable and intuitive for on-trail adjustments.
Comparative Overview with Other Fox Forks
When compared to the 38 Performance and Factory models, the Rhythm maintains much of the structural integrity but forgoes features like the FIT4 damper and Kashima coating. This makes it slightly heavier but also more cost-effective.
While the GRIP damper in the Rhythm is less tunable than the GRIP2 found in the Factory series, it remains extremely capable for most enduro and trail riders. The Rhythm is ideal for riders prioritizing stiffness and simplicity over infinite adjustability.
Compatibility with Drivetrain and Frame Components
The 38 Rhythm is designed for modern trail and enduro bikes and supports 29″ or 27.5″ wheels with Boost 110 spacing. It’s compatible with both SRAM and Shimano front brake systems and uses a post-mount design for rotors.
Ensure your head tube accommodates a tapered steerer (1.5″ to 1-1/8″) and verify frame clearance for up to 180mm of travel, depending on the Rhythm variant.
The fork is torque cap-compatible, enhancing front-end stiffness when paired with matching hubs but works seamlessly with standard hubs as well.
Conclusion
The Fox 38 Rhythm strikes a strong balance between affordability and performance, making it a worthy consideration for riders focused on rugged terrain and demanding descents. Its simplified damping system, robust chassis, and easy maintenance requirements make it a practical and powerful option for everyday riders and weekend warriors alike. For those seeking a fork that blends stiffness, simplicity, and strength without compromising core performance, the 38 Rhythm delivers consistently across the board.