MRP Noken High Volume Air Cap for Fox 38 WB-24-2221

Engineered to expand your Fox 38's air-spring capacity, the MRP Noken delivers a measurable increase in volume that softens the compression curve and flattens the mid-stroke resistance. The result is a more progressive, coil-like feel that resists harsh bottom-out forces while maintaining responsive mid-range support—ideal for riders seeking plush compliance without sacrificing control.

The Noken expands your Fox 38's air chamber to deliver volume equivalent to 1.5 standard spacers, fundamentally reshaping your fork's spring character. This upgrade solves the tuning puzzle many riders face: achieving initial suppleness, mid-stroke support, and full-travel utilization simultaneously. By increasing air volume above the crown, the Noken creates the progressive curve needed to dial in that critical balance without sacrificing performance across the entire stroke.

Modern air-spring tuning prioritizes negative volume to enhance small-bump sensitivity, but this design choice often compromises positive volume—leaving riders unable to fully exploit their fork's travel range as the spring ramps aggressively near end-stroke. The Noken recalibrates this equation by restoring positive chamber capacity, allowing you to maintain that refined initial sensitivity while preserving access to the complete travel spectrum without excessive progression.

The Noken eliminates the traditional compromise inherent in modern air-spring design. By augmenting positive volume, it preserves the small-bump sensitivity and mid-stroke support that larger negative chambers provide, while simultaneously restoring full-travel accessibility. You gain the compliance benefits of aggressive negative tuning without surrendering the progressive curve needed to confidently use every millimeter of your Fox 38's stroke.

WARNING:

The Noken is 10-13mm taller than standard damper control knobs, so it’s important to confirm downtube clearance before installation. Review our clearance guidelines or download our 3D printable files (Zeb/RS 35 and 38) to help with this step. Additionally, you can use the new Riser Crown Race to create the needed clearance, available in HighRise (+10mm) or LowRise (+5mm) options.

FOX 38

The graph above illustrates the change in spring curve with the Noken vs. the stock 38 170mm configuration (with includes two volume spacers).