⟲ 360° — drag meThe facts.
| Brand | STM |
|---|---|
| Part number | FKW-S130 |
| Type | Slipper clutch (anti-hopping clutch) |
| Anti-hopping mechanism | Patented ball-ramp system |
| Weight saving vs. OEM | approximately 0.7–0.8 kg |
| Fitment | Kawasaki ZX-6R / ZX-6 636 / ZX-6RR (2019–2026) |
| Intended use | Road and track |
DescriptionThe whole story▼
For riders who push the Kawasaki ZX-6R hard into late-braking zones, the risk of a rear-wheel hop or highsider on a missed downshift is never far away. The STM slipper clutch for the ZX-6R / 636 / ZX-6RR (2019-2026), part number FKW-S130, is engineered to eliminate exactly that risk — bringing certified race-grade safety and measurable performance gains to both track days and spirited road riding.
Key Features
- Prevents engine over-rev on downshifts, keeping the rear wheel planted and the chassis stable under hard braking
- Reduces highsider trigger impulse significantly, lowering the risk of a violent crash at high speed — the primary safety case for fitting a slipper clutch
- Patented ball-ramp mechanism governs the anti-hopping function with precision, optimising drive control at high rpm
- Diaphragm spring eliminates pressure-plate wobble, delivering a cleaner, more progressive clutch-lever release feel
- Controlled rear-wheel slide capability for improved corner-entry handling and confidence on track
- Better clutch-closing management through bends prevents the front end from tucking under power pick-up
- Approximately 0.7–0.8 kg weight saving through reduced rotating mass, sharpening throttle response and overall performance of the ZX-6R / 636 / ZX-6RR
Safety and Engineering Rationale
A conventional clutch transmits full engine braking torque directly to the rear tyre during aggressive downshifts. When tyre grip cannot match that torque spike, the rear wheel locks and rebounds — the classic highsider mechanism. STM's ball-ramp slipper system interrupts this cycle by allowing the clutch to partially disengage whenever back-torque exceeds a calibrated threshold. The result is a controlled, graduated transfer of engine braking rather than an abrupt shock load, keeping the chassis settled and the rider in command.
The diaphragm spring design is equally important: it removes the oscillation that standard pressure plates develop at high rpm, giving the lever a consistent, feedback-rich action that makes smooth, fast downshifts more repeatable lap after lap.
Performance Gains
Beyond pure safety, the STM FKW-S130 delivers tangible lap-time benefits for the ZX-6R platform. Shedding approximately 0.7–0.8 kg from the rotating assembly reduces the gyroscopic inertia of the drivetrain, which translates into lighter, more responsive steering and quicker rpm build. The ability to trail-brake deeper and downshift later — with confidence — allows riders to carry greater corner-entry speed without gambling on rear grip.
Fitment and Compatibility
This slipper clutch is a direct-fit replacement for the following Kawasaki models:
- Kawasaki ZX-6R — model years 2019 to 2026
- Kawasaki ZX-6 636 — model years 2019 to 2026
- Kawasaki ZX-6RR — model years 2019 to 2026
Specifications
- Brand: STM
- Part number: FKW-S130
- Type: Slipper clutch (anti-hopping clutch)
- Anti-hopping mechanism: Patented ball-ramp system
- Weight saving: approximately 0.7–0.8 kg vs. OEM assembly
- Fitment: Kawasaki ZX-6R / ZX-6 636 / ZX-6RR (2019–2026)
- Intended use: Road and track
FitmentWhich bikes this fits▼
- Kawasaki ZX-6R / 636 / ZX-6RR (2019–2026)
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