The facts.
| Brand | STM |
|---|---|
| Part number | FMW-S050 |
| Type | Slipper clutch (anti-hopping clutch) |
| Fitment | MV Agusta F3 800 (2013–2026) |
| Anti-hopping mechanism | Patented ball-ramp system |
| Spring type | Diaphragm spring |
| Approximate weight saving | ~0.7–0.8 kg versus OEM assembly |
DescriptionThe whole story▼
If you ride the MV Agusta F3 800 hard on the road or take it to the track on weekends, the STM slipper clutch FMW-S050 is one of the most practical and rewarding upgrades you can make. It tames the engine's braking force under hard downshifts, keeps the rear wheel planted, and reduces rider fatigue — all while shaving meaningful rotating mass from the drivetrain.
Key Features
- Prevents engine over-rev on downshifts for a smooth, composed ride in traffic and on circuit alike
- Reduces rear wheel hop under hard braking, improving traction and stability in real-world riding conditions
- Lowers the trigger impulse of a highside, adding a genuine safety margin at speed
- Allows controlled rear wheel slide for confidence-inspiring cornering and better feel
- Improved clutch closure control through bends prevents the front end from tucking mid-corner
- Diaphragm spring design gives a cleaner lever release and eliminates pressure-plate flutter
- Patented ball-ramp mechanism manages the anti-hopping function precisely across the rev range
- Approximate weight saving of 0.7–0.8 kg over the standard clutch assembly by reducing rotating mass
Everyday Usability Meets Track Performance
It is easy to assume slipper clutches are purely circuit hardware, but the STM FMW-S050 earns its keep every time you filter through traffic or execute a late, aggressive downshift on a twisting road. The diaphragm spring smooths out lever feel so the clutch engages progressively rather than snapping shut, which makes slow-speed manoeuvring noticeably easier. On track, the ball-ramp anti-hopping system takes over, metering the slip precisely so you can trail the brake deep into a corner without the rear stepping wide or a highside threatening your race.
Construction and Engineering
STM has designed this unit to replace the entire OEM clutch assembly on the F3 800, not merely supplement it. The patented ball-ramp geometry is the heart of the system: as rear-wheel overrun tries to spin the clutch basket faster than the engine, the ramps separate the pressure plate just enough to allow slip, then reapply clamping force the instant drive is restored. The result is predictable, repeatable behaviour that riders can learn and exploit. The weight reduction of approximately 0.7–0.8 kg comes from a combination of lighter materials and a more compact design, lowering rotational inertia so the engine revs more freely and responds more crisply to throttle inputs — a tangible difference on the F3 800's already eager inline-three.
Fitment and Compatibility
The STM anti-hopping clutch FMW-S050 is a direct fitment for the MV Agusta F3 800 across all model years from 2013 through 2026. No modifications to the engine casings or gearbox are required for installation.
Specifications
- Brand: STM
- Part number: FMW-S050
- Type: Slipper clutch (anti-hopping clutch)
- Fitment: MV Agusta F3 800 (2013–2026)
- Anti-hopping mechanism: Patented ball-ramp system
- Spring type: Diaphragm spring
- Approximate weight saving: 0.7–0.8 kg versus OEM assembly
FitmentWhich bikes this fits▼
- MV Agusta F3 800 (2013–2026)
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