Primary Drive Clutch Spring (140-300) for Polaris Patriot 9R (Short Track / Trail) & Patriot Boost (Long Track / Mountain) // SKU: 05-140-300

SKU: 05-140-300

Spring Rate: 140 lb Initial Load / 300 lb Finish Load

Primary Applications: Polaris Patriot RMK Boost (Mountain / Deep Powder) & Polaris Patriot 9R (Short Track / Trail).

Fine-tune your clutch engagement and maintain consistent peak shift RPM under heavy power loads with the Bikeman Performance 140-300 Primary Drive Clutch Spring. The primary clutch spring controls the RPM threshold at which drive sheaves engage the belt, as well as the progressive resistance against your primary clutch weights as the clutch shifts out through its powerband.

Featuring a 140 lb initial engagement load and a 300 lb finish load, this spring profile serves two distinct high-performance setups:

• Patriot RMK Boost (Mountain): Delivers smooth, predictable engagement that prevents track trenching in deep powder off the line, while the 300 lb finish load holds target operating RPM without over-revving or fading during long, steep turbo pulls.
• Patriot 9R (Trail / Short Track): Provides crisp, immediate throttle pickup out of trail corners while providing the ideal resistance to hold the high-revving 899cc big-bore twin at its peak horsepower sweet spot across hard-pack trails and lakes.

Manufactured from premium shot-peened high-tensile alloy spring steel, this primary spring is engineered to withstand extreme under-hood operating temperatures, severe vibration, and rapid compression cycles without sagging, binding, or losing its rate profile over time.

Key Performance Features

• Dual-Calibrated Performance Profile: Engineered specifically for the elevation and power delivery of deep-snow Patriot RMK Boost sleds, as well as corner-to-corner trail acceleration on short-track Patriot 9R models.
• 140-300 Spring Rate Curve: The 140 lb initial rate ensures smooth, controlled clutch engagement without abrupt jerking or soft-snow trenching; the 300 lb finish load holds target RPM locked in at wide-open throttle.
• Eliminates RPM Fade: Resists heat-soak and rate fatigue under continuous full-throttle pulls, keeping your shift-out consistent from morning to late afternoon.
• Shot-Peened High-Tensile Steel: Premium high-stress alloy construction prevents spring collapse and maintains factory spring height and load ratings across multiple seasons.

Vehicle Fitment & Compatibility

• Polaris Patriot RMK Boost (Mountain Chassis Only — 2022+):
  • PRO-RMK Boost (155, 163, 165)
  • RMK Khaos Boost (146, 155, 163, 165)
• Polaris Patriot 9R (Trail & Short Track Models — 2023+):
  • Switchback Assault 9R (146 with trail lug tracks)
  • Indy XCR 9R / VR1 9R trail configurations
• Fitment Exclusions:
  • Does NOT fit Trail Boost models (Indy VR1 Boost, Switchback Assault Boost).
  • Does NOT fit Patriot 9R Mountain RMK models running 2.0"+ lug tracks (requires SKU: 05-140-330).