FOX Factory Race Series Quick Switch QS3 Backcountry Ski Kit, Part Number 850-04-007

Fox Quick Switch (QS) coil shocks for trail/crossover applications provide the same performance advantage Fox is known for in the backcountry now. Ride harder with less fatigue without a compromise of durability. Experience a new sense of control on the snow due to velocity and position-sensitive damping technology. Quickly adjust the compression damping with Fox's QS3 to suit snow conditions. Three positions keep the gloves on and the adjustment simple. Focus on riding instead of counting clicks. Fox's position-sensitive damping technology, Rifle Bore, is now applied to the Factory Race Series rear track shock. Spiral grooves inside the shock allow the oil to flow around the main piston, reducing the damping force in the ride zone for a plush feel. The grooves terminate through the final 30% of the travel, forcing oil to flow through the main piston. The final result is a significant increase in bottom-out resistance to cushion hard hits.

The FOX Factory Race Series Quick Switch QS3 Backcountry Ski Kit is designed for trail and crossover snowmobile applications, delivering controlled, confidence-inspiring suspension performance for demanding riding. This kit uses FOX velocity- and position-sensitive damping technology to help reduce rider fatigue while maintaining durability and control across changing snow conditions. Its QS3 three-position compression adjuster allows quick, glove-friendly tuning without counting clicks, so riders can select the preferred compression setting while staying focused on the trail.

The rear track shock features FOX Rifle Bore position-sensitive damping. Spiral grooves inside the shock allow oil to flow around the main piston through the ride zone, creating a plush initial feel. As the shock reaches the final portion of its travel, the grooves terminate and direct oil through the main piston for increased bottom-out resistance during hard impacts. The kit also includes adjustable spring preload, an internal floating piston, high-flow velocity-sensitive damping, and lightweight spring and shock construction.

Features: Fully rebuildable and re-tunable components support long-term serviceability. FOX Ice Scraper Technology (FIST) helps manage snow and ice buildup. One-piece aluminum mounting hardware provides a durable mounting solution. The FOX QS3 compression adjuster offers three simple settings for fast trail-side adjustment. This FOX kit is manufacturer part number 850-04-007 and vendor part number 530-1255.

Fitment: Designed for select Ski-Doo Backcountry models, including the 2023 Backcountry 600R E-TEC 146-inch, 2023 Backcountry 850 E-TEC 146-inch, 2023 Backcountry Sport 600 EFI, 2024 Backcountry X-RS 850 E-TEC 146-inch with 1.6-inch track, 2024 Backcountry X-RS 850 E-TEC 154-inch with 2.0-inch track, 2024 Backcountry X 850 E-TEC 146-inch, 2024 Backcountry Sport 600 EFI 146-inch with 2.0-inch or 1.6-inch track, and 2024 Backcountry Adrenaline 600R E-TEC 146-inch with 1.6-inch or 2.0-inch track. Verify the exact model and track configuration before installation.

Fitment:
2023 Ski-Doo Backcountry 600R E-TEC 146"
2023 Ski-Doo Backcountry 850 E-TEC 146"
2023 Ski-Doo Backcountry Sport 600 EFI
2023 Ski-Doo Backcountry X 850 E-TEC 146"
2023 Ski-Doo Backcountry X-RS 850 E-TEC 146"/1.6"
2023 Ski-Doo Backcountry X-RS 850 E-TEC 154" 2.0
2024 Ski-Doo Backcountry Adrenaline 600R E-TEC 146"/1.6"
2024 Ski-Doo Backcountry Adrenaline 600R E-TEC 146"/2.0"
2024 Ski-Doo Backcountry Adrenaline 850 E-TEC 146"/1.6"
2024 Ski-Doo Backcountry Adrenaline 850 E-TEC 146"/2.0"
2024 Ski-Doo Backcountry Sport 600 EFI 146"/1.6"
2024 Ski-Doo Backcountry Sport 600 EFI 146"/2.0"
2024 Ski-Doo Backcountry X 850 E-TEC 146"
2024 Ski-Doo Backcountry X-RS 850 E-TEC 146" 2.0
2024 Ski-Doo Backcountry X-RS 850 E-TEC 146"/1.6"
2024 Ski-Doo Backcountry X-RS 850 E-TEC 154" 2.0
2024 Ski-Doo Backcountry X-RS 850 E-TEC 154" 2.5
2025 Ski-Doo Backcountry Adrenaline 600R E-TEC 146"/1.6"
2025 Ski-Doo Backcountry Adrenaline 600R E-TEC 146"/2.0"
2025 Ski-Doo Backcountry Adrenaline 850 E-TEC 146"/1.6"
2025 Ski-Doo Backcountry Adrenaline 850 E-TEC 146"/2.0"
2025 Ski-Doo Backcountry Sport 600 EFI 146"/1.6"
2025 Ski-Doo Backcountry Sport 600 EFI 146"/2.0"
2025 Ski-Doo Backcountry X 850 E-TEC 146"
2025 Ski-Doo Backcountry X-RS 850 E-TEC 146" 2.0
2025 Ski-Doo Backcountry X-RS 850 E-TEC 146"/1.5"
2025 Ski-Doo Backcountry X-RS 850 E-TEC 146"/1.6"
2025 Ski-Doo Backcountry X-RS 850 E-TEC 154" 2.0
2025 Ski-Doo Backcountry X-RS 850 E-TEC 154" 2.5
2026 Ski-Doo Backcountry Adrenaline E-TEC 600R 39in. Ski Stance
2026 Ski-Doo Backcountry Adrenaline E-TEC 850 39in. Ski Stance
2026 Ski-Doo Backcountry Sport 600 EFI 39in. Ski Stance
2026 Ski-Doo Backcountry X 850 E-TEC 146" 39in. Ski Stance
2026 Ski-Doo Backcountry X-RS 850 E-TEC 146"/1.5"
2026 Ski-Doo Backcountry X-RS 850 E-TEC 154" 2.0
2026 Ski-Doo Backcountry X-RS 850 E-TEC 154" 2.5