Len Performance Front Track (Center) Shock, Polaris Indy VR1 / XC / XCR / Adventure Matryx 2021–2026 (54-50003F)
Len Performance Front Track (Center) Shock, Polaris Indy VR1 / XC / XCR / Adventure Matryx 2021–2026 (54-50003F)
Len Performance
FREE ANCHORAGE PICKUP
Most orders are ready within 24 hours. Supplier-order exceptions are confirmed by email; freight to A2D is included in the product price. Need same-day pickup? Call 907-306-3062.
Shipping options and charges are shown at checkout. Shipping information.
CHECK YOUR FITMENT
Confirm your machine’s year, model, submodel, and the selected size or option before ordering. Need help? Contact the A2D team.
Product details
Len Performance LS4-50003F rebuildable front track shock, also called the center shock, for the rear suspension on the 2021–2026 Polaris Matryx Indy VR1, XC, XCR and Adventure 128 / 129 / 136 / 137 in 650, 850, Patriot Boost and Patriot 9R. It replaces the factory front track shock with a coil-over reservoir shock. At $520.95 each, it is A2D's value pick for a rebuildable, adjustable reservoir front track shock: clicker adjustment, a reservoir and a serviceable design without the cost of a race-level shock.
The front track shock controls how the skid loads under acceleration, how the sled transfers weight and how much ski pressure you keep when you get on the throttle. Being able to adjust it, rather than living with fixed factory valving, is the single biggest change most riders feel in the rear suspension. 5-click compression adjustment and threaded preload rings let it be set for rider weight and trail conditions.
Fitment. Sold each. Pairs with the Len Performance 54-50003R rear track shock for a complete rear suspension (Len Performance sells the pair as kit LS4-50003K). Matching ski shock: 54-50000. Chassis: Polaris Matryx.
Fitment list (Len Performance year/model lookup)
- Indy: 2021-2023 650 Indy VR1 129 Matryx; 2021-2026 650 Indy VR1 137 Matryx; 2021-2023 850 Indy VR1 129 Matryx; 2021-2026 850 Indy VR1 137 Matryx; 2022-2024 650 Indy XC 129 Matryx; 2022-2026 650 Indy XC 137 Matryx; 2022-2025 650 Indy XCR 128; 2022-2025 650 Indy XCR 136 Matryx; 2022-2023 850 Indy Adventure 137 Matryx; 2022-2024 850 Indy XC 129 Matryx; 2022-2026 850 Indy XC 137 Matryx; 2022-2025 850 Indy XCR 128 Matryx; 2022-2025 850 Indy XCR 136 Matryx; 2023 Patriot Boost Indy VR1 129 Matryx; 2023 Patriot Boost Indy VR1 137 Matryx; 2025 Patriot 9R Indy XCR 128 Matryx; 2025 Patriot 9R Indy XCR 136 Matryx; 2026 650 Indy XCR 129; 2026 650 Indy XCR 137; 2026 Patriot 9R Indy XCR 129; 2026 Patriot 9R Indy XCR 137
Features
- 5-click compression adjustment, tool-free.
- Aluminum reservoir shock: the remote-style reservoir keeps oil temperature down and damping consistent on long pulls.
- Fully rebuildable, serviceable shock. Len Performance rebuild kits and replacement parts are available.
- Hardened chromoly shaft for strength and seal life.
- Forged aluminum eyelet heads with premium steel and NBR bushings.
- Powder-coated spring resists corrosion and holds rate in cold, wet conditions.
- Threaded shock body with anodized dual-ring locking preload adjusters: set sag once and it stays set.
- Sold each.
Specifications
| Part number | 54-50003F (Len Performance LS4-50003F) |
| OEM part number replaced | 7045430 (per distributor listings) |
| Shock location | Front track shock / center shock (rear suspension) |
| Chassis / platform | Polaris Matryx |
| Adjustments | Compression (5), plus threaded spring preload |
| Length, extended | 329 mm / 12.96 in |
| Length, compressed | 232 mm / 9.14 in |
| Stroke | 97 mm / 3.82 in |
| Spring | Powder-coated coil spring included, 72 mm / 2.84 in diameter |
| Top eyelet | 14.5 mm ID x 42.7 mm wide (0.58 in x 1.68 in) |
| Bottom eyelet | 18 mm ID x 29.5 mm wide (0.71 in x 1.17 in) |
| Weight | 5.20 lb |
| Includes | One shock |
| Rebuild kit | Len Performance rebuild kits available; call to confirm the kit number for this shock |
| Sold | Each |
Ordering and installation. Sold each. Ships from stock at our Anchorage shop, or from our distributor's Boise, Idaho warehouse when not on the shelf. In-store pickup is available at checkout. Installation and shock setup are available at A2D Motorsports; call (907) 306-3062 to schedule. Len Performance rebuild kits are available, so the shock can be serviced or re-valved rather than replaced.