Len Performance Rear Track Shock, Polaris Switchback Assault 144 / 146, Switchback XCR & SKS 146 2017–2026 (54-50000R)
Len Performance Rear Track Shock, Polaris Switchback Assault 144 / 146, Switchback XCR & SKS 146 2017–2026 (54-50000R)
Len Performance
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Product details
Len Performance LS4-50000R rebuildable rear track shock for the rear suspension on the 2017–2021 AXYS Switchback Assault 144 (600 / 800 / 850), 2018–2021 AXYS SKS 146 (800 / 850), 2019–2021 850 Switchback XCR and the 2021–2026 Matryx Switchback Assault 146 (650, 850, Patriot 9R and Patriot Boost). It replaces the factory rear track shock with a reservoir shock that has 5-click compression adjustment. At $394.95 each, it is A2D's value pick for a rebuildable, adjustable reservoir rear track shock: clicker adjustment, a reservoir and a serviceable design without the cost of a race-level shock.
The rear track shock sets how the skid handles big hits, deep-snow re-entries and bottoming with gear on the tunnel. This is a springless unit that works with the factory rear torsion springs, so it drops in without changing the rest of the skid.
Fitment. Sold each. Pairs with the Len Performance 54-50000F front track shock for a complete rear suspension (Len Performance sells the pair as kit LS4-50000K). Matching ski shock: 54-50000 (Switchback Assault / XCR) or 54-50002 (SKS). Chassis: Polaris AXYS (2017–2021) and Matryx (2021–2026).
Fitment list (Len Performance year/model lookup)
- Switchback: 2017-2021 600 Switchback Assault AXYS 144; 2017-2020 800 Switchback Assault AXYS 144; 2019-2021 850 Switchback Assault AXYS 144; 2019-2021 850 Switchback XCR; 2021-2026 650 Switchback Assault 146 Matryx; 2021-2026 850 Switchback Assault 146 Matryx; 2023-2026 Patriot Boost Switchback Assault 146 Matryx; 2025 Patriot 9R Switchback Assault 146 Matryx
- SKS: 2018-2020 800 SKS AXYS 146; 2019-2021 850 SKS AXYS 146
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.
- Sold each.
Specifications
| Part number | 54-50000R (Len Performance LS4-50000R) |
| OEM part number replaced | 7044379 (per distributor listings) |
| Shock location | Rear track shock (rear suspension) |
| Chassis / platform | Polaris AXYS / Matryx |
| Adjustments | Compression (5) |
| Length, extended | 490 mm / 19.3 in |
| Length, compressed | 327 mm / 12.9 in |
| Stroke | 163 mm / 6.4 in |
| Spring | None (uses the factory torsion springs) |
| Top eyelet | 17.7 mm ID x 29.3 mm wide (0.7 in x 1.2 in) |
| Bottom eyelet | 15.9 mm ID x 29.2 mm wide (0.6 in x 1.1 in) |
| Weight | 3.55 lb (6 lb shipping) |
| Includes | One shock |
| Rebuild kit | 54-00003 (Len LSR-00003), per Dennis Kirk |
| 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.