Sirris F43 CMX Fork: Arctic Leopard XE Pro S / Enduro
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- Lead Time: Ships in 5 days
Upgrade your Arctic Leopard XE Pro S or Enduro with the Sirris F43 CMX Fork. Built around Sirris' oversized, race-proven F43 chassis, this 220mm travel fork combines 43mm stanchions with the CMX (Compact Motocross) closed-cartridge damping system for increased front-end control, stability, and durability during aggressive off-road riding.
The Arctic Leopard version is specifically configured for the XE Pro S and Enduro with a drop clamp, dedicated wheel spacers, and 220mm brake rotor bracket for proper fitment.
Important: This fork fits the Arctic Leopard XE Pro S and Enduro only. The Arctic Leopard XE Pro R requires a different F43 fork due to its brake bracket configuration and is available as a separate product.
140 lbs - 180 lbs (Medium = 4.0/3.6 springs)
180 lbs - 220 lbs (Heavy = 4.0/4.0 springs)
Fork spring rates listed above are left side/right side.
Sirris F43 CMX Fork Features
- 220mm Travel — provides substantial suspension travel for aggressive trail riding, jumps, rough terrain, and higher-speed riding
- Oversized 43mm Stanchions — high-tensile steel construction with hard chrome finish for increased stiffness, durability, and steering precision
- CMX Closed-Cartridge Damping — symmetrical, adjustable closed cartridges with high-flow pistons and fully tunable compression and rebound valving
- Tool-Free Compression Adjustment — allows quick compression changes without additional tools
- Hydraulic Bottom-Out Control — hydraulic bump stop helps soften hard landings while allowing maximum usable stroke
- 178mm Fork Spacing — provides additional clearance and flexibility for dirt and street tire setups
- Arctic Leopard Drop Clamp — billet aluminum drop clamp increases total fork length to 800mm
- Ultra-Stiff Race-Grade Axle — designed to improve steering precision, front-end feel, and stability
- Replaceable Brake Caliper Bracket — allows additional flexibility for future brake and wheel upgrades
- 220mm Brake Rotor Bracket Included — configured specifically for the Arctic Leopard XE Pro S / Enduro application
- Arctic Leopard Wheel Spacers Included — model-specific spacers are included for proper wheel fitment
- Motorcycle-Style Top Cap — allows more consistent control over steering bearing tension
Arctic Leopard Compatibility
This Sirris F43 CMX Fork model is designed specifically for the Arctic Leopard XE Pro S and Enduro only. The fork includes the required Arctic Leopard wheel spacers and 220mm rotor brake bracket.
The fork uses a 4-bolt direct mount stem. Later XE Pro S models are equipped with a compatible direct mount stem. Some earlier XE Pro S models may require a direct mount stem upgrade, so we recommend checking your bike before installation.
The Arctic Leopard XE Pro R uses a different Sirris F43 fork model because of its brake bracket configuration. Shop here for the Sirris F43 CMX Fork: Arctic Leopard XE Pro R.
Complete Arctic Leopard Suspension Setup
For a balanced front and rear suspension upgrade, pair the F43 CMX Fork with the Sirris R38 Rear Shock for the Arctic Leopard XE Pro S / Enduro / R. The R38 rear shock requires the matching TMB Linkage for Sirris R38 and cannot be used with the factory Arctic Leopard linkage.
F43 CMX Fork Specifications
| Architecture | Upside down fork |
| Travel | 220mm |
| Free Length | 775mm (800mm total length with drop clamp) |
| Fork Spacing | 178mm |
| Fork Weight | 4 kg per leg |
| Stanchions | 43mm high-tensile steel with hard chrome |
| Outer Tubes | Seamless 7050 aluminum, Type III hard anodized |
| Drop Outs | 6061 aluminum, Type II anodized |
| Brake Mounting | Designed for 220mm rotor; 220mm brake bracket included |
| Triple Clamps | Drop clamp, billet 6061 aluminum, Type II anodized, black |
| Steer Tube | Seamless 7050 aluminum, Type II anodized |
| Stem Mount | 4-bolt direct mount stem only |
| Damping | CMX symmetrical adjustable closed cartridge with spring-backed modified IFP |
| Adjusters | External tool-free compression; adjustable rebound |
| Seals | NOK MX seals |
| Bushings | Daido MX bushings |
| Guards | High-impact PP, 210° wraparound |
Fork Tuning & Rider Weight
Sirris offers two spring configurations based on rider weight. Listed rider weights are body weight without riding gear; approximately 15 lbs of riding gear is factored into the recommended ranges. The weight of major upgrades such as batteries and controllers should also be considered when selecting a spring rate.
- Medium: 140-180 lbs — 4.0/3.6 fork springs
- Heavy: 180-220 lbs — 4.0/4.0 fork springs
Riders near the upper end of a weight range or aggressive riders may benefit from moving to the heavier spring configuration and adjusting preload to achieve proper sag.
| FORK Recommendations | Medium | Heavy |
|---|---|---|
| Rider Weight (lbs) (No Gear) | 140-180 | 180-220 |
| Spring Rate (N/mm) | 4.0/3.6 | 4.0/4.0 |
| Fork Height in Upper Clamp (mm) | 5 | 5 |
| Compression Setting | 16 | 14 |
| Rebound Setting | 16 | 14 |
| Preload Setting (mm of preload R and L fork legs) | 5/5 | 5/5 |
| Oil Volume (Bath Oil) | 100cc | 120cc |
| Oil Weight* (bath/cartridge) | 20/5 | 20/5 |
| Headset Bearing Spacer | reuse stock spacer, seal, bearing | |
| Steerer Spacer 5mm thick above top clamp / beneath top cap |
430-38-018 x2 | |
| Caliper Bracket Caliper bracket is 220mm only. Comes stock with a 220mm rotor. |
430-22-038, 90mm | |
| Wheel Spacers | 430-22-036-360-02 (brake side) 430-22-036-267-02 (non-brake size) |
|
| R38 Shock Settings | Medium | Heavy |
|---|---|---|
| Compression Setting | LSC 13 / HSC 12 | LSC 11 /HSC 12 |
| Rebound Setting | 8 | 7 |
| Spring Rate (N/mm, lb/in) | 110 | 120 |
| Preload Setting (mm) | 3 | 3 |
Settings
Settings are number of clicks from the closed position (full clockwise). Once they are in the closed position, back them out (counter-clockwise) according to the number of clicks indicated in the chart above to get you to factory settings.
CMX Tune Starting Point:
- Assuming neutral riding position, and 15 lbs gear
- Weights of upgrades (battery, controller, etc) to be added to rider weight
- Riders close to a weight cut off need to adjust preload to compensate
- Very aggressive/pro riders to consider +1 weight class and drop preload to get sag. Especially if in the upper range.
- Rider preference and riding conditions may require a different setup
Example:
- 160 lb rider without riding gear, 20 additional lbs with upgraded controller/battery
- Weight calculation 160+20=180
- Aggressive rider = Heavy tune with low preload
- Relaxed rider = Medium tune with high preload
Sirris F43 CMX Fork Installation
Easy Direct Mount Setup
Upgrade your stock Arctic Leopard XE Pro S / Enduro easily with the F43 direct mount front suspension system. No additional modifications or parts are required.
5-Hour Break-In Period Recommendation
The Sirris F43 CMX Fork will break-in during the first 5 hours of use with significant improvements in friction. We recommend that you don’t make significant changes to clicker positions or valving until after the 5-hour break-in period.
Owner’s Guide: Sirris F43 & R38 CMX For Arctic Leopard (PDF) ›