Sirris F43 Fork CMX Tune: Ventus One+
- Lead Time: Ships in 5 Days
Take your Ventus One+ to the next level with the Sirris F43 CMX Fork. This 220mm travel fork is engineered without compromise specifically for the Ventus One+ for high-performance, aggressive riding. The CMX Tune (Compact Motocross) paired with the race-proven F43 platform brings elite-level suspension tech to the electric dirt bike world.
140 lbs - 180 lbs (Medium = 3.6/3.6 springs)
180 lbs - 220 lbs (Heavy = 4.0/3.6 springs)
Fork spring rates listed above are left/right side.
See Stock Shock Tuning Chart below
Sirris F43 CMX Fork Features
- 220mm Travel — (17mm more than stock) adds cushioning for aggressive riding
- Tool-Free Compression Adjusters — for quicker changes during mid ride without any tools needed
- 178mm Fork Spacing — allows unlimited tire selection from aggressive knobby to supermoto treads
- Drop Clamp Option for 21" Wheels — allows for fitment of 21” wheel by raising the front end an additional 25mm while retaining 220mm travel (raising the front end maintains balance of the bike if paired with a longer shock that raises the rear)
- Scalloped Clamps — for aggressive, trick styling
- Direct Mount Stem (DM Ready) — lightweight billet clamps with DM stem designed for hassle-free setup (no extra parts needed)
- Axle & Brake Mounts — ultra-stiff and configurable
- Axle and drop out assembly promotes front-end feel and steering precision
- Universal lugs, custom axle spacers and new brake mounts allow for easier stocking, and allows rider greater wheel and brake options
- Replaceable caliper mount brackets allow for caliper upgrades
- Symmetrical Closed Cartridge Dampers — specifically tuned for each model, and fully tunable for spring rate and damping for balanced performance
- Motorcycle-Style Top Cap — increases ability to tension steering bearings and retain torque
- Available in MEDIUM and HEAVY tune
OEM Ventus One Compatibility
The triple clamps and guards perfectly align with the Ventus One+ fairing and cable routing. Additionally, the CMX F43 Fork upgrade is compatible with the Ventus One+ stock display, fender, and brake as well.
F43 CMX Fork Specs
| Architecture | Upside down fork |
| Travel | 220mm |
| Free length | 775mm (drop clamp option adds another 25mm of extended length) |
| Fork Spacing | 178mm - allows for unlimited tire choice (dirt or street) |
| Fork weight | 4 kg per leg (driven by sturdy construction required for the forces and speeds encountered when pushing these bikes to their limits without compromising performance) |
| Stanchions | 43mm - high tensile steel with hard chrome |
| Outer tubes | Seamless 7050 aluminum, type 3 hard anodized coating |
| Drop outs | 6061 aluminum, type 2 anodized coating Replaceable caliper mount brackets allow for caliper and wheel upgrades |
| Axle | Ultra-high tensile hard chromed axle increases steering precision and confidence |
| Triple clamps | Billet 6061 aluminum, type 2 anodized coating, 3 color options (blue, red, black) Optional drop clamp allows for 21” front wheel conversion (black only) |
| Steer tube | Seamless 7050 aluminum, type 2 anodized coating |
| Damping | Symmetrical, adjustable closed cartridge with spring backed modified IFP |
| Damper bodies | Seamless 7050 aluminum, type 3 hard anodized coating |
| Rebound | Dual side high tensile steel spring, adjustable |
| Adjusters | External tool-free compression, rebound adjustment (rebound adjusted using tool) |
| Seals | NOK MX seals |
| Bushings | Daido MX bushings |
| Guards | High impact PP, 210° wraparound |
CMX Tuning Details & Rider Weight Ranges
Sirris offers 2 weight ranges to choose from when selecting your CMX Tune F43 Fork for Ventus One+. Listed weight ranges are body weight with 15 lbs of riding gear. Weights of upgrades (e.g. battery, controller, motor) need to be added to rider weight.
| FORK Recommendations | Medium | Heavy |
|---|---|---|
| Rider Weight (lbs) (No Gear) | 140-180 | 180-220 |
| Spring Rate (N/mm) | 3.6/3.6 | 4.0/3.6 |
| Fork Height in Upper Clamp (mm) | 8 | 8 |
| Compression Setting | 18 | 16 |
| Rebound Setting | 18 | 16 |
| Preload Setting (mm of preload R and L fork legs) | 5/5 | 5/5 |
| Oil Volume (Bath Oil) | 100cc | 110cc |
| Oil Weight* (bath/cartridge) | 20/5 | 20/5 |
| Headset Spacer 1mm thick washer beneath seal, PN 430-38-017 | 430-38-017 x1 | |
| Steerer Spacer 5mm thick above top clamp / beneath top cap | 430-38-018 x1 | |
| Caliper Bracket | 430-22-032, 74mm | |
| Brake Line Shim for 5mm thick line | 430-52-001-XXX-XX | |
| Wheel Spacers | 430-22-036-360 x2 430-22-036-267 x2 |
|
| SHOCK (Stock) Recommendations | Medium | Heavy |
|---|---|---|
| Compression Setting | 6 | 4 |
| Rebound Setting | 10 | 8 |
| Spring Rate (N/mm, lb/in) | 88, 500 | 96, 550 |
| Preload Setting (mm) | 3.5 | 3.5 |
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 Fork Installation
Easy Direct Mount Setup Upgrade your stock Ventus One+ easily with the direct mount front suspension system. No additional modifications or parts are required.
5-Hour Break-In Period Recommendation The Sirris F43 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.