NEW CMX TUNE
F43 FORK FOR SURRON LIGHT BEE X
This isn’t just an upgrade—it’s suspension done right. For everyone wondering why their Surron Light Bee X can’t feel like their gas race bike, this fork is the answer.
The all-new CMX Tune (Compact Motocross) with 220mm of travel — paired with our race-proven F43 platform — brings elite-level suspension tech to the electric world, engineered without compromise for the Surron LBX.
This is simply not a scaled-down fork. It’s a purpose-built motocross suspension weapon, reimagined for the most aggressive e-riders on the planet.
Unmatched strength. Precision tuning. Unrivaled performance.
Every detail built for total dominance:
- NEW Tool-free compression adjust
- NEW Optional drop-clamp for 21” wheels
- NEW Lightweight billet clamps with direct mount stem compatibility
- NEW Ultra stiff axle and drop out assembly promotes front end feel and steering precision
- NEW Replaceable caliper mount brackets allow for caliper and wheel upgrades
- 178mm fork spacing allows unlimited tire selection from aggressive knobby to supermoto treads
- Symmetrical closed cartridge dampers are specifically tuned for each model, and fully tunable for spring rate and damping
- Motorcycle style top cap increases ability to tension steering bearings and retain torque
You wanted the best? This is it.
F43 CMX Tune | Tool Free LSC | 220 mm Travel | Surron Light Bee X
Sirris offers two weight ranges when selecting your CMX Tune F43 fork for Surron Light Bee X (LBX). (Listed weight ranges are rider weight without riding gear on. 15 pounds of riding gear is calculated into the weight ranges)
140 lbs - 180 lbs (Medium = 3.6/3.2 springs)
180 lbs - 220 lbs (Heavy = 3.6/3.6 springs)
Fork spring rates listed above are left side/right side.
FORK SPECS:
Architecture
Upside down fork
Travel
220 mm
Free length
775 mm
(drop clamp option adds another 25mm of extended length)
Fork Spacing
178 mm - 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
Ø43, 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-degree wraparound
CMX TUNE
DOMINATE THE TRACK
The Compact Motocross Tune F43 is an unapologetic race fork, built for elite-level racers chasing podiums—but it's just as powerful in the hands of everyday rippers looking to level up. Razor-sharp when you push it, forgiving when you need it. This is the ultimate performance upgrade.
FULL SPEED. FULL CONTROL. NO COMPROMISE.
The CMX Tune is purpose-built for the high-speed demands of the lightweight e-moto class—engineered to dominate any terrain, any time, anywhere. Whatever you throw at it, it’s ready.
CMX TUNE
DOMINATE THE TRACK
The Compact Motocross Tune F43 is an unapologetic race fork, built for elite-level racers chasing podiums—but it's just as powerful in the hands of everyday rippers looking to level up. Razor-sharp when you push it, forgiving when you need it. This is the ultimate performance upgrade.
FULL SPEED. FULL CONTROL. NO COMPROMISE.
The CMX Tune is purpose-built for the high-speed demands of the lightweight e-moto class—engineered to dominate any terrain, any time, anywhere. Whatever you throw at it, it’s ready.
TUNING DETAILS & RIDER WEIGHT RANGE
Listed weight ranges are body weight without riding gear (15 pounds of riding gear is calculated into the weight ranges).
Weights of upgrades (battery, controller, etc) need to be added to rider weight.
SETTINGS NOTE: 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 notes:
- 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
SHOCK PAIRING NOTE:
We currently do not have a rear shock to fit the Surron Light Bee X.
For optimal bike performance, we recommend stock shock settings:
MEDIUM TUNE FORK - Use with: 79 N/mm (450lb) stock spring, compression 5, rebound 7, 3mm preload.
HEAVY TUNE FORK - Use with: 88 N/mm (500lb) spring, compression 3, rebound 5, 3mm preload.
TRUE SYMMETRICAL CLOSED CARTRIDGE
BALANCED PERFORMANCE
No matter how hard you ride or how many laps you take, our closed cartridge forks will never fade and will always feel predictable.
HYDRAULIC BUMP STOP
Go big with confidence, control, and comfort. Our hydraulic bump stop design and construction gives you a soft landing at max stroke even on the most aggressive impacts.
HIGH TENSILE LIGHTWEIGHT SPRINGS
Weighs only 8.8 lbs (4 kg) per leg (standard configuration spring).
NO COMPROMISES
DUAL OIL CIRCUITS FOR OPTIMUM PERFORMANCE
Separating lubrication and damping oils allows us to further optimize high and low speed damping performance.
HIGH QUALITY MATERIALS + SURFACE TREATMENTS
All cartridge bodies and outer tubes are hard anodized 7XXX series aluminum providing high durability and scratch resistance to keep your ride in top condition.
EVERY RIDER & RIDING STYLE
Fully tunable valving on compression and rebound, with spring rates matched to rider weight and riding type. Adapt your suspension setup for different types of rides, enhancing overall riding experience.
Compression, rebound, and preload adjust plus custom spring rates for all riding styles and rider sizes.
TECH HELP
Suspension setup, owner's guide, tech help, warranty and more. Learn how to properly set up, use, and maintain your new Sirris suspension products.
NEWS & INSPO
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SX Suspension Has Landed
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Victory at Biltwell 100
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Mint400 E-Moto Win
Altis Sigma and Arctic Leopard EX 800 equipped with custom Sirris F43 suspension forks make history.
Ultra Bee Arenacross Racing
Josh Hill and crew racing hard on Sirris equipped Surron Ultra Bees at the Red Line Oil Arenacross race in Shelbyville TN.
