Surron Ultra Bee

F43 Trail Tune Fork | LSC | 246mm Travel

Dominate the trails with the fork built for speed, control, and confidence. The F43 Trail Tune isn’t just suspension—it’s your secret weapon. Designed for aggressive riders who want sporty support across gnarly terrain, this fork is versatile, predictable, and ready to smash lap times or shred all-day singletrack.

With 246mm of plush travel, closed-cartridge damping, and a hydraulic bump stop, the F43 soaks up big hits while keeping things buttery smooth when you’re pushing limits. Whether you’re an e-moto weekend warrior or a pro chasing podiums, this fork delivers a ride that’s fast, supportive, and confidence-inspiring.

Complete your ride with the Sirris R46 Trail Tune Shock!

Features 🏁

• Trail Tune Setup – Sporty & aggressive valving for all-terrain performance

• Closed Cartridge System – Consistent damping that won’t fade mid-ride

• Hydraulic Bump Stop – Smooth landings on the biggest hits

• High-Tensile Springs – Lightweight yet durable for long-lasting performance

• Fully Adjustable – Compression, rebound & preload for custom tuning

• Built for E-Moto – Handles heavy builds, upgraded controllers, and aggressive riding styles

Rider Weight Options ⚡️

Sirris offers six rider weight ranges (without gear—15 lbs is added for gear):

• 130–160 lbs → Light (4.0/4.0 springs)

• 160–210 lbs → Medium (4.8/4.4 springs)

• 210–230 lbs → Heavy (5.0/4.8 springs)

• 230–250 lbs → X Heavy (5.0/5.0 springs)

• 250–280 lbs → XX Heavy (5.4/5.0 springs)

• 280–350 lbs → XXX Heavy (5.8/5.4 springs)

👉 Pro tip: Aggressive riders may want to size up one weight class and adjust preload for sag.

TUNING DETAILS & RIDER WEIGHT RANGE

TRAIL TUNE Starting point notes:

Assuming neutral riding position, with 15 lbs gear on.
Weights of upgrades (battery, controller, etc) to be added to rider weight
Stock bike with 18/21 wheels
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:
190 lb rider without gear, 20 additional lbs with upgraded controller/battery
Weight calculation 190+20 = 210
Aggressive rider = Heavy tune with low preload
Relaxed rider = Medium tune with high preload

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.

*OIL NOTE: Sirris uses Shell Tellus S2 VX15 (5wt) in the fork cartridge and Shell Tellus S2 VX68 (20wt) as the bath oil. These are cross compatible with other high quality 5wt and 20wt suspension fluids.  Sirris uses a semi-synthetic 2.5wt oil in the shock that is also compatible with other high quality 2.5wt aftermarket suspension fluids. You can use 5wt/20wt oils of your preference, Lubefinder.com can be used to source the fork oils. KYB K2C can be used in the shock and has wide availability.