EXT Ferro Front Suspension

At EXT Racing Shox, the research and development of new technologies never
stops. We are focused on progress, bringing the best solution to the market with
the aim to satisfy the needs of the most demanding riders.

Since the growing worldwide success of electric dirt bikes, we saw the
opportunity to take our extraordinary decades-long know-how on dampers, implementing a new custom solution to achieve the highest performance products for our customers. Something that brings your E-MX to the next level!

EXT Racing Shox is extremely proud to introduce the brand new FERRO USD 36,
an upside-down 36mm stanchion fork which is going to complete our E-MX
line-up.

Hard heat-treated chrome moly steel stanchions (Superfinish surface treatment),
7000 series aluminum construction upper legs and a 205mm travel design
with a dedicated triple clamp, make the core of the new 36mm USD fork,
developed for minimum friction and high stiffness.

Together with the popular ARMA MX, already known for its industry leading
reliability and performance, you can now have access to
the best upgrade suspensions package on the market, purposely
built to boost the performance of your electric dirt-bike.

CORE FEATURES

• Robust dual crown inverted MX design (USD)
• 36mm Ø hard chromed steel stanchions (heat treated 42CrMo4) with Superfinish surface treatment
• HS3 3- twin positive air system ¬+ 1 large negative self-balancing air chamber, allows for an optimum level of support through all the travel

• High flow 3-way cartridge damper system with independent high & low speed compression plus rebound damping adjustment.
• Superfinish inner tube coating
• External pressure air release system on both legs
• Twin hexagonal floating axle, boost compatible ∅20mm
• Air spring and cartridge radial guide system with bespoke aeronautical seals (minimize friction on
• side loads)
• Large piston design for best damping control and separate IFP/coil energized compression valve
• No cavitation and low hysteresis
• Self-hydraulic cartridge bleeding
• Dedicated Mobile Sliding DU guiding system with super-long static overlap (for maximum guidance
• and best torsional rigidity). (CGB Continuously Guided Bushing system, increase stiffness)
• 205 mm of travel and 44 mm offset
• 200 mm post mount brake
• Weight 4000gr
• Pressure release one-way valves on both legs
• Compatible with stock fender design 
• Boost Hub Spacing for more flexibility with after market wheel sets.
• NOTE: If you are running a stock wheel or a wheel that is not specifically designed for use with BOOST hubs you will need to install a rotor adaptor that is available HERE

HS3

The FERRO USD 36 fork uses the HS3 technology, the unique hybrid
air spring system, already been famous with the appreciated ERA V2.
Two separate positive air chambers work with one, high volume
self-equalizing negative air chamber; HS3 is focused on mid-stroke
support around the dynamic sag position while offering amazing
sensitivity and bottom-out protection

Fork Structure

Dual Crown Structure:

The robust double crown design in 7075 aluminum ensures maximum stiffness. Crown design is compatible with stock fender designs. 

Sliding Bushings:

 We looked at everything that needed a low friction solution to improve smoothness and sensitivity. This process took us back to our 14 World Rally Championship wins, that make EXT the most succesful suspension manufacturer in WRC. Our new DU bushing material used in the new FERRO USD 36 fork are sized to a defined tolerances for each fork assembly and works in harmony with our dedicated EXT oil. This guarantees zero stiction and super low friction properties even when combined with high side loads.
The dedicated DU guiding system made with a specific superlong bushing overlap ensures the maximum guidance and the best torsional rigidity of the stanchions. (We’ve called it, CGB, Continuously Guided Bushing system which also helps to increase the
dynamic stiffness).

Wheel Axle: Twin hexagonal head floating wheel axle guarantees perfect wheel alignment, while assuring maximum torsional rigidity.

High Flow Damper Cartridge 

The new FERRO USD 36 inherits the best technologies that made famous our well-known ERA V2 and it adopts an innovative radial floating shaft guide in the damper cartridge with a Superfinish surface treatment with new aeronautical seals, which takes the friction to the lowest possible level. EXT high-volume cartridge uses a high flow piston to generate control for your bike, an important performance upgrade for your riding. The large piston design allows the best damping control. The cartridge is also equipped with a bump valve design (HDRV – High Dynamic Response Valve) with 2 different shim stacks for mid and high speed and an Internal Floating Piston (IFP) guided and combined with a bespoke thrust bearing to enhance fast response and guidance. Our goal has always been to find a balance between all the internal cartridge pressures and through a long development process we made possible the optimization of the internal forces reaching low values of hysteresis and no cavitation.