Motion reinvents the XC fork: claims the world’s lightest and features a rear shock

The Motion X-Elium is one of those forks that is hard to identify as such at first glance. It has no stanchions, no lowers, and no bridge; instead, it uses a carbon monocoque chassis, an articulated system, and a Fox Float SL shock. A completely different architecture with which the brand claims to have created the lightest 120 mm XC fork in the world, with only 1.2 kg of declared weight.

Motion X-Elium: a 120 mm XC fork that weighs only 1.2 kg and features a rear shock

Motion Engineering has been developing suspension systems and vehicle dynamics for over a decade, and with the X-Elium, it has practically started from a blank slate. The goal was not to improve an existing fork but to eliminate some of the limitations that, according to the company, are inherent to this design.

The fact that immediately places the X-Elium on the map is its weight. Motion claims 1.2 kg including the shock for a fork with 120 mm of travel, a figure that positions it below the main current XC references.

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But to get there, it has not simply resorted to lighter materials. Motion has completely changed the architecture.

The head tube and the main body form a carbon fiber monocoque structure located on one side of the wheel. This connects to the axle via an articulated system with machined 7075-T6 aluminum components, eliminating the traditional stanchions sliding inside lowers.

And where we would expect to find a hydraulic cartridge and a pneumatic spring, probably the most striking element of the entire assembly appears: a Fox Float SL Factory Kashima rear shock of 190 x 45 mm.

The shock features a specific configuration developed by Motion and offers rebound and compression adjustment via a three-position remote control. Additionally, by using a standard format, it can also be replaced by a RockShox SID Luxe.

Less unsprung mass and no friction between stanchions and bushings

One of the main advantages that Motion attributes to this architecture is the reduction of unsprung mass.

The company estimates that in a telescopic fork, the lowers and other moving components can represent up to 65% of the total weight. In the X-Elium, Motion estimates the unsprung mass at approximately 100 grams, compared to nearly 1 kg that it takes as a reference in a telescopic fork.

Reducing that mass should allow the wheel to respond more quickly to small irregularities and sequences of impacts, improving sensitivity and contact with the ground.

The friction generated by stanchions, seals, and bushings subjected simultaneously to forces from steering, braking, and impacts also disappears. In the X-Elium, the shock is isolated from those loads and works aligned exclusively within the suspension system.

Anti-dive to prevent the fork from sinking when braking

The articulated kinematics also allows for the introduction of a feature that is practically impossible to achieve this way in a conventional fork: an anti-dive system.

When we brake hard, the mass transfer to the front wheel causes a telescopic fork to compress. This modifies the geometry of the bike and reduces the travel available to absorb obstacles.

Motion claims that the X-Elium achieves 100% anti-dive in the SAG position. The forces generated during braking act on the kinematics itself to counteract the sinking of the suspension.

The goal is to maintain a more stable position during hard braking and preserve the available travel without having to excessively increase hydraulic compression.

The wheel is also not forced to follow the straight trajectory of telescopic stanchions. From full extension, the axle initially moves forward about 7 mm before moving backward, achieving 40 mm of rearward movement at the end of the travel.

Motion claims a stiffness comparable to a SID 35

A structure this light and with a single arm inevitably raises doubts about its stiffness. Motion claims that its own tests place the X-Elium at a level comparable in torsional and longitudinal stiffness to a RockShox SID of 35 mm.

To achieve this, the main chassis is made of carbon, and the piece that connects the articulated system to the axle uses CNC-machined 7075-T6 aluminum.

The architecture requires a specific Motion front hub with 28 straight-pull spokes, although it allows for a symmetrical wheel build. The brand is also preparing different versions of the hub, including one compatible with BERD spokes.

The same fork for 29" and 32" wheels

The absence of lowers and a bridge also facilitates something particularly interesting, looking towards where XC is evolving, which is to use larger wheels.

The X-Elium offers 120 mm of travel with a 29" wheel and can be configured for a 32" wheel, in which case the travel is 90 mm. Motion explains that the change is made via a hydraulic token installed in the shock.

The brand also plans to develop different kinematic kits that will allow modifying in the future the leverage ratio, progression, travel, and even the level of anti-dive.

Additionally, Motion announces a reduction of 25% of the frontal area compared to a conventional XC fork and uses aerodynamic profiles shaped like a teardrop. The absence of a bridge also leaves more space to evacuate mud, although the maximum tire size specified is 2.4".

Features of the Motion X-Elium

• Weight: 1.2 kg
• Travel: 120 mm on 29" / 90 mm on 32"
• Axle-to-crown: 530 mm
• Offset: 44 mm
• Chassis: carbon monocoque
• Articulated components: CNC machined 7075-T6 aluminum
• Shock: Fox Float SL Factory 190 x 45 mm
• Alternative compatibility: RockShox SID Luxe
• Hub: Motion, 28 straight-pull spokes
• Maximum tire: 2.4"
• Brake: Post Mount, minimum 180 mm disc
• Steering: tapered 1.5"

Price and availability

Motion needs to reach 100 reservations before starting the first production of the X-Elium. For those first units, it has set a launch price of 875 euros excluding taxes, including the Fox Float SL and the specific hub. After that, the announced price will rise to 1,250 euros excluding taxes.

More information on the official brand website.