Zero XB and XE: Sirris Delivers the Suspension the X Line Bikes Were Missing

• Sirris F43 CMX fork for the Zero XB from $2,250 (approximately €2,020)
• F43 fork and R46 shock absorber as a complete system for the Zero XE
• Full adjustability on all components, including optional race setup

Zero Motorcycles has teamed up with Sirris Inc., a suspension manufacturer specializing in electric off-roaders, to introduce two new suspension options for the X Line models XB and XE. The collaboration combines Zero’s platform with the expertise of Sirris, a company that draws on decades of experience in suspension design, manufacturing, and race tuning. Sirris develops model-specific solutions tailored to the unique weight distribution, torque characteristics, and handling properties of electric off-road motorcycles. The tuning is based on feedback from real-world riding conditions and tests with top-level off-road pilots.

What Does the Sirris F43 CMX Fork Offer for the Zero XB?

The Sirris F43 CMX fork for the XB is an upside-down fork with a symmetrical closed-cartridge design and two independent, sealed damping units. It was specifically tuned to match the geometry, weight distribution, and mixed-use application range of the XB. The system offers 220 mm of travel, providing 17 mm more than the stock suspension.

The factory setup comes with spring rates of 3.6/3.2 N/mm (left/right). The entire system is fully adjustable, with available spring rates ranging from 3.2 to 5.8 N/mm. A notable feature: different spring rates can be combined in the two fork legs to achieve a custom-tuned setup.

The stanchions measure 43 mm in diameter and are made of high-strength steel with hard chrome coating. The outer tubes are crafted from seamless 7050 aluminum with Type 3 hard anodizing. Each fork leg weighs 4 kg. New to the CMX version is a tool-free compression adjuster that allows adjustments on the fly without a screwdriver. With a fork spacing of 178 mm, tire selection is flexible, from aggressive knobby tires to supermoto rubber. An optional drop-clamp variant is available, enabling the installation of 21-inch wheels while raising the front wheel by an additional 25 mm without sacrificing travel.

Installation uses the stock steering head of the Zero XB in combination with an included spacer. The package also includes the brake caliper mount, wheel spacers, and a brake line routing designed to match the stock wheels and suspension geometry of the XB.

What Suspension Components Are Available for the Zero XE?

For the XE, Sirris offers a complete system consisting of the F43 fork and R46 shock absorber. The fork comes factory-set with spring rates of 4.4/4.0 N/mm, while the R46 shock features a spring rate of 105 N/mm. Both components were matched to ensure balanced suspension geometry and consistent off-road performance.

For riders with higher demands, a race setup is also available. This includes higher fork spring rates of up to 4.8/4.4 N/mm, increased oil volume, and a stiffer 115 N/mm spring for the shock. This setup is designed for particularly demanding conditions, such as competitive racing.

As with the XB fork, the XE system also offers full adjustability for compression, rebound, preload, and spring rate across a wide range. The rear shock is compatible with spring rates from 75 to 115 N/mm, accommodating different rider weights, riding styles, and vehicle configurations. According to Sirris, this also accounts for battery upgrades that change the overall vehicle weight.

How Was the Work Divided Between Zero and Sirris?

Zero Motorcycles handled the suspension tuning, vehicle integration, and validation across a wide range of conditions. Sirris was responsible for the development and manufacturing of the hardware. This division is also reflected in support: Sirris stands behind the design and manufacturing of the suspension components, while Zero manages vehicle-specific tuning, setup recommendations, and installation instructions.

Graham Sills, one of the founders of Sirris, puts the collaboration into perspective: “E-Moto is, in our opinion, the most exciting new space in the powersports world. Our collaboration with Zero on their XB and XE perfectly demonstrates the movement of riders demanding more and more capability from their e-motos.”

Sills adds on the tuning philosophy: “Sirris suspension is perfectly tuneable. The performance for the demands of rider weight and terrain can often be optimised simply by adjusting the spring rate or the damping.”

Garrett Johnson, Vice President Sales & Customer Experience North America at Zero Motorcycles, says that work on the performance suspension components has been underway since the X Line models first hit the market: “Now, we’re excited to offer these optimised solutions as turnkey upgrades to all our customers who want to push their XE or XB harder, whether they’re looking for more control on the trail or lining up to race.”

How Much Do the Sirris Suspension Components Cost?

The Sirris F43 CMX fork for the Zero XB is listed at $2,250 (approximately €2,020) in the Sirris Store and through authorized dealers. The F43 fork for the Zero XE is also priced at $2,250 (approximately €2,020). The R46 shock for the XE costs $899 (approximately €807). Combining the complete fork and shock system for the XE brings the total to around $3,149 (approximately €2,827).

For context: the Zero XB itself is available in Germany from €4,400, and the Zero XE from €6,400. The suspension upgrades are thus priced at roughly half the XB’s vehicle price and about a third of the XE’s price. While this is not unusual for ambitious suspension upgrades in the off-road segment, it clearly shows that the offering is aimed at riders who seriously use their machines in terrain or competition.

How Do the Upgrades Fit Into the E-Moto Market?

Early ride reports on the Zero XE rated the stock suspension as solid for general trail use, while noting that an upgrade would be advisable for higher speeds, bigger jumps, or racing. The Sirris components had already been mentioned as a potential option. With their official launch as a Zero-validated plug-and-play system, X Line owners now have a factory-approved solution without having to resort to third-party modifications.

Sirris is no newcomer to the e-moto segment. The company offers comparable suspension solutions for other electric off-roaders, including models from Sur-Ron, Talaria, and E-Ride. The collaboration with Zero is thus part of a broader strategy targeting the growing demand for high-performance suspension in the lightweight electric class.

According to Zero, all new suspension components are available immediately through the authorized dealer network.

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