Zero Motorcycles and Sirris team up on performance suspension upgrades for the Zero X Line
Zero Motorcycles has announced a new partnership with Sirris to bring purpose-built suspension upgrades to its X Line, and for riders who’ve been pushing their XB or XE to the limit, this is worth paying attention to.
The collaboration produces two offerings: the Sirris F43 CMX fork for the XB, and a complete F43/R46 front-and-rear suspension system for the XE. Both are engineered as direct bolt-on replacements for the stock setup, meaning no fabrication headaches for the rider.
Sirris isn’t a new name in suspension circles. Founded by a team with deep roots in suspension design, manufacturing, and race-level tuning, the company builds model-specific solutions tailored to the unique demands of electric off-road bikes: the different weight distribution, the instant torque delivery, the riding characteristics that set e-motos apart from their combustion counterparts. Their setups are shaped by real-world rider feedback and athlete testing at the sharp end of the sport.
Zero handled ride tuning, vehicle integration, and validation across varied terrain, while Sirris brought the hardware engineering and manufacturing. The work apparently started early. “Starting from the initial launch of our new X Line motorcycles, we’ve been working with Sirris to customize performance suspension profiles for the most demanding riding conditions,” said Garrett Johnson, Zero’s VP of Sales & CX for North America.
What’s in the box
For XB riders, the F43 CMX fork runs a symmetrical closed cartridge design with dual independent sealed dampers. It comes factory-set at a 3.6/3.2 N/mm spring rate and is fully adjustable, with available spring rates spanning 3.2 to 5.8 N/mm. You can also run mixed rates between fork legs if you want to get precise about your feel. Installation uses the stock Zero XB stem with an included spacer, and the kit ships with a caliper bracket, wheel spacers, and a brake line routing solution designed around stock XB geometry.
Learn more about the Sirris F43 CMX fork for Zero XB.
The XE package pairs the F43 fork, factory-set at 4.4/4.0 N/mm, with the R46 rear shock at 105 N/mm, tuned together for balanced geometry and consistent trail performance. There’s also a race tune available: fork spring rates up to 4.8/4.4 N/mm, increased oil volume, and a 115 N/mm shock spring rate for riders heading into more serious terrain. The rear shock accommodates spring rates from 75 to 115 N/mm, giving room to adjust for rider weight, riding style, or battery upgrades.
Take a deeper dive into the full product specs:
> Sirris F43 fork for Zero XE
> Sirris R46 shock for Zero XE
Co-founder Graham Sills puts it plainly: “E-Moto is, in our opinion, the most exciting new space in the powersports world.” That sentiment is hard to argue with, and the fact that riders are demanding more capability from their machines, and that companies are responding with serious hardware, says a lot about where the segment is heading.
About Sirris
Sirris Inc. has built a strong reputation in the e-moto space, developing advanced suspension systems specifically for high-performance electric off-road motorcycles. The company was founded by a team with deep roots in suspension engineering, product development, manufacturing, and race-level tuning. That hands-on experience shows in how they approach the work. Rather than adapting existing solutions, Sirris builds from the ground up for electric, collaborating directly with OEMs and motorcycle brands to create suspension setups tuned for the unique demands of e-moto riding: the weight, the torque, the terrain. The goal is simple: better handling, more stability, and greater rider confidence, whatever the conditions.
Source: press release Zero Motorcycles
