As I can attest from experience, these GP100-worthy bikes get even more fun to ride with a built-in boost. Close-up of a dirt bike front wheel and fork with "SIRRIS" branding on the suspension.If you buy from a link, we may earn a commission. Learn moreLast fall I was stoked to join Zero Motorcycles at TouraTexas, the off-road expo at which the brand rolled out its ambitious first electric dirt bikes, the XE and XB.As an e-moto skeptic, I was delighted to discover how much fun they are, and how welcoming they are to off-road noobs.Above is yours truly, the author, unwittingly beta testing the then-experimental Sirrus fork at TouraTexas last fall. - Credit: Zero MotorcyclesThat aspect was enough to help them crack last year’s GP100, and they only get more compelling with the news that they’ve teamed up with Sirris on a custom-built suspension you can buy.AdvertisementAdvertisementHaving actually ridden that exact suspension out in Texas, I can tell you that it only makes these bikes more of a delight.Sirrus improvementIn retrospect, I can see Zero used that event to beta test the suspension set-ups, which the brands have collaboratively crafted into pitch-perfect plug-and-play upgrades to the stock shocks.Let’s start with the smaller and more approachable of the two bikes, the XB, for which the brands designed a brand-new front setup, the F43 CMX Fork. Zero and Sirris teamed up to dial in the F43 perfectly for both the XB (shown) and the XE. - Credit: Zero MotorcyclesHighlights include a symmetrical closed cartridge design and dual independent sealed dampers, optimized for this exact bike for improved performance on mixed surfaces.The $2,250 bolt-on comes with all you need to make the swap, including a spacer, caliper bracket and brake line routing components.The bikes, in general, are quite approachable to a wide range of riders. Here you can see how comfortably one can sit on the XB, which tips the scales at just 139 pounds. Doesn’t hurt that the Sirris fork looks so sick, too. - Credit: Zero MotorcyclesThe larger and more powerful XE, meanwhile, is eligible for a total suspension overhaul.AdvertisementAdvertisementIt involves the same F43 CMX Fork, retuned to accommodate the bigger, heavier bike, plus an R46 rear shock.The fork and shock were tuned in tandem for balanced geometry and off-road predictability, but there’s also a race tune if that’s how you roll.The XE gets a full suspension upgrade via the R46 in the back and the F43 CMX in the front. - Credit: Zero MotorcyclesAdding to the appeal, both the forks and rear shock are fully adjustable for compression, rebound, preload, and spring rates, enabling you to modify them to your liking. To be clear, I knew absolutely none of this last fall when I was ripping around on these bikes, grinning and whooping in spite of myself. That said, I could definitely sense the difference between the stock shocks and the Sirris upgrades, which felt both livelier and more forgiving. Here, you can see a rider, definitely not the author, giving the upgraded suspension a high-flying workout. - Credit: Zero MotorcyclesInterestingly, thanks to the XE’s recent price drop (it’s now $5,995, while the XB holds steady at $4,395), both upgrades are basically half the cost of the bikes themselves, though that says at least as much about the tempting affordability of the X Line.AdvertisementAdvertisementPlus, if you ride the bikes a ton and they make things at least 50 percent more fun, you might just leave your memory of the price tag in the dust.Availability and pricingThe Sirris F43 XB CMX Tune Fork and F43 XE Trail Tune Fork are available now for $2,250. (The R46 XE Trail Tune Shock costs $895.)Two white and black dirt bikes with red accents and large knobby tires on a sandy surface.Sirris F43 XB CMX Tune Fork / Sirris F43 XE Trail Tune Fork $2,250 at Zero Motorcycles About the Author:Now managing editor, Steve has served in a variety of roles with GP since 2019. Having previously written and edited for such publications as Men’s Health, Men’s Journal, Esquire and ESPN, he enjoys covering a range of topics — but mostly those pertaining to cycling, snow sports, pocket knives and motos — and dreams of a utopian world in which everyone’s bike seat is at the proper height.AdvertisementAdvertisementWant to stay up to date on the latest product news and releases? Add Gear Patrol as a preferred source to ensure our independent journalism makes it to the top of your Google search results.add as a preferred source on google