Arctic Cat Catalyst M 858 Alpha One Sno Pro 2025

m 858 alpha one

There are many great combinations in Arctic Cat’s Mountain line up for model year 2025. I was having a great time trying all the different lengths, track and suspension packages at Snow Shoot this year. After burning lots of fuel in the mountains of Montana, trying Arctic Cat’s new mountain sled packages, I settled on my favourite combination: the Catalyst M 858 Alpha One, 3-inch Power Claw Track with the Sno Pro Suspension Package in the 154-inch length and here’s why.

m 858 alpha one sno pro

My Favourite Sled of Arctic Cats Model Year 2025

  • Catalyst M 858 Alpha One
  • Sno Pro Suspension Package with AC5S Shocks
  • 3″ Power Claw Track
  • 154″ Track Length

858 C-TEC2 Engine

moteur 858

To begin with, the all-new 858 two-stroke engine was the increase in horsepower we were looking for in the Catalyst chassis last season. The seamless engine integration allows it to fit low in the platform and keep the mass centralized while leaving the sled feeling light, nimble and playful. Not only did Arctic Cat keep the lightweight feel with the new 858 motor but designed it specifically for the Catalyst platform. They also gave us an 8% increase in displacement and an 11% increase in output over the C-TEC2 800, all while weighing 4% less. Having an engine that’s lighter and stronger is always welcome and encouraged, but especially in a mountain sled.

How’s the Performance of the 858 Engine?

The new 858 engine definitely outperforms the 800 C-TEC2 that they had in the Ascender platform. It’s lighter, has more power and was specifically designed to be mounted low and keep the weight centralized in the Catalyst chassis. The new 858 engine really helps enhance the fun playfulness of the catalyst M chassis and has propelled this sled to be able to battle in steeper and more technical terrain.

858 Engine Enhancements

After testing the new 858 engine, I would like to ask the engineers to tweak a few things. The first would be giving the motor a bit more low-end snap. The motor pulls hard in the mid-range and top end, but is slightly slower on the bottom end. A chassis like the lightweight and playful Catalyst would benefit a lot from a quicker revving motor. I’m not trying to say the 858 shows lag, because it doesn’t, it just could be slightly quicker on the low end. This might also be solved by making some adjustments in the clutching.

The other modification to the motor that would enhance it would be to reduce some of the vibrations. Some of this could be that we’re riding prototype sleds that are hand-built and not the final design. But either way, fewer vibrations coming through the bars and running boards would enhance the rider’s experience.

Sno Pro Suspension Package

This year in Arctic Cat’s Mountain line there are three different shock packages available, Internal Floating Piston Shocks (IFP), AC5S (Sno Pro Models), and ATAC Adjustable On-the-Fly suspension. Our team had the opportunity to try all the suspension packages on many sleds and over the course of multiple days. All three suspension packages performed well but I personally liked the AC5S Sno Pro suspension set up the best. One reason was how easy it was to quickly adjust the five clicker settings on both the front and rear shocks. They also had a wide range within those settings from soft to very firm, and even lockout on the rear shocks. The AC5S suspension also felt like a higher performing suspension than the IFP and the ATAC, in my opinion. Another reason was that the ATAC in its softest setting was still slightly too firm for my riding style.

Internal Floating Piston (IFP) Shocks

The IFP suspension is Arctic Cat’s base level suspension package. For a base level suspension, it performed well, and I had no complaints. It’s lightweight, smooth, and controllable, which is great for playing in the mountains. The IFP suspension is a re-buildable shock, meaning a rider can fine-tune the valving if they want. Otherwise, the only adjustment available for this suspension is the level of compression in the preload springs.

Internal Floating Piston (IFP) Shocks
Internal Floating Piston (IFP) Shocks

AC5S Shocks (Sno Pro Models)

The AC5S shocks offer five different clicker valving positions as well as an adjustable spring preload. Arctic Cat also says that they are uniquely calibrated for backcountry riding. After riding and trying all five settings in the backcountry over multiple days, I would agree with them. The AC5S suspension was, by far, my favourite of Arctic Cat’s Mountain line, because of the range and ease of adjustability.

AC5S Shocks on the M 858 Alpha One Sno Pro
AC5S Shocks

ATAC Adjustable On-the-Fly Suspension

ATAC Adjustable On-the-Fly Suspension is an electronically controlled suspension that can be adjusted from the gauge cluster on the handlebars. With push-button command of three firmness settings, you can adjust the shock settings as you’re riding. With the ATAC suspension package, the rider has a lockout mode and two individual rider profiles that let you dial in the suspension to your preferences quickly. I’m sure once you get used to adjusting the settings it gets easier. But, initially, our team was struggling a little bit to unlock the suspension settings and change the firmness. I also feel like the softest setting on the ATAC suspension was too stiff and should be softened quite a bit.

ATAC Adjustable Suspension
ATAC Adjustable Suspension

Alpha One Single-Beam Rear Suspension

With the Alpha One Single-Beam rear suspension, the snowmobile is very maneuverable. Even with a longer track length, your sled can handle tighter turns in technical situations with this design. The combination of the Catalyst centralized weight design and the Alpha rear suspension really complement each other. This combination gives this sled a lightweight, playful personality that our team really appreciated and enjoyed.

Rear suspension on the m 858 alpha one sno pro
Alpha One Single-Beam Rear Suspension

36″ Arctic Wishbone Suspension (AWS)

AWS 36 is the Arctic Wishbone Suspension, optimized by Arctic Cat engineers for deep snow riding. By centralizing the weight distribution, the suspension now sits more directly under the rider, offering more sled control.

The vertical steering system has been designed for smoother and easier steering requiring less rider input. With less rider input into the steering system, it allows the rider to react quicker for technical riding and experience less shoulder fatigue throughout the day.

The spindles on the M 858 Alpha One have also been redesigned by shortening the top end but lengthening the spindle overall. The design was adjusted so the spindles would be more durable, while remaining lightweight.

Power Claw 3″ Track

The three-inch Power Claw track was, in my opinion, the clear winner in the deep snow and steep terrain. The main reason I picked the 3.0″ over the 2.6″ was the deeper lug and its 10 lb lighter weight. Being 10 lb lighter is a big deal, especially when it comes to the performance of the sled with the extra rotating mass. The 2.6″ would probably work slightly better in set-up or late-season snow and is probably a better option for a combination of on- and off-trail riding.

Catalyst M 858 Alpha One Future Enhancements

34″ Ski Stance

An idea for the engineers is to try a 34″ front end for an extra level of manoeuvrability and excitement. Changing the ski width by two inches has a big effect on how easy the sled comes over and the amount of rider input that’s needed. The Catalyst M 858 Alpha One is a very fun and playful sled that I really enjoyed riding, but I can’t help but wonder how much more nimble and playful it might be with a 34″ ski stance.

Big Bore or Turbo Option

In the sledding world, riders are always looking for more performance and power. That’s especially true in the mountain world because of how much the elevation and deep snow steal our power. Some options that would take the Catalyst M 858 Alpha One to the next level in the mountain world would be a Big Bore or Turbo option. Now that the Catalyst M has the 858 engine, it’s not light on power, but it’s always nice to have extra horsepower under the hood.

Handlebars, Grips and Controls

One area of the new Catalyst that’s fairly outdated is the handlebars, grips and controls. They all work fine, it’s just time for a makeover to make this area slightly more modern.

hadlebar and controls on the m 858 alpha one sno pro


The Catalyst platform has been built from the ground up to optimize a lower centre of gravity with Arctic Cat’s exclusive lay down engine design. By having this as the foundation of the M 858 Alpha One, it radiates into every aspect of your ride and experience. When you combine the low centre of gravity of the catalyst with the Alpha One Single-Beam rear suspension, the Sno Pro AC5S adjustable shocks and the new 858 motor, you have one of the most playful and fun sleds on the mountain… the M 858 Alpha One Sno Pro 2025.

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