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2025 Arctic Cat M 858 Mountain Cat Alpha One 154 2.6 ES
2025 Arctic Cat M 858 Mountain Cat Alpha One 154 2.6 ES

Specs

General Information

Manufacturer
Arctic Cat
Arctic Cat
Model Year
2025
2025
Model
M 858 Mountain Cat Alpha One 154 2.6 ES
M 858 Mountain Cat Alpha One 154 2.6 ES
Model Code
S2025CMJSMUSL
S2025CMJSMUSL
Color
Skye Blue / Galaxy Blue
Skye Blue / Galaxy Blue

Dimensions

Length
Overall chassis - 126.5 in.
Overall chassis - 126.5 in.
Height
Overall chassis - 50 in.
Overall chassis - 50 in.
Width
Overall chassis - 42 - 44 in.
Overall chassis - 42 - 44 in.

Engine & Drivetrain

Engine
858, 2-Stroke
858, 2-Stroke
Cylinders
2
2
Cooling

Liquid

Coolant System Capacity - 4.2 qt.

Front / Short tunnel heat exchanger

Liquid

Coolant System Capacity - 4.2 qt.

Front / Short tunnel heat exchanger

Displacement
858 cc
858 cc
Bore x Stroke
3.3 x 3 in. (85 x 75.6 mm)
3.3 x 3 in. (85 x 75.6 mm)
Fuel System
Next Gen. C-TEC2
Next Gen. C-TEC2
Starting
Push-Button electric
Push-Button electric
Ignition

Digitally Controlled CDI

Engine Stator Output - 270W @ 3,000 rpm

Digitally Controlled CDI

Engine Stator Output - 270W @ 3,000 rpm

Lubrication
Electronic Injection
Electronic Injection
Drive System
AC M Belt Drive
AC M Belt Drive
Drive Clutch
ADAPT
ADAPT
Driven Clutch
ADAPT
ADAPT
Drive Sprocket
9 Tooth, 2.86 Pitch, Exvolute
9 Tooth, 2.86 Pitch, Exvolute
Clutch Calibration
6,000 - 8,000 ft.
6,000 - 8,000 ft.
Reverse
Push-Button Engine
Push-Button Engine
Transmission

Gearing - 24 / 63

Chain pitch - Belt

Gearing - 24 / 63

Chain pitch - Belt

Exhaust
APV IV with Full Stainless Steel Exhaust and EGT Sensors
APV IV with Full Stainless Steel Exhaust and EGT Sensors
Brakes

Disc

Stealth Hydraulic Master Cylinder

Disc

Stealth Hydraulic Master Cylinder

Fuel Type
Minimum Octane - 91
Minimum Octane - 91
Fuel Capacity
10.4 gal.
10.4 gal.
Oil Capacity
3.0 qt.
3.0 qt.

Operational

Handlebar
Hooked with grab handle
Hooked with grab handle
Instrumentation

Arctic Cat G8 (CAN without GRR) gauge

Speedometer, tachometer, odometer, fuel, oil, clock, battery voltage, altimeter and hours - Digital

Coolant - LCD Icon

Arctic Cat G8 (CAN without GRR) gauge

Speedometer, tachometer, odometer, fuel, oil, clock, battery voltage, altimeter and hours - Digital

Coolant - LCD Icon

Seating or Rider capacity
Mountain
Mountain
Skis

Type - G2 ProClimb

Width - 7 in.

Type - G2 ProClimb

Width - 7 in.

Ski Stance
35 - 37 in. adjustable
35 - 37 in. adjustable
Carbide
Runner type - Single runner with Carbide
Runner type - Single runner with Carbide
Track Type
PowerClaw
PowerClaw
Track LxWxH
154 x 15 x 2.60 in.
154 x 15 x 2.60 in.
Pitch
2.86 in.
2.86 in.

Other

Includes
12V Outlet, Integrated Goggle Holder, ATACH Rear Storage, Hand and Thumb Warmers, Ice Scratchers, Vertical Steering, Tether Switch, Visor Plug-Ins
12V Outlet, Integrated Goggle Holder, ATACH Rear Storage, Hand and Thumb Warmers, Ice Scratchers, Vertical Steering, Tether Switch, Visor Plug-Ins
Safety Features

Lighting - LED

Sport Front Bumper

Lighting - LED

Sport Front Bumper

Warranty
Factory - 12 months (In-season), 24 months (Pre-order)
Factory - 12 months (In-season), 24 months (Pre-order)

Suspension

Shocks

Ski / Front Track - FOX FLOAT 3 QS3

Rear Track - FOX FLOAT 3 QSL

Ski / Front Track - FOX FLOAT 3 QS3

Rear Track - FOX FLOAT 3 QSL

Front Suspension

AWS 36

Travel - 7.6 in.

AWS 36

Travel - 7.6 in.

Rear Suspension

ALPHA ONE

Travel - 14.5 in.

ALPHA ONE

Travel - 14.5 in.

Features

Features

  • A BREED OF POWER - ALL 858 ENGINE: The 858 two-stroke engine is designed for seamless integration into the CATALYST platform. With an 8% increase in displacement, this engine houses an 11% increase in output over the C-TEC2 800 and weighs 4% less. It features an optimized air intake system, a exhaust valve design for more consistent power and cleaner emissions, and a crankcase for increased stroke and integrated engine mounts.
  • PEAK PERFORMANCE UNLOCKED - CATALYST CHASSIS: The revolutionary CATALYST platform has been built from the ground up to optimize every aspect of your ride, so much so that you’ll feel at one with the sled. With enhanced ergonomics, a lower center of gravity, our exclusive laydown engine design, specially calibrated suspension and more, this changes everything.
  • NAVIGATION AT YOUR FINGERTIPS - ARCTIC CAT G8 DIGITAL DISPLAY: The Arctic Cat G8 digital display, powered by Garmin, offers seamless integration with your sled. A built in GPS with preloaded trail maps, customizable data fields and phone connectivity are just some of the features that make G8 essential for every ride. Plus, the group ride functionality utilizes satellite or celluar data, dependent on region, to share the ride with up to 15 people.
  • OPTIMIZED FOR DEEP SNOW - AWS 36 FRONT SUSPENSION: The AWS 36 Front Suspension was designed specifically with the M 858 Mountain Cat in mind. With lightweight spindles and precision engineered geometry, this suspension system optimizes your performance in deep snow.
  • INCREASED DURABILITY - ARCTIC CAT MOUNTAIN BELT DRIVE: The CATALYST platform utilizies Arctic Cat's belt drive system rather than a chain drive. This allows for enahnced durability and fewer parts in the system. The adjustable center distance allows for multiple ratio options and makes servicing simple.
  • UNPARALLELED VERSATILITY - FOX FLOAT QS3 SHOCKS: ALPHA ONE suspension is easily adjustable for ride and intensity with FOX FLOAT® shocks: from the three-position QS3 on the ski and front arm, to a semi-locking QSL on the rear, you get easy adjustability for maximum deep snow performance.
  • QUICKLY CONNECT - ATACH LATCHING SYSTEM: Adding accessories to your sled is a snap with this 4-point latching system. You can install and remove accessories in seconds, so no matter where you are, you can customize your sled with ease.
  • UNMATCHED CONTROL - ALPHA ONE SINGLE-BEAM REAR SUSPENSION: Arctic Cat’s revolutionary single-beam rear suspension changes the game for mountain snowmobiles. The unique monorail design sheds snow to keep your sled light and equalizes floatation across the width of the track. ALPHA ONE offers enhanced maneuverability, giving you tighter turns than ever before.
  • BRIGHTEN ANY RIDE - ASYMMETRICAL LED HEADLIGHT: A premium LED headlight is crucial to optimize your visibility. Equipped with both high and low-beams, this headlight casts an LED light pattern with great range and width. Plus, with its unique asymmetrical design, everyone will know that you're on an Arctic Cat.
  • SMOOTH POWER DELIVERY - ADAPT CVT SYSTEM: With its lightweight, narrow design that increases performance and belt life, as well as the industry’s only self-adjusting clutch, the ADAPT™ CVT system provides better throttle response, smoother power delivery and a ride like no other.

Features

  • A BREED OF POWER - ALL 858 ENGINE: The 858 two-stroke engine is designed for seamless integration into the CATALYST platform. With an 8% increase in displacement, this engine houses an 11% increase in output over the C-TEC2 800 and weighs 4% less. It features an optimized air intake system, a exhaust valve design for more consistent power and cleaner emissions, and a crankcase for increased stroke and integrated engine mounts.
  • PEAK PERFORMANCE UNLOCKED - CATALYST CHASSIS: The revolutionary CATALYST platform has been built from the ground up to optimize every aspect of your ride, so much so that you’ll feel at one with the sled. With enhanced ergonomics, a lower center of gravity, our exclusive laydown engine design, specially calibrated suspension and more, this changes everything.
  • NAVIGATION AT YOUR FINGERTIPS - ARCTIC CAT G8 DIGITAL DISPLAY: The Arctic Cat G8 digital display, powered by Garmin, offers seamless integration with your sled. A built in GPS with preloaded trail maps, customizable data fields and phone connectivity are just some of the features that make G8 essential for every ride. Plus, the group ride functionality utilizes satellite or celluar data, dependent on region, to share the ride with up to 15 people.
  • OPTIMIZED FOR DEEP SNOW - AWS 36 FRONT SUSPENSION: The AWS 36 Front Suspension was designed specifically with the M 858 Mountain Cat in mind. With lightweight spindles and precision engineered geometry, this suspension system optimizes your performance in deep snow.
  • INCREASED DURABILITY - ARCTIC CAT MOUNTAIN BELT DRIVE: The CATALYST platform utilizies Arctic Cat's belt drive system rather than a chain drive. This allows for enahnced durability and fewer parts in the system. The adjustable center distance allows for multiple ratio options and makes servicing simple.
  • UNPARALLELED VERSATILITY - FOX FLOAT QS3 SHOCKS: ALPHA ONE suspension is easily adjustable for ride and intensity with FOX FLOAT® shocks: from the three-position QS3 on the ski and front arm, to a semi-locking QSL on the rear, you get easy adjustability for maximum deep snow performance.
  • QUICKLY CONNECT - ATACH LATCHING SYSTEM: Adding accessories to your sled is a snap with this 4-point latching system. You can install and remove accessories in seconds, so no matter where you are, you can customize your sled with ease.
  • UNMATCHED CONTROL - ALPHA ONE SINGLE-BEAM REAR SUSPENSION: Arctic Cat’s revolutionary single-beam rear suspension changes the game for mountain snowmobiles. The unique monorail design sheds snow to keep your sled light and equalizes floatation across the width of the track. ALPHA ONE offers enhanced maneuverability, giving you tighter turns than ever before.
  • BRIGHTEN ANY RIDE - ASYMMETRICAL LED HEADLIGHT: A premium LED headlight is crucial to optimize your visibility. Equipped with both high and low-beams, this headlight casts an LED light pattern with great range and width. Plus, with its unique asymmetrical design, everyone will know that you're on an Arctic Cat.
  • SMOOTH POWER DELIVERY - ADAPT CVT SYSTEM: With its lightweight, narrow design that increases performance and belt life, as well as the industry’s only self-adjusting clutch, the ADAPT™ CVT system provides better throttle response, smoother power delivery and a ride like no other.