Catalyst M 858 review (part 1) - The SnoWest Show

The SnoWest test crew of Justin Stevens, Rhett Clark, Bruce Kerbs and Broc Genta join Ryan Harris to review our first three days on the 2025 Arctic Cat M 858 sleds.

[arcticcatrider]

Weird a show sponsored by polaris doesn't like an Arctic cat product

[shanegerwing]

Not that anyone wants to start thinking about modifications to a new $20k sled, but it seems many will! I ordered a M858 MC154 QS3 ES. I swap out a Lithium Battery, loose 7lbs, loose another 13-15lbs in a Speedwerx L2 silencer, hopefully loose about 1.5 lbs rotating mass with Ti clutch components, Speedwerx clutching, I'm sure that bottom end will wake right up. I love my Ctec800 Speedwerx Stage 2, it's an absolute ripper from bottom, mid, and top! If I could just transfer that power/response/reliability to the newer/lighter Catalyst chassis I'd be super happy!

[barryconnors-ms]

I was always a doo guy but I hope cat gets it dialed in cause man it would be so sad to lose another brand

[simengreen]

The two pull start is probably just a prototype thing, I pull twice in the morning, to wake the fuel system or something on my 800, one pull the rest of the day. And all the talk about sloppy bottom end, its not a production sled, so much can change.. Did you ride the sno pro? How was the AC5S shocks?

[jeffb]

They should not be sponsored by Polaris, Cat or Doo if they are doing reviews. Talk about conflict of interest. And I am not even a CAT guy....

[go-on-two]

This was another strange review, seemed like nobody was willing to really step up and talk about the handling because they didn't want to bash any more after how they all didn't like the engine and clutching, but they did allude to the fact it didn't feel as light as the 600 and then went on to say its the best Mountain sled AC has ever put out...Something is not right here, not sure if Poo threatened to pull funding or not!!! But it did seem somewhat political, with very uncertain comments.

[caseynelson]

Saddened about the bottom end. The polaris 850 bottom end is soft compared to the 800. If the 858 is even worse, i don't want it.
Hopefully, they can clutch it and get the bottom end equal to the 800's.

[Longtrack]

Had to go back and listen to last years 600 Catalyst podcast and these guys gushed with excitement and seem to love the Catalyst, that podcast was sponsored by Pure Adrenaline Motorsports. After listening to the 858 podcast its basically a POS which just so happens to be sponsored by Polaris. HUH! I cant be the only one that's not surprised by this. When you start the podcast off with Polaris as a sponsor then go into detail that you guys are cat guys (or were are at some point), it still doesn't give you any credibility. Don't bite the hand that feeds ya. Conflict of interest much. I hope Muskoka gets a new 858 he'll put it to the test. It may turn out that the 858 is a bucket of bolts but at least we'll get to see it in action. His channel is the new snowmobile media...snowest can the way of the dinosaurs.

[erikmoore]

It sounds like an honest review to me. strange talk about stroker motors not having as much low end seemed a bit odd.

[vintagearcticcatsnowmobile]

Disappointing you guys are riding prototypes that change before production, but are blasting the new 858 sled, and finally 19-minutes you state there are prototypes and typically change for production. You come across as very poorly organized and unprepared.

[jeffb]

Not sure why you would compare 858 to 9R. Just did a quick build comparison between 9r and 858 ATAC, 155, 3inch, no electric start. $3155 more for 9R. Summit Expert X Turbo with shot is $694 more than 9R for comparison.

[erikmoore]

Makes you wonder if that's steel spider will be changed in the future.

[BFish]

Very strange pod cast and discussion. Mood seemed off, information seemed restricted. Couldn’t get off the engine topic after asking the public what to talk about. Chassis and shocks woulda been nice to listen about. Also it’s not a secret that cats been working on stuff as the sleds were very doggy in the video’s shared at the beginning. The 146 model that Mav has been riding is a great example, it is not the same sled anymore.

[TerraAlpsRacing]

Saying the 858 is soft on the bottom end compared to the others is because the 858 is a production engine built more for emissions. The 9r polaris is built for throttle response for the hill climb racers to have an advantage getting around the flags, course riding. As polaris has more funds going to specialty sleds and classes. TerraAlps Racing will have a performance package to build quick throttle response and acceleration like the polaris and doos. Coming from engine component, ecm tune and a muffler.

[lemoneleven]

how much money do you have to spend on the monorail for it survive a simple trail ride up the mountain?

[brandonmichaelis]

Cat will get the clutching dialed and wake these up. If not, the aftermarket will. I ordered a 154" Black. Super stoked!

[snopro]

Great job on the reviews from everyone.

It is my opinion, Polaris has set the bar with the 9R snap regardless of cc.

And anything 800cc and up NA currently is going to be (frustrating) automatically a unethical compare. And that affects the expectation levels of performance of this sled/motor package immensely.

Great job to all 3 company’s building these things

[jamesmartens]

Geez Louise.... was the word from the polaris sponsor, hey guys just spend 40 minutes talking about the lazy bottom end and nothing else. Almost nothing about the actual chassis or the gauge or the ergo.

[erikmoore]

The etec has a longer stroke than both of them.

[erikmoore]

Start at the 8 minute mark if you want to save a bit of time.