Totally Trail!

Two 850s and an 800 square off with new suspension tech
2019 Polaris Rush Pro S 850
2-stroke twins are in!

Big twin cylinders have been around for a while, but the hulky 2-strokes are getting even stronger, faster, more efficient, quieter and more reliable. The days of carbs and pre-mixing fuel in performance trail sleds are long gone. To get a seat at the “top trail sled table” you almost have to have 165+ hp or another trick up your sleeve. All three of the sleds in this comparison article are unique from motors to suspensions.

Here we take a look at the new Polaris 850 Rush Pro S, the Ski-Doo MXZ X 850 and the Arctic Cat ZR 8000 Limited with iAct. Each of these sleds looks different, offer exclusive features and attack the trail in their own way. Here’s what we found in our testing!

■ Polaris shoots and scores with new Pro S 850
Boasting 7% better power-to-weight and 9% better acceleration than others (as far as strictly the motor is concerned) are bold claims, but having extensively tested numerous pre-production models in varying market segments, any version of sled with this 850 motor is impressive. We’ve got lots more insights into this power-plant in our Tech Notes section on pg. 40

In our own side-by-side acceleration testing, this new 850 is right with the Ski-Doo MXZx 850 in nearly every test. From a short 330 feet to over ½-mile the two 850s on the market are almost too close to call. We have done everything from switching riders, to switching start areas, to GPS and things are incredibly even. Without our newest high-tech radar and a consistent track there is no way to be definitive yet, but don’t worry - we will have all that info for you later in the season … so stay tuned!
As of now, our tests show the new Rush 850 Pro S to be every bit as fast as initially claimed, but it works differently in different chassis. Polaris is upping the suspension capability of their Indy sleds and putting out more machines with a standard tunnel, and obviously putting more resources on sleds that are NOT of the Rush variety. So we discussed the possibility that this Rush sled might not get the attention, be dialed in, and therefore not perform as well as the Indy with the new 850.
We were wrong. The Rush Pro S is still a fantastic trail sled. It handles corners with precision, staying flat even when dicing a super tight turn. The Rush has been refined since 2010 when the first 600 sled was introduced and now the AXYS chassis with balanced control and active rider positive feedback allows the person riding an 850 to get max performance from this machine. Throw a leg out, this one responds … lean back and hammer the throttle and transfer is naughty-fun … jump a 20-foot road approach and it seems boringly easy.

The small challenges we have with the Rush are things that we have said for years, nothing to do with this incredible new motor (at least not that we know of yet). But face it, a four-year motor warranty for any motor, SnowCheck or otherwise, is awesome. We are not worried about the engine, we think Polaris did their homework there. For even more info on the motor, check out our Spring issue 2018 pg. 32 and our website.
2019 Ski-Doo MXZ X 850
Our favorite track for this sled is still the 1.35” Cobra, but at just 120 inches long there isn’t the footprint that most of the sleds in this category have now. A 129-inch track is pretty much standard issue for most trail sleds now, because that length strikes a balance between grip in acceleration and stopping, but also smoother handling in all kinds of bump-bridging scenarios. The awkwardly spaced big bumps are really the only place where this sled falls short of some of the competition.

SnowCheck 850 sleds offered your choice of all kinds of goodies, but select in-season models straight from Polaris also offer tons of color options to really customize your sled. Panels, seats, hoods, spindles, ski loops, rails, tunnels and more can all be customized this year on certain Polaris sleds. We have mentioned this before, but Polaris is a step ahead of everyone in this customization category.

Other than the motor and colors, this is the same sled from 2018. It has all the same stuff we loved last year like LED headlights (we will say again that ALL snowmobiles should have these standard) and optional Interactive Digital Display. Connect your iPhone via Bluetooth for calls or texts, and use the GPS and mapping capabilities without having to mount a separate cumbersome GPS unit or make retrofits to your dash to make an accessory fit correctly.

■ Ski-Doo has a head start
It’s true, Ski-Doo was the first to get back into the bigger twin-cylinder 2-stroke game since Polaris axed the old 900 Fusion. This is the third model year of their second generation E-TEC 850 so they have had some time to refine. There are many differences between this 850 and the Polaris 850 including different ideas on bore and stroke compared to each other. More importantly though were the leaps that both Polaris and Ski-Doo took when compared to their most recent 800s. Each company took a different direction moving up to the 850 class from their 800s. (Again, see Tech Notes for a little more on this.)

It is more than just the difference between direct injection in the Rotax-made Ski-Doo E-TEC and more semi-direct injection in the Polaris made Patriot CFI. Ski-Doo has been on a specific path for a while with their engine families and that is the real head start.

Ski-Doo’s E-TEC 2-stroke program and their ACE 4-stroke program are forward-thinking engine programs. They are ahead of the competition in many ways. Both of the family trees of these engines have roots in other motorsports applications and have been updated, changed, modified and repackaged across all kinds of different lines from side-by-sides to watercraft. The Ski-Doo 850 motor is the newest in a line of direct-injected 2-stroke twins that have helped revitalize consumer excitement about the longevity of the 2-stroke motor across several powersports applications.
2019 Arctic Cat ZR 8000 Limited iAct
The MXZ X 850 we are talking about here is arguably the best all-around trail sled Ski-Doo makes. This is a spring-buy sled that really hits that sweet spot on price and capability. The X is not the Snocross race-ready X-RS, nor is it the in-season Blizzard model or the more tame TNT. But just because you won’t see this exact model being tossed 60 feet in the air on the Snocross circuit, this sled is more than capable of devouring a heaping serving of nasty moguls. Let’s not forget that the HPG Plus shocks on this are some of the best shocks you can get before adding reservoirs, and the KYB Pro 36 rear shock would have been deemed a full on Snocross shock just a couple years ago.

Moving up from the 800 to 850 we noticed the quicker response in the pDrive primary clutch, but what we really enjoyed was that even though the response was quicker, the 850 was still easy to drive. Often times when OEMs up the power they don’t clutch accordingly to enable the soft feel, easy engagement and ride-ability for more than just the risky racer types. Possibly the greatest aspect about this sled is that it is crazy fast but not jerky, downshifting is smooth, and this makes cornering and bump-riding that much more enjoyable.

Things we particularly like on this sled include the forward adjustable handlebars. I would put these on crossover sleds too, but many of our test riders debate me on this. Since I am not as tall as others I don’t need a huge riser unless we really get in some technical off-trail stuff and I need the leverage. But this is a trail sled, so I digress. We also think the rMotion suspension is still one of the best trail suspensions, overall, in the industry.

Things we don’t particularly like on this sled include the super skinny and fairly hard seat. The old X-seat was the gold standard, we thought, and this was a big downgrade on comfort. It may be a little easier to maneuver around, but it’s not great after 250 miles in one day. We would also take the 5.7 Pilot skis, not the adjustable skis, if it were our money.

■ Cat’s newest suspension tech
The iAct is just one of two new suspension advances that Arctic Cat unveiled for 2019. The Alpha One mono-rail rear suspension was laser-sighted into the mountain machines and the new iAct pinpointed the trail riders. Shock maker Fox hooked up with Cat again to build on previous OEM shock reveals including the Float shocks, more recently the QS3 shocks, and now the iAct system. Taking a cue from the QS3, the iAct has three positions (soft, medium, firm) that can all be adjusted manually very quickly. However, instead of the manual clicking, the iAct is all electrical with just the press of a toggle on the left control block on the handlebars that allows you to see which setting you are in on the dash. Pretty slick and adjusting takes milliseconds!
The Zero IQS coil-over piggyback gas shocks are wired along specifically tested routes to the electrical harness so as to minimize possible damage from debris, or collision. The front shocks are 1.5 and the rear is a 2.0. It won’t be long, we think, until you will be seeing 2.0s for all the shocks for the added capability. All but the center shock are adjustable with the on-the-fly system, and all are adjusted to the same setting. You cannot adjust the two front ski shocks and the rear shock independently or separately with this system, and the center shock is a Cat IFP, so the spring preload needs to be adjusted manually with the help of tools. We are guessing the fourth shock will be adjustable for MY2020 and that all the shocks will be independently adjustable soon as well. We think this is important because the hardest shock to adjust and get right is the center shock. It is near impossible often times to do on the trail once the skid is iced up, so being able to do it with a toggle on the dash would be fantastic.

We had a clue something like this was coming after our meeting with Fox reps at Hay Days six months prior to the release of the technology so we had plenty of time to discuss the system before we rode. Sometimes that is a good thing and a bad thing as you can get preconceived ideas in your head as a test rider. But all the thoughts were quickly washed away once we got on the new ZR 8000 Limited. We all agreed it was a big step in a super positive direction. Again, we think that it is important to have all four shocks be adjustable with this system ... can we drop any more hints?

Now you can only get this system on the Thundercat/9000 or ZR 8000, 7000, or 6000 Ltd and it is an $800 add-on to go from a regular limited sled to a limited with the iAct. That’s not chump change and the sled we rode was $14,799. But how does it actually perform on the trail? Like a dream!

We spent plenty of time on separate occasions ride-testing both the black and the new purple plastered ZR 8000. The bump capability is very good, but we found that dialing in of the suspension in the medium setting worked even better for cornering. The medium setting is obviously going to be the most used setting for the most amount of riders most often, but being able to adjust on the fly when you slow down in front of a rough mogul patch is a great convenience. We would simply slow down to a crawl, make sure we switched setting correctly, then get back into the throttle. That saves lots of time and a lot of headaches versus getting off your sled, getting tools out, chipping away ice, adjusting several shocks, putting away the tools and going again.

The new controls, push button electric start, and a tether are all long overdue and we hope that all sleds will have them on them in the near future.
■ Our decision
The Ski-Doo MXZx 850 has great ride-ability and performance in all trail conditions. Resale recently has also typically been higher for these. That might change though with the new Polaris 850 holding its value, as well as the ZR 8000 with the iAct. Also, we think the overall best value is the Polaris 850 which had a four-year warranty on the motor. Ease-of-use honors go to the ZR 8000 with iAct for sure. But if it were my own money, I think I would want to try the Polaris 850.
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