As I drove the Indy XC 850 onto the trailer after my last ride of the season, I sat listening to the rumble of that big twin idling and then turned the key off. We all know that moment when we have just completed our last ride of the season. My time spent on the 2019 Indy XC 850 had been a winter that started with tons of anticipation for this new Polaris trail performance sled that I call AXYS 2.0. The Indy XC 850 featured a lot of new (Patriot 850 motor, PRO-CC rear suspension and a new tunnel built around a 129” track length) and lot of familiar parts (same bulk head, clutching, front suspension, styling, rider position). Now at the end of the season, had this sled in my opinion lived up to my expectations?
As an engineer, I am a detailed oriented person always analyzing every test sled from a design, manufacturing and process (riding) point of view. The Indy XC 850 as mentioned has a lot of new and old, so this winter season was a lot of fun for me. I was skeptical about this iteration of the AXYS when it was first revealed. Was this chassis going to be as big a step change as the first AXYS was back in 2015 with the (hinged) PRO-XC suspension?
It’s going on 10 years now since the Rush 600 with Pro-Ride hit the snow with that crazy looking rear suspension that intrigued all sledders no matter what brand you’re partial to. The Rush was different from anything we had seen. That first Rush suspension was a progressive rate design meant to bring back the lively feeling of an uncoupled track suspension with an outside the tunnel shock linkage that (progressively) increased the shock speed and got stiffer as the suspension cycled through its travel.
As Polaris continued to refine this concept the AXYS chassis introduced in 2015 brought a major improvement with the Pro-XC suspension. “Rider Balanced Control” was Polaris marketing lingo for placing the operator in the “sweet spot” of the chassis. The PRO-XC suspension with a longer front torque arm was the fulcrum that really stepped up the influence rider position had on handling. The design was so sensitive to your body position that there was a learning curve if you had never ridden one. Shift forward to pitch more weight onto the skis to carve like a champ sled or sit back to wheelie through trail junk and let that big progressive rate coil over shock do its magic. The XCR Switchback version with the 137” Cobra track (in my opinion) is the best version of this PRO-XC AXYS to date. (See SnowTech November 2018 review of the Switchback XCR 800).
Introduced in 2017 the Switchback Assault on the AXYS chassis caught the eye and wallets of many Polaris faithful and competitors. The new uncoupled torsion spring IGX 144 suspension uses the same front torque arm geometry for “Rider Balanced Control”. Combine this with a pull rod activated shock on an uncoupled rear torque arm and this sled behaves very similar to RUSH. The other feature of this very capable suspension located inside the track was the use of a conventional tunnel – as all 144” sleds from Polaris have used. These sleds looked like what a modern sled is supposed to look like. We also now had had all that real estate on the tunnel to carry accessories (bags and extra fuel) that, to this day, is the Achilles heel of the PRO-XC version of the AXYS.
With that said, what would happen if Polaris kept the same front torque arm geometry and combined it with a coupled rear arm? Polaris Engineering thought the same and the result is the PRO-CC suspension which lives inside the track. The spinoff from this design is a return to a conventional tunnel and the benefits and appeal that offers.
Liberty 850 Patriot vs PRO-CC
So, after a full season of riding the 850 I almost wish I had spent the winter riding an 800 H.O. instead to truly appreciate the impact the PRO-CC vs PRO-XC change has made. The 850 with more torque and HP for sure influences how the sled behaves on both smooth and rough trails. As the season progressed my focus for my evaluation moved away from the new 850 to the 129 PRO-CC suspension.
But let’s quickly talk about the 850 Patriot motor. The power and torque enhancements over the 800 H.O. combined with fuel economy and oil consumption on par with the 800 H.O. Whats not to like? Yes, it pulls harder than the 800 H.O. and it walked the speedometer to over 100 mph in no time flat. You’re grinning from ear to ear every time you nail the throttle. Big bore two strokes and carpal tunnel syndrome were for years a given. The engine mounting architecture for the Patriot 850 is all new and designed specifically for this engine. The primary goal was to significantly reduce operator vibration while still maintaining proper alignment of the driveline components and overall durability of the CVT system. Powerful engineering analysis software was leveraged, along with an extensive laboratory development plan. In operation engine vibration transferred to your hands or feet was neglible. I could write an entire article just on the kinematics of vibration and how Polaris worked to control both low frequency and high frequency vibration with this engine. Durability issues? Not on my sled. No PTO bearing failure, no issues with plugged inner oil check valves causing oil lines to pop off. Polaris did offer a re-flash to get rid of a mid-range bog and plug fouling issues, but I chose to stay with the original programming just to see if I experienced run ability issues. I finished the season on the original spark plugs and the sled purred like a kitten.
First year engines (no matter how much durability testing takes place on factory dynos and prototypes) can still have issues when finally turned over to production and put into the hands of consumers. I am not minimizing the fact that a small number of these motors did suffer crankshaft and run ability issues. Social media blew up last winter with negative posts that made you think that every 850 Polaris built had problems. Nothing could be further from the truth. The reality is only a very small number of engines had issues. SnowTech test riders had four Patriot 850s last winter and every one of them performed flawlessly. That said, the 4-year engine warranty Polaris provided is insurance for any issues should they develop in the future. In summary right out of the box the new 850 Patriot lived up to is claim as the most powerful snowmobile engine ever built in Polaris’s 65 years of building sleds. The scary part is that it’s only going to get better in the future.
The bigger news was the introduction of a new (in the tunnel) fully coupled suspension. For the past 10-11 years Polaris has refined the progressive rate Pro-XC suspension on the Rush and Switchback. I knew how good this design worked and questioned if the new PRO-CC could even come close. Polaris had fully-coupled suspensions before, went away from them, and now was going back to them. Really?
So, this past winter I was avoiding table top smooth trails and looking for Sunday afternoon beat up trails. I soon discovered that this was not my old XTRA-10 rear suspension. For sure, the PRO-XC suspension heritage is built into design. The big difference I noticed with the sled because of the coupling was the faster weight transfer back onto the skis to improve cornering. The sled would still lift the skis and wheelie but in a more controlled fashion than with the PRO-XC chassis. Overall the 129 PRO-CC is less sensitive to rider position but still responds much faster than other skid frames. The suspension does respond much quicker to trail chatter thanks to separating the spring motion from shock travel in those first few inches of suspension travel. The Camso Cobra is my favorite track and it worked well in this application. The Walker Evans Piggyback shocks worked flawlessly, mind you the new skid is more cumbersome to adjust the damping on the rear arm shock than the PRO-XC. Minor stuff, but I would really like to see a remote damping adjuster on these shocks.
What would I change? Well, a 137” track length was what I was hoping to see last year. The 129” length of the INDY XC had me puzzled when the 137” Switchback with the PRO-XC was working so well bridging bumps. We all know that wish has now been granted for 2020. The other change is still that chain case intrusion on the right side restricts foot movement. That one we will just have to live with for now, as real estate is so very precious in that exact location.
At the end of the season, the new INDY XC 129 worked so well that I now understand why Polaris went with a different name for this new model. In fact, AXYS 2.0 is what Polaris should refer to the new PRO-CC equipped platform as it truly is the next evolution of the AXYS technology. I can hardly wait to swing a leg over the 2020 XCR version and the INDY XC 137” this coming winter!
By Hal Armstrong – SnowTech Canada