Celebrating 40 Years of Indy
Even though we now have the new MATRYX platform from for 2021, Polaris still has their INDY XC (AXYS) models in their line-up, and for good reason. The INDY XC 129” has only been out for two years and the INDY XC 137” was brand new for 2020!
We ran a pre-production INDY XC 129” with the 850 engine in the spring of 2018 and loved it. For the 2019 model year we ordered an INDY XC 129” but with the 600 engine, loved that sled as well. With the introduction of the 137” version it only made sense for us to order an INDY XC 137” for 2020, which we did. Again, we went with the 600 engine as we like to mix it up with our fleet of test sleds. It’s nice to have a variety of engine sizes and track lengths so we have a better understanding each year of where each OEM is at with their model offerings.
Ever since the 2010 introduction of the Polaris RUSH, Polaris has offered high-performance short track trail sleds with the hinged beaver-tail rear suspension. But with the huge popularity of the Switchback Assault 144” introduced for 2017, it became clear there was demand to take this basic formula and scale it down to the shorter track lengths. So, the INDY XC 129” was introduced for the 2019 model year. Fitted with an outstanding Walker Evans shock package with needle shocks up front, a large 2” diameter center track shock and a Velocity Series needle shock in the rear, the ride comfort and trail performance was well received.
For 2020 Polaris brought us the INDY XC 137” models. Promised to be every bit as good as the 129” sleds of 2019, but now with the longer track and tunnel. This provides even more room to carry gear, a smoother ride, improved flotation and greater stability, all while delivering responsive handling and the ultimate in confidence through a wider range of conditions.
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Not everyone has been convinced, though. The 120” RUSH and 137” Switchback models had been in the Polaris line-up for eleven years, and even with the 2015 introduction of the AXYS platform Polaris decided to keep the hinged rear end on the RUSH and Switchback. The original intent was to be unique and different from the competition. That it did. And through the years, the progressive rate un-coupled suspension evolved and improved. The package was responsive and quite reactive to rider input, but was really dialed in to a specific set of conditions. But, owners of these sleds LOVED them. Anyone with an AXYS sled with the PRO-XC (beaver tail) knows how good they’ve become.
With the INDY XC 137”, what this really amounts to is replacing the hinged rear end on the 137” Switchback with a traditional tunnel and a longer version of the PRO-CC rear suspension introduced in the INDY XC 129”. The PRO-CC rear suspension goes back to separation of the springs and shocks on the rear arm and it goes back to being coupled, for pitch control, weight transfer control and sharing the distribution of the bump energy. Polaris knows this design well as it provides a consistently smooth ride with outstanding acceleration and precise handling through time-tested geometry.
Race-tested and race-proven Walker Evans Shocks have improved clicker accessibility for easier adjustability. The IFS is equipped with piggyback Needle shocks, while the front track shock is a piggyback with a large 2-inch-diameter for fade-resistance, greater durability and improved ride performance. The rear track shock has the industry-exclusive Velocity Series Needle Technology with the piggyback positioned midway on the shock body for a position-sensitive damping curve to provide improved ride comfort and resistance to bottoming.
We had logged well over 3,000 miles on the INDY XC 129” (pre-production and production sleds) so when we were able to get some serious seat time on the new 137” INDY XC we could immediately appreciate the advances afforded by the added track on the ground. First off it hooks up better and gives you better traction, both for acceleration and braking. The tail isn’t as prone to come around with the longer wheelbase, so the stability and confidence is greater. This also gives you less rocking and pitching compared to the shorter track length for a smoother ride. Overall, stability is noticeably improved, tracking straighter and not being as “busy” as a shorter track sled. These are all reasons so many trail riders have been migrating to the 137” length, finding it to be more versatile while almost as quick to respond as a 129” sled. Almost.
If you’re only riding packed trails then the 129” version is excellent, but anytime you need the added capability of the longer track (loose snow, fresh snow, deeper snow) we’ll take the 137” length hands down. The sacrifice in handling is minimal and barely noticeable, as what you gain from the extra length far outweighs the slight reduction in sharp handling response. Smaller riders and those in the tightest of trails would be the ones better suited with the 129” track, but we believe most everyone else would find the 137” to be the ideal combination. We’ve always been big on tunnel-mounted fuel cans and cargo bags, so the added tunnel length is a plus in as it is now easier to carry both a cargo bag and fuel caddy at the same time. Polaris has a host of accessories for these models as well.
Where the hinged progressive rate rear suspension of the Switchback and RUSH models had the coil spring on the rear shock, the INDY XC goes back to a coupled design with torsion springs. This is where the INDY XC 137” surprised us after our 2,100 miles last winter. Right out of the crate it had what we would call excessive ride sag – it was too soft. Unless you were under 200 pounds we could not get the proper ride height out of the rear suspension. Cranking the torsion springs all the way to their highest setting just wasn’t enough preload. It seemed like we didn’t have enough pre-load or spring rate, that the springs were sagged like they had 5,000 miles on them. It was a head scratcher.
We referenced both the owner’s manual and parts catalogs only to discover the 137” version of the PRO-CC suspension were delivered with the exact same torsion springs as the 129”. Traditional thinking is when you add length to the rails you add leverage so the shock and spring combination will act softer if left with the same geometry. Granted, the Velocity Series rear track shock and the progressive geometry does an excellent job at filtering the stutter bumps, giving you good shock stroke in typical riding, but without adequate ride height we lost our resistance to bottoming at full stroke (this is where the needle shock typically excels, at full stroke it is more difficult to bottom it out).
We checked with some Polaris dealers and they were hearing the exact same complaints from their riders with the INDY XC 137”, especially the ones over 200 pounds. Many riders who had come from one of the beaver-tail sleds found the new INDY XC 137” to be much softer than what they had, squatting on acceleration, light on the skis, and unable to adjust it. Not being able to get the heavier springs just added fuel to their complaints. Some riders tried to compensate by cranking up the compression damping on the rear shock, but this will only do so much as a large amount of the shock stroke has been used with the ride height being so low. It’s like having a suspension with only half the travel it’s supposed to have.
Just like any other time in the past 30 years, if we have a sled that we can’t set for our weight we order a set of stiffer torsion springs. This is the correct way to solve this problem. It made sense as the longer rails added leverage, and with the same springs as the 129” we didn’t flinch at the logic. Of course, the heavier torsion springs were on back order so we knew it was an issue. But, when we later talked to one of our friends at Polaris that does calibration testing on new models he told us he was unaware of what we were asking about, so that just added to the confusion.
Our hope is they have all this sorted out for the 137” MATRYX models. We should add when we ride the pre-production test sleds in the spring they do NOT have a problem with light springs, this is only something that surfaced with the production units. We do our best to tell you how good the new sleds perform, but what is built and sent to the dealers sometimes differs in exact calibration. This is why we place such great emphasis on our thousands of miles of testing actual production sleds instead of putting all of our marbles on the pre-production photo units.
Even with the proper torsion springs installed for the rider weight, one must realize the INDY XC is still more of a trail sled. If you’re a hard-charging higher-speed ditch runner then the XCR models will deliver an even more appropriate shock package with firmer valving and spring rates, better equipped for higher speed bigger bump capability. The XCR still comes in two forms; the 129” is on the INDY XC platform, where the 137” version is a hinged Switchback that works extremely well.
Past that, we have really liked our time on the INDY XC sleds the past two (two+ years with the pre-production unit in 2018), both the 129” and 137” versions. The riding position is neutral and doesn’t constantly force you forward with the flat and level seat. Compared to the Gen4 Ski-Doo and now the new MATRYX the AXYS body panels hold you back in place, but you really don’t notice it unless you swap back and forth. What remains the same is how the Polaris front end is very forgiving. The variable caster is the magic here as the spindle angle is relaxed as the suspension compresses, in effect lengthening the wheelbase and giving the sled its predictable nature.
The running quality of the Liberty 600 engine was again as expected. This has been a really good engine for Polaris for many years. Yes, the transfer-port injection 2-stroke has no electronic control for the power valves and it is getting long in the tooth compared to the likes of the second-generation E-TEC 600R from Ski-Doo, but the two remain very close in terms of all-out performance and most every other metric. The Rotax engine is quieter and better on fuel and runs smoother, we admit that, but we still like the Polaris 600 engine. It never misses a beat, always runs the same and never lets us down. And, it is light, allowing the sled to be agile and responsive.
Our test sled ended up with 2,105 miles by the time we were shut down last March. Pretty much every time it went out it was with the Ski-Doo Renegade X 600R, so we had two 600s with 137” tracks to run groomed trails with. When the deep snow came we went with our 144-146” sleds to better match the conditions. Slowly over time the 137” sleds have become more of a trail sled and less of a crossover sled. They can still go on the rides with the 144-146” sleds, you just don’t want the 137” to be breaking trail. In deeper or fresher snow they will have to run at a higher rpm to keep up and thus will use more gas and oil per mile, or day, of riding. You have to use more throttle to keep up, it’s that simple.
For the most part we ran the sled stock as there was little need to deviate. We added the LinQ Adapter from Up North Technologies simply because it allows us to carry two accessories instead of one and it allows us to carry the LinQ Fuel Caddy, something we value highly (but had to leave empty with our heavier riders). We added the excellent Polaris accessory windshield (#2880394) for added protection as many of our test riders are tall and appreciate the added protection during our hundreds of miles in cold conditions at high speeds. We ordered this sled with the Storm 1.5” track which we really like. It is more durable than the Cobra 1.6 and has stiffer lugs so it works better on packed trails, but still performs quite well in the fresh snow that we have so frequently. The 600 didn’t seem to have any issues spinning it or having to run at a higher rpm to keep up. No damage to the track after 2,100 miles, wear was negligible. You can tell the rear end is hooked up better than say with a RipSaw I or Ripsaw II track, in cornering, straight line and braking situations across the board.
Durability and reliability was flawless. No fouled plugs, no blown drive belt, replaced the carbides, no hyfax replaced. Tension the chain, tension the drive belt, tension the track, add gas and oil, go ride. As it should be. We really liked the INDY 40th Anniversary graphics as we still remember the very first INDY 340 we had back in 1980 as one of our Race & Rally Magazine test sleds. That exact sled is still in our area, having been combined with another sled to make a running unit, but it still exists after 40 hard years! That is what we expect from a Polaris – long term durability.
By Kevin Beilke