Experiences, Observations and Realities
For the 2024 season, I had the opportunity to experience Polaris’ return to the four-stroke snowmobile market. Throughout the season, one thing became undeniably clear: with the ProStar S4 INDY XC, Polaris now offers a four-stroke engine option that is smooth, quiet and reliable. And with it, a new line of S4-powered snowmobiles that allows snowmobilers to be filled and rejuvenated by the unique beauties of winter wonderlands.
For a complete picture of the goals and focus of my ProStar S4 INDY XC long-term testing, I invite you to read my Preseason Analysis and First Impressions articles. If you read them, you will know that my review of this sled was to be a lesson in objectivity. My goal was to keep my expectations and observations tempered by the realistic targeted market of this model. Well, these proved to be more of a personal challenge than originally anticipated.
The Power of the ProStar S4 Engine
In a Snowmobile world dominated by higher horsepower performance and choices, the reality is that the ProStar S4 engine boasts 90+ hp. Even 600 cc to 650 cc two-stroke models are easily within the 120+ hp range. In the immortal and often repeated words of a loved and departed friend: “It is what it is.”
The Polaris ProStar S4 engine is fuel-efficient, quiet, reliable and touring-calibrated. The enhanced four-stroke life expectancy and savings of no oil to add and regular fuel capability are undeniable.
The S4 offers impressive take off torque and get-up-and-go response at lower speeds. And it is easily capable of maintaining respectable, responsible trail speeds. In premium, hard-packed, downhill, wind-at-your-back trail conditions, the top speed of this machine can be impressive.
I have a geographic location privilege, which allows me to practise the sport we love in some of the Snow Belt’s coldest environments. This makes cold-weather starting very important.
The ProStar S4 was impressively successful in all cold morning starts. However, you must activate the brake to start it. In colder conditions, this can result in not enough hands to hold the brake, turn the key and give it a little gas. A simple solution is to engage the parking brake. Just don’t forget to disengage it.
Polaris’ Exclusive TS Shocks
The TS shock package is Polaris’ newest entry into the world of snowmobile shocks. It is a five-position adjustable shock package that was unique to Polaris and its S4 models for 2024.
Many snowmobilers have become familiar with three-position and 20-position adjustable models. At the beginning of my trial with this ProStar S4 INDY XC, I believed that the five-click TS package had the capability to be, like Goldilocks said, “just right”.
In my season-long trial, I personally found that the first setting was extremely soft and the fifth was very firm. My reality was that, for most any ride circumstances encountered, the TS shocks were realistically equal to having only three positions of usable adjustability. Within these three positions, I found them to be consistent in their motion dampening performance without fade. With the TS shocks, a comfortable and smooth trail ride, or any distance easily awaits.
Perhaps future TS calibrations will yield a more usable five levels of adjustment. If Polaris called it a three-position adjustable shock, I would have called the TS a total win!
A Big Question: Does the ProStar S4 INDY XC live up to its heritage?
My review was not only of the ProStar S4, but also of it being offered as an INDY XC model. Polaris’ XC line-up has always had a reputation for higher trail-targeted suspension performance and calibration. For this sled to meet these expectations, it would need to clear a few challenges.
As previously detailed, the S4 power platform is 90 lb heavier than a comparable 650 cc model. This is definitely a hurdle to meeting the XC characteristics that we have come to expect from Polaris.
The geometric realities of centralized-mass snowmobiles place much more of the vehicle’s weight over the front arm of the rear suspension. The increased weight of the 998 cc ProStar S4 therefore exerts an even greater pressure on it. This has always been the challenge of modern four-stroke-powered snowmobiles, and this one is no exception.
In lower to moderate trail speed conditions, this reality seems minimal. Conversely, at higher speeds, or in softer on- or off-trail riding environments, it is more noticeable.
Standard equipment on the ProStar S4 INDY XC is dual carbide runners. In typical groomed trail conditions, the dual runners offer a predicable steering response with minimal rider input effort.
In softer, deeper, fresh snow conditions, I felt that the lack of deeper carbide runner penetration resulted in occasions of oversteer (push) conditions.
In an attempt to minimize this sensation, I changed the dual carbide runner to the more aggressive 6 in. RUSH Polaris ski runners from Qualipièces. I found that, for me, this change made the steering effort more positive and predictable in soft conditions, without resulting in any significant or detrimental darting effect in harder trail conditions.
Future Calibrations?
I experienced an unwelcome condition with my S4 INDY XC in the throttle response and recovery calibration. When quickly releasing the throttle, then aggressively getting back into it, the motor would significantly lag before returning to life. It wasn’t a bogged down, back shift or TPS-related sensation, however. It was more of a drop-off in throttle response. I typically noticed this during tight or abrupt cornering in the trail with more aggressive throttle modulation. Sometimes, I have also encountered this phenomenon while approaching road crossings. Although I did not read about this anywhere else, I have learned that other test riders with S4 models had a similar experience in higher-performance conditions.
My last visit to Laquerre’s Powersports confirmed that the throttle position sensor (TPS) calibration was correct. So, this condition remained a mystery without any comment, re-flash or calibration offered by Polaris. To be fair, this only happened in more aggressive situations, which, I believe, are likely outside the realistic operating ranges of the targeted demographics.
Again, Does the ProStar S4 INDY XC live up to the XC heritage?
In my opinion, and logically so, the 90+ hp, additional weight, and weight distribution challenges of the S4 package do not currently align it with the Polaris XC expectations. If pushed beyond its impressive calibration comfort zone, the suspension geometry capabilities can be overcome by the additional centralized weight. I believe that it is likely that buyers familiar with XC models would be less than fulfilled by its current ride quality and performance characteristics at higher levels of operation.
With that said, I believe that it was an unfair expectation to hold the ProStar S4 INDY XC to these standards. While the XC question is what many of you wanted to know, and a stated goal of my trial, I learned much more than that.
What I Really Learned With the ProStar S4 INDY XC
YES! Polaris finally responded to our demands and is definitely back in the four-stroke snowmobile business. The fuel-efficient, smooth-running, and comfortable ProStar S4 INDY XC can meet the needs and desires of a broad range of riders looking for a four-stroke sled.
When Polaris offered the S4 engine in an XC package, I had the highest of expectations of XC heritage. After many miles and various conditions, I think the S4’s original TITAN and Adventure formats are currently its more accurate market categories.
The ProStar S4 INDY XC doesn’t yet meet XC-levels of performance expectations. However, it is uniquely relevant and well suited to easy cruising, distance touring, adventure, and utility styles of snowmobile experiences. It should also be noted that Polaris’ return to the four-stroke market is still new. Continued calibrations and fine-tuning are sure to follow.
Without any doubt, the capabilities of the ProStar S4 INDY XC are very well suited to the beginner, experienced cruiser, and seasoned touring categories of riders. If you are the right buyer, you can be prepared for a quality snowmobile that can check all your boxes. If you are the wrong buyer, beware of unrealistic expectations.
In the closing month of my 2024 season, I returned to the 2023 650 Switchback SP and, once again, found it to be extremely well suited to my particular desires for performance and agility. For those who place a greater emphasis on more aggressive agility and flickability in their snowmobile experience, the 650 Switchback really shines. I invite you to revisit my season recap article of this 2023 Polaris by clicking here.
As always, I thank Polaris and the Laquerre’s Powersports family for the opportunity to report on their products. They continue to understand, welcome, and support the unique connection we have with our readers and the expectations of real-world evaluation and reporting.
You can already read my 2025 long-term trial announcement! I look forward to all that the coming winter will bring to all of us. Your continued reads are recognized, respected, and appreciated. Ride safe, ride right!
Header photo : My Polaris 2024 ProStar S4 INDY XC
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