When I have seen chain failures in the modern era it's on a sled with at least two seasons on it.
Again, sincere question, were those chain failures you saw the result of hard riding or worn out parts or poor maint?
If an owner has a sled that has multiple seasons on it... and they are in the category of rider that sees broken chains "often"... IMO... that rider should be changing out the chain/sprockets when they become worn... I believe the same is true for a belt.
If you are a "hucker" or Turbo Chute climber... or generally are hard on your equipment... maintain it.
For the belt drive conversions that house the lower sprocket inside the there is some more protection for the sprocket than the stocker... but the sprocket does hang out past the case... and the case is not as strong without the cover on it... just a thought.
I've said it above...I have seen chains fail... it does happen VERY rarely... and when it does... other stuff can break as well.
If the rare breakage of a chain is a particular riders reason for running a belt-drive.... and the Pro's outweigh the cons... I'd say, for that person that they should invest in a belt drive.
For others... If the proven robustness of chaindrives, the cost and flexibility in gearing is more of a factor... especially when we are talking about factory installed systems....
Though in my experience... and the thousands upon thousands of posts and treads here on this very forum that I've read... chain breakage has not been an issue.
When I asked the Polaris engineers about this in 2013 "Why are the ISOC Race sleds NOT using the belt drive too?" I was told by them that the belt drive was not a good fit for the harshness of that type of operation... even with a slipper clutch on the driveshaft to minimize shock to the drive train... the belt-drives still have not been used... ISOC racers also maintain their sleds well.
In the new AXYS-Mtn released sleds... the chaincase is retained in all their "Heavy Duty" applications (Assault, SKS, 3"-Lug-PRO) ... Not just because of the gearing choices.
Installing a factory tensioner option on those sleds, if they went with a belt-drive in them, would have given them a more cost effective, and faster way to be able to run different ratios...and shave those ever important grams for bragging rights.... but they chose to design and tool up for the chaincase for real-world consumer/racer/corporate reasons.
In my view, the chaindrive AXYS-mtn sleds cost more to produce than the same model with a QuickDrive™. Polaris had to go to big expense to tool up for the AXYS-mtn chaindrive.
There are no shared parts... the cases/covers were not carryovers from flatlander AXYS sleds nor previous years. If the belt-drive could have been made as robust with the simple integration of a tensioner when they were starting from scratch... they would have done it, and it would have been easy to do. Polaris chose not to do this.
So far, for me... until more evidence is presented... the reason for running a belt-drive is lighter weight alone... and every benefit has a cost.
How much weight is that weight difference? I'd like to know....
How much actual inertial or Gyro force difference, for these actual applications, does that induce into the sled and is that perceivable?
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