'13 RMK, 150 miles, 2 shreded belts :/ ??

[paulharris]

With a hex shaft you will be using combo drivers driving through the track windows therefore the load is closer to the ends of the driveshaft near the bearings. flex is a non-issue with this setup. Hex shafts have been used for YEARS by all the manufacturers with few issues and proven to handle big HP (except the really old polaris 1" shafts). I don't think the pro is putting down that much power to bend a good quality 1 1/8" hex driveshaft. the biggest advantage is that it will run true for the belt drive.

 

[AK IQ Pilot]

With a hex shaft you will be using combo drivers driving through the track windows therefore the load is closer to the ends of the driveshaft near the bearings. flex is a non-issue with this setup. Hex shafts have been used for YEARS by all the manufacturers with few issues and proven to handle big HP (except the really old polaris 1" shafts). I don't think the pro is putting down that much power to bend a good quality 1 1/8" hex driveshaft. the biggest advantage is that it will run true for the belt drive.

I will guarantee you that if you tried to use a standard 1 1/8" hex shaft without the 205 self aligning bearing you will blow out the lower bearing in the quick drive bracket assembly.

There is a reason Polaris has used a belleville spring washer on the bottom sprocket bolt for over 2 decades. The hex shaft flexes and the spring washer allows the bottom sprocket to move back and forth on the shaft splines. This spring washer isn't there because of massive power, it's there because the hex drive shaft flexes especially when the rear suspension travels past 3/4 of full stroke.

There is no way a standard hex shaft will have less run out than the hollow shaft during the full stroke of the rear suspension. The tighter you run the track the more pronounced this run out will be.

IMO the problem is with the design/manufacturing of the belt. Polaris gave us a plain old Gates Poly Chain. When you look at the failure troubleshooting chart the #1 reason for teeth shear is because of excessive shock loads. If you are spinning your track hard in powder and suddenly hook up on some solid base layer you are ripping teeth from this Poly Chain. It's almost guaranteed.

 

[metallicat]

I will guarantee you that if you tried to use a standard 1 1/8" hex shaft without the 205 self aligning bearing you will blow out the lower bearing in the quick drive bracket assembly.

There is a reason Polaris has used a belleville spring washer on the bottom sprocket bolt for over 2 decades. The hex shaft flexes and the spring washer allows the bottom sprocket to move back and forth on the shaft splines. This spring washer isn't there because of massive power, it's there because the hex drive shaft flexes especially when the rear suspension travels past 3/4 of full stroke.

There is no way a standard hex shaft will have less run out than the hollow shaft during the full stroke of the rear suspension. The tighter you run the track the more pronounced this run out will be.

IMO the problem is with the design/manufacturing of the belt. Polaris gave us a plain old Gates Poly Chain. When you look at the failure troubleshooting chart the #1 reason for teeth shear is because of excessive shock loads. If you are spinning your track hard in powder and suddenly hook up on some solid base layer you are ripping teeth from this Poly Chain. It's almost guaranteed.

AK, I know very little about these new belts. It seems you may have some insightful knowledge.... When you say "a plain old Gates Poly Chain", what do you mean by that and what are the "new" ones? What is the better materials out there we are not getting? Just trying to learn..... There is something about this belt that doesn't feel "right"......

On a side note, snowracrer21, didn't mean to jump on you with the new thread. just getting frustrated trying to figure this out and sitting here wondering if mine is next. it's like a broken record with these damn belts!

 

[AK IQ Pilot]

AK, I know very little about these new belts. It seems you may have some insightful knowledge.... When you say "a plain old Gates Poly Chain", what do you mean by that and what are the "new" ones? What is the better materials out there we are not getting? Just trying to learn..... There is something about this belt that doesn't feel "right"......

On a side note, snowracrer21, didn't mean to jump on you with the new thread. just getting frustrated trying to figure this out and sitting here wondering if mine is next. it's like a broken record with these damn belts!

The Gates Power Grip GT2 is a kevlar reinforced belt. It's about 40% more expensive than a standard polychain with fiberglass cords. Most high HP blower applications use the GT2 belt. The CMX drive belt is Kevlar reinforced. They don't call it a GT2 belt but they say it's molded with kevlar cords and made specially for them by Gates.

This Polaris belt is designed on an 11mm tooth spacing. Typical tooth spacing for a Gates drive belt is 8mm or 14mm. 13.9 and 14mm belts are basically interchangeable. Gates does not offer an 11mm belt with Kevlar cords.....yet. Other tooth spacings are available from Gates but 11mm isn't at this time.

IMO heat isn't the issue either, at least not the main issue. Excessive heat is not mentioned as a failure mechanism for tooth shear. I've felt the belt several times. The front (coast) and back (load) sides of the belt are basically warm, maybe 100f. The top sprocket is hot +140f. The bottom sprocket is warm, maybe 90f at most. The point is the belt itself is just warm and it's basically the same temperature whether it's the coast side close to the muffler or the load side that is headed up to the hot top sprocket transferring the load from the jackshaft to the drive axle.

Our belts are failing due to tooth shear. When you look at the Gates Trouble shooting guide the one failure mechanism that sticks out is excessive load. The corrective action for mitigating tooth shear is to redesign the drive for increased capacity. You do that by a numbers of ways but short of completely redesigning the QD system a Kevlar reinforced belt may offer a stronger alternative for tooth shear.

 

[AK IQ Pilot]

I'd like to clarify something I posted earlier. The Polaris belts look like a typical Gates Poly Chain belt. They could be manufactured for Polaris by someone else and not Gates. It's possible that the Polaris belt is Kevlar reinforced.

If they are kevlar reinforced then we are back to a design/manufacturing issue. The belts aren't ripping in two they are shearing teeth. A kevlar corded belt would be less prone to ripping apart but not necessarily less prone to tooth shear.

 

[snowmobiler]

polychain even sounds cheezy.like a vacume cleaner belt.

 

[paulharris]

I will guarantee you that if you tried to use a standard 1 1/8" hex shaft without the 205 self aligning bearing you will blow out the lower bearing in the quick drive bracket assembly.

There is a reason Polaris has used a belleville spring washer on the bottom sprocket bolt for over 2 decades. The hex shaft flexes and the spring washer allows the bottom sprocket to move back and forth on the shaft splines. This spring washer isn't there because of massive power, it's there because the hex drive shaft flexes especially when the rear suspension travels past 3/4 of full stroke.

There is no way a standard hex shaft will have less run out than the hollow shaft during the full stroke of the rear suspension. The tighter you run the track the more pronounced this run out will be.

IMO the problem is with the design/manufacturing of the belt. Polaris gave us a plain old Gates Poly Chain. When you look at the failure troubleshooting chart the #1 reason for teeth shear is because of excessive shock loads. If you are spinning your track hard in powder and suddenly hook up on some solid base layer you are ripping teeth from this Poly Chain. It's almost guaranteed.

2 points you are missing: combo drivers are not mounted in the center of the driveshaft like the factory polaris ones, they are on the outer edges thus eliminating the flex you are speaking of, look at pic below. AND, the hollow driveshafts are NOT TRUE from the factory. regardless of flex, these driveshafts are not straight right out of the box. The splined ends are not attached perfectly square in relation to the shaft, thus creating a wobble. this obviously magnifies to excessive runout on the pulley. i have checked several of them...the steel splined ones and the new aluminum ones. the welded ones warp/move during welding and the glued ones may not be perfect from manufacturing or the end begins to separate while riding.

Again, hex shafts have been used for many years by all the manufacturers and they are not "blowing out" bearings like you speak of. And if you really think it will be a problem put the self aligning bearing in for peace of mind.

 

[snowracer21]

Polaris warrantied the 2nd belt... luckily, otherwise I would have told them to keep the sled.

dealer told me, i'm the ONLY customer to have this problem... and Polaris claims there's been very few problems with the drive belts...

LOL. sounds like denial

 

[Leaf27]

guys keep wondering why there are so many problems but the answer is very clear. These sloppy tolerances are not compatible with a non tensioned belt drive....Period.

the only real fix is to install billett pulleys and a perfectly true driveshaft. (a standard hex driveshaft)

Agree 100%, no room for error of any amount without a tensionor.

2014 Pro comes with tensionor watch and see.

 

[prointhesnow]

QD belts

My first belt lasted 110 miles and it has me really worried. I have been riding Polaris for 35 plus years and I have had many up and downs and struggles with there product line but I'm to proud and stubborn to change. I ride sled as hard as anyone and thats what I buy them for. My dealer thinks I got some ice in the belt and thats why it happened. I said what about all the testing Polaris did on the QD? They said they threw rocks, gravel and ice and had not problems.

 

[Boston Racing]

Is there any chance that 163" sleds are the ones having trouble and not the 155's? Just curious is all...I cannot for the life of me figure out why some of these are having issues and others are not!!

Ours are 163's and you know how we baby them

 

[geo]

I'm at about 750 miles and I think the belt is broken in now. It has developed about a 1/4" of free play cold (tightens up when warm) and has started to walk along the sprockets centering itself where it wants. It also will roll away if I stop on a packed trail.

I have also started to lose nickle plating on the lower sprocket (looks like bubbles).