SOME THOUGHTS ON QuickDrive® BELT ISSUES

[mountainhorse]

I was told carbon back March by Polaris engineers... but I have no confirmation of weather it is a Gates Carbon etc...

I can tell you that it is a custom belt. The tooth pitch is 11mm compared to 8mm on the typical toothed belts.

No aftermarket belts that I know of to put on there... at least yet. It would be nice for someone like the SPi group to contract for affordable Gates replacement belts to be made.

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I realize that it has no tensioner, that wasn't the question.

Is it a carbon or standard GT2 belt was the question.

Tension was much less important with s carbon belt in my experiences.

 

[wyofreeride]

Thanks for the info.

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[mountainhorse]

Bump...


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[winter brew]

Pulley runout. Im not seeing or hearin much about this is all these belt failure threads. Trueness of pulleys IS the belt tensioner. Pulley runout off by even a small amount is going to have a huge effect on belt tension as it rotates.
Perhaps C3 or someone with a lot of belt drive experience can shed some light on how critical it would to have a belt going through constant loose/tight while under a load. According to Gates, improper tension OR excessive runout will cause tooth shearing. I just dont see a mystery here considering the ends of the shaft are misaligned and failing and a cast pulley which may or may not be very true.
Any belt failures on those running steel shafts?

 

[rp2000r]

13 Pro, Steel shaft since day 1, 200 miles, No issues yet....

 

[mountainhorse]

Any belt failures on those running steel shafts?

Yes.

 

[Hazard]

Pulley runout. Im not seeing or hearin much about this is all these belt failure threads. Trueness of pulleys IS the belt tensioner. Pulley runout off by even a small amount is going to have a huge effect on belt tension as it rotates.
Perhaps C3 or someone with a lot of belt drive experience can shed some light on how critical it would to have a belt going through constant loose/tight while under a load. According to Gates, improper tension OR excessive runout will cause tooth shearing. I just dont see a mystery here considering the ends of the shaft are misaligned and failing and a cast pulley which may or may not be very true.
Any belt failures on those running steel shafts?

Agree, and add snow in the pulleys with not correct tension, cogs are not completely in pulley, that would rip cogs off.

 

[mountainhorse]

Here is what I'd like to see in 2014 for my respected friends in Roseau... sincerely.

Vented lower sprockets in different ratios, similar in design to these.

Tensioner, this will allow changing ratios.... and the system will be able to tollerate unavoidable production variance. Plus allow setting ideal pre-load on the belt.


Urethane top sprocket Will make the belt/upper-sprocket a more shock resistant unit that can absorb any minor twisting in the drive train.
These sprockets also will be kinder on the belts when there is run-out in the system.

Run the same driveshaft extrusion with a drive-stub that extends further into the shaft...more durable and will remain true longer.





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[Z-Man]

Take a look at the CMX belt drives. They have a tensioner and the brake is on the bottom shaft. They have a kit that fits all the pros and the assaults.

 

[LoudHandle]

Pulley runout. Im not seeing or hearin much about this is all these belt failure threads. Trueness of pulleys IS the belt tensioner. Pulley runout off by even a small amount is going to have a huge effect on belt tension as it rotates.
Perhaps C3 or someone with a lot of belt drive experience can shed some light on how critical it would to have a belt going through constant loose/tight while under a load. According to Gates, improper tension OR excessive runout will cause tooth shearing. I just dont see a mystery here considering the ends of the shaft are misaligned and failing and a cast pulley which may or may not be very true.
Any belt failures on those running steel shafts?

Regardless of tensioner or no tensioner, if you have runout you will have issues. A tensioner only takes up manufacturing tolerances (center to center or slight variations in belt length), NOT badly manufactured out of round or off center sprockets.

I keep hearing people talk about a tensioner being the cure all for this belt drive, it is not! If the sprockets are out of round or broached off center you still have a cyclic tensioning situation and no tensioner is going to solve that issue. The only way to fix that is to have true (zero run out, concentric) sprockets. Also likely need a quality belt if Polaris did go a cheaper Kevlar / rubber belt, It should be the poly-ureathane / Carbon Fiber reinforced one.

 

[Z-Man]

Regardless of tensioner or no tensioner, if you have runout you will have issues. A tensioner only takes up manufacturing tolerances (center to center or slight variations in belt length), NOT badly manufactured out of round or off center sprockets.

I keep hearing people talk about a tensioner being the cure all for this belt drive, it is not! If the sprockets are out of round or broached off center you still have a cyclic tensioning situation and no tensioner is going to solve that issue. The only way to fix that is to have true (zero run out, concentric) sprockets. Also likely need a quality belt if Polaris did go a cheaper Kevlar / rubber belt, It should be the poly-ureathane / Carbon Fiber reinforced one.

Even if everything is perfect, the brake should not have been on the top shaft exerting forces on the belt in the opposite direction of the normal force on the belt cogs. It's a bad design and I predicted problems when I saw it at the sneak preview.

http://www.crazymtn.com/sifiso/pages/cmxds.html

 

[LoudHandle]

Even if everything is perfect, the brake should not have been on the top shaft exerting forces on the belt in the opposite direction of the normal force on the belt cogs. It's a bad design and I predicted problems when I saw it at the sneak preview.

http://www.crazymtn.com/sifiso/pages/cmxds.html

While it is my opinion that brake drag is causing an excess heat soaking of the top sprocket, with the cheap single piston sliding caliper design. I don't think they would be having the current issues with a dual piston caliper design that pulls the pads away from the disc. As the top sprocket is running nearly twice the temp of the belt and bottom sprocket. Even if the disc was on the bottom, like the CMX, unless they solved the brake drag issue it is still prone to fail the belt. If they splined both ends of the drive shaft and divorced the brake to the PTO side under the driven clutch, then the sh_tty stock brakes would no longer be an issue.

On the other hand the C3 conversions seems to be working fine and surviving under the same conditions. From the reports I've read.

 

[metallicat]

Even if everything is perfect, the brake should not have been on the top shaft exerting forces on the belt in the opposite direction of the normal force on the belt cogs. It's a bad design and I predicted problems when I saw it at the sneak preview.

Even if the brake was on the bottom, when applying the brake, wouldn't it still exert forces on the belt in the opposite direction of normal force? That is what the brake is meant to do....Stop the "normal" direction of the track. why would it make a difference what shaft it's on. (besides the ongoing debate of not having brakes if the belt brakes...) Or am i not thinking correctly on this? I guess it would have more cog/sprocket surface contact to spread the load out when braking?.?.

 

[builder801]

forces on belt

Even if everything is perfect, the brake should not have been on the top shaft exerting forces on the belt in the opposite direction of the normal force on the belt cogs. It's a bad design and I predicted problems when I saw it at the sneak preview.

Even if the brake was on the bottom, when applying the brake, wouldn't it still exert forces on the belt in the opposite direction of normal force? That is what the brake is meant to do....Stop the "normal" direction of the track. why would it make a difference what shaft it's on. (besides the ongoing debate of not having brakes if the belt brakes...) Or am i not thinking correctly on this? I guess it would have more cog/sprocket surface contact to spread the load out when braking?.?.

If the brake is on the top shaft when you apply the brake the QUICK DRIVE BELT is stopping the bottom shaft and track , so if you move the brake to the bottom shaft the brake is stopping the track not the quick drive belt ,witch takes the stopping power off the quick drive belt in theory , and then if the belt breaks or strips off cogs your brake is on the bottom shaft witch would stop the track !!!

 

[Z-Man]

If the brake is on the top shaft when you apply the brake the QUICK DRIVE BELT is stopping the bottom shaft and track , so if you move the brake to the bottom shaft the brake is stopping the track not the quick drive belt ,witch takes the stopping power off the quick drive belt in theory , and then if the belt breaks or strips off cogs your brake is on the bottom shaft witch would stop the track !!!

Exactly, If you brake on the lower shaft you are not exerting force in the opposite direction on the belt, the engine is still trying to turn it forward. When you break on the top it exerts all the force in the opposite direction through the belt. This causes an sudden extreme change in force to the cogs of that belt that it was never designed to handle.

 

[metallicat]

Yup. Gotcha. guess i just had to read it and think about it more! Duh.....

 

[Z-Man]

Think slamming your car in park at 60 mph and it trying to brake through the driveline.

 

[dragrace1933]

Polaris quickdrive junk

ive put a turbo on my sled and have striped a belt every ride, i put a tensioner on it and striped two so far, i want a chain case or pulleys to run a gates belt, any body have any ideas

 

[LoudHandle]

ive put a turbo on my sled and have striped a belt every ride, i put a tensioner on it and striped two so far, i want a chain case or pulleys to run a gates belt, any body have any ideas

C3 or Avid can set you up with billet hard anodized Sprockets (pulleys) and belts, although the belts are available thru any Gates power transmission distributor. My impression is Avid is a US distributor for the C3 belt drive for Polaris anyway. CMX is another choice although more money their kit comes with the whole drive train included (jackshaft, sprockets, brake, drive shaft, belt, mount plate, etc). Even going back to chain case with new parts is a steep proposition.

Let us know which way you go and how it works out for you.

 

[mountainhorse]

There are some Quickdrive owners that have problems and others that are not...

Runout of the pulleys... caused by shaft "wobble" or pulley mfg error...

dragrace1933... can you check your runout with a dial indicator?



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