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Discussion Starter #1
Ok so we all know that ariens makes it really difficult to match a after market belt to their blowers as you cannot find any specs for length width etc. My blower is a 921037 and the drive belt is a 07200717 this is the new # for the old 07200522. This belt according to ariens manual is supposed to be a 3L wrapped belt not a raw edge, but what they are selling is a raw edge belt. So I started looking for a wrapped belt .375 or 3/8 but could not find a cross that matched to the oem number. With the constant idler tension I can see that it should indeed have a wrapped belt not a raw edge. So upon further inspection I noticed that the traction drive sheave with the belt still on the machine was riding at the very bottom of the sheave (pulley) and when I measured the width of the pulley it is for a 1/2" belt and matches identical to the width of the auger drive pulley width that is a 17/32. The sheave on the crank for the traction drive is .375 wide or 3/8. So now I know why my belt is wearing at the bottom and taking chunks out of it. So has anyone else noticed this difference, I contacted the dealer and basically got an oh well! I tried to find out if any other Ariens with the AX motor had a top sheave that ran a 1/2" traction drive belt so that I could match both sheave widths of course he said he wouldnt know that. So has anyone noticed this and actually made the sheave change, if so what did you use.
 

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Discussion Starter #3
Hello sir of which are you referring to the Belt , the top sheave , or the bottom sheave. My oem belt is a 3/8 the top sheave width is a 3/8 the bottom sheave however from factory is for a 1/2 belt and this is where I am getting the wear as 3/8 belt is bottoming out in the pulley. The next time you are under your belt cover look at the width of the the lower drive pulley and see if it matches the width of the auger pulleys. I am trying to find out if my machine has a wrong part in it or if this is an engineering flaw.
 

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both i have no wear on the belt
ive not looked at the bottom pulley
dont see ariens designing someting that does not work
and the bottom pulley part number is the same for most of if not all the 921 series its for sure the same as the 24 28 30 sho and 30 deluxe
 

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Discussion Starter #5
You are correct on how machines that use this set up. My point being that after 35 yrs. of working on everything with a motor I can say beyond any doubt that you can not effectively run a 3/8" belt in a pulley thats for a 1/2 belt. The V belt on any application when in the pulley that is sized correctly for that belt will be flush or almost flush with the top of the pulley, and this 3/8 belt is no wheres close to the top and is actually sitting better than 3/8 from the top, because its in a 1/2 pulley. I have had Ariens for over 30 yrs. so yes they make a good product but in this world any and all companies can and do make design flaws, So as you stated if there are all these blowers that have 2 different size (width) pulleys then could this as well be why the auto turn on these does not work as well as they thought it would. Mine would work with a brand new belt and soon start acting up.
 

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my auto turn works perfect best thing since sliced bread
my drive woks perfect
so does the whole machine
the 4 L pulley as i understand it can run 1/2 or 5/8 belts with the 1/2 running deeper in and is claimed better grip
Ive not measured the bottom pulley for the drive nobody else is having issues with that and pulley has been out for years
doughtfull ariens missed that being right
hardly fair to compare that to auto turn and a junky driveway( mines not a good driveway either still fine )
iam glad i have the orignal axle location much better down force on the bucket
I myself have 35 plus yrs working on things
 

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Discussion Starter #8
I am not out to debate if the machine is good or bad I wouldnt have bought it if I didnt believe it is a good machine. And yes there are several people that state that their auto turn is erratic and sometimes nonperforming on many other forums. I am glad that you have a perfect machine, mine however is not perfect that is how I came to discover the fact that it is running a 3/8 belt in a 1/2 pulley. I am simply asking people who can actually look at the lower traction drive pulley that has one of these models that use this set up and see if their belt is riding at the top of the pulley or the bottom, and if everyone starts saying its at the bottom then its a design flaw. If people start saying that theirs is at the top then my machine has the wrong sheave in it. Thats what I am looking for, actual verification of how the belt rides in the pulley on other machines. As I said my machine works but of the things that I have noticed in how it performs led me to look at things a little deeper. By the way I have changed this belt every season and never noticed it before as I was simply putting a belt on, it is not easy to see until you take a light and go look for it.
 

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just looked at mine
Bottom
drive never slips belt has no wear
no issue
If you dont think ariens tested that carry on
 

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Discussion Starter #10
Thanks for looking. My belt as well shows no wear on top or sides however the inside is where I am getting the most wear. the rest of the belt looks brand new. If you look at the lower pulley with a flashlight at the very inside of the pulley V , on mine I can see the 1/4 inch track where the belt inside is riding so that is telling me that the actual belt sides are not what is creating the torque transfer but only the belt land and I am not getting the power transfer the way that is should. In the flat of my driveway I do not notice any real difference however on the uphill portion that rises about 7 ft in 50 ft that is where I can tell the difference.
 

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Discussion Starter #11
The Ariens auto turn feature is a lot in aspect like a lawn tractor differential, and as we found out on a cub cadet tractor that had a bad pulley that when under load if the belt slipped a little bit the differential reacted to the slip causing the the unit to feel as if the rear end was going out,and trying to tranfer power to the other axle when it didnt need to, it was not the rear end but a wrong (bad ) pulley. Once the right pulley was installed and matching belt all became fine, not just with that unit but 6 others. The cub had the wrong belt for that pulley and was too riding on the land portion of the belt. This is why I question one of the pulleys (width size) on my ariens.
 

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I took a look at my belt. It is 3/8" wide by 1/4" deep and raw edge with the bottom surface being smooth and unmarked. According to my Ariens parts manual it is correct (07200717 v belt 3L section raw edge). The belt sits slightly above the sheave of the crank pulley and 1/8" below the top of the driven pulley (swing plate assembly). The groove in the driven pulley is 11/16" deep and the belt wear surfaces are clearly visible on this pulley but the bottom of the groove is rust coloured so no contact. It appears on my machine that the belt sits 1/16" from the bottom of the driven pulley which seems satisfactory from a user perspective.

My machine has a great deal of use since I do 8 driveways and usually do them a few times per snowfall to ensure easy access for my neighbours who are elderly and infirm in a few cases. I have already worn out one rubber tired driven disc but the belt is original and has lots of life yet.

I would have expected the two pulleys to have the same width, but it is not a problem in my case. It would be difficult to change the driven pulley since it is engineered into the swing pulley so it would be easier to change the engine crank pulley to a 1/2" wide unit and match the belt size. The down side is that the driven pulley would effectively increase in diameter and slow down the ground speed some. To compensate the engine pulley could be increased in diameter. Here is a link to a calculation that will help you with the gearing change: Pulley size and RPM in this the A pulley rpm would be your engine speed (usually about 3600 rpm) and the pulley A diameter would be diameter of engine pulley and pulley B would be the diameter of the driven pulley. So the calculated rpm would be that of the driven pulley. So measure the current pulley diameters and enter the engine pulley diameter but for the driven pulley diameter enter a 1/4" less than measurement for the first stock setup. For the 1/2" belt setup use the driven belt full diameter. You can then adjust the engine pulley diameter to match the rpm of the stock setup by trial and error. That will be good enough but to be perfectly accurate the running diameter of the belt is about 1/2 the depth of the belt or about 1/8" below top of sheeve.

Hope this helps.
 

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Discussion Starter #14
I just talked to a friend of mine that owns machine shop with several CNCs he is going to take my stock pulley an build a new pulley and calculate the new size with a cut for 1/2 belt including the factor of the 1/2 belt riding farther to the outside of the swing plate pulley. He to owns a deluxe 30 so is very interested in the project. He has also verified that his belt is running in the bottom, when he looked at his he said Whaaaattt!!!
 

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I suspect that Ariens may have done this deliberately, so that when the belt is slack (drive or augur not engaged) that it is less likely to jump off the pulleys. I would think that unless the belt is bottoming out in the pulley (and thus losing grip on it's sides) that "ride height" would not matter . . . For that matter, is there any chance they used a deeper than usual pulley for just this reason? Seems like a fix in search of a problem from here . . .
 

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Discussion Starter #16
As for the Belt itself everything that has been published for my unit (921-037) calls it a 3L wrapped belt. Even ariens site calls it out as a wrapped belt with no rubber bleed through and every online calls it a wrapped belt but it is not what they are selling as most are hooked it OEM supply for ariens belts. Again you cannot find a cross from anyone for this belt in a wrapped belt.
 

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Discussion Starter #17
I could see that in a clutching system however this belt never goes slack as it has a full time spring tensioner on the idler pulley and the spring is pretty stout
 

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The swing plate deflects when the drive clutch engages so the belt is no longer in alignment with the engine pulley. This has caused problems in some earlier applications. So tadawson's observation is a good reason for Ariens setup.
 

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Discussion Starter #19
Yes we looked at that and with the constant idler spring pressure the belt should not go slack but be absorbed by the tension spring this is what the 3/8 does right now. We are first going to put a 1/2 belt or 17/32 belt on it as there is plenty of room at the crank pulley and the belt guides. Yes it will ride a little higher in the top .375 pulley but it will be cheaper than doing a fab on a new pulley just to see what difference it makes.
 
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