Strange belt failure

   / Strange belt failure #1  

dnw64

Veteran Member
Joined
Feb 13, 2017
Messages
1,724
Location
SE Vermont, South Jersey
Tractor
Kubota B3030 Cab
Never seen this before. It's on my Caroni flail mower which I've had almost 2 years.

Before heading out on my first pass of the year I greased all the bearings, and while greasing the main bearing at the end where the belts are I saw what looking like a piece of belt sticking through one of the ventilation louvers.

So I took the cover off and two of the belts were shredded. OK, not great, but whatever. It has probably 20-30 hours on it (don't really know) and maybe the factory belts were junk. And maybe that still is the main problem, but what I saw upon further inspection is that chunks of the inner part of the belt were still stuck in the sheave. Like, really stuck. Couldn't get them out with my fingers - had to use pliers. The only explanation I have come up with is that they got hot enough that, when stopped they melted to the sheave and at the next use pieces got ripped out.

Any other thoughts/suggestions?
 

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   / Strange belt failure #2  
Had the same issue with my Flail mower last week, Chinese crap belts were less then 3 hours old and just basically melted. I had to use a wire knot brush on the angle grinder to clean the cooked remains out of the pulley. Took the belt down to my local NAPA and they set me up with a set of Kevlar reinforced belts. After a few hours of mowing I pulled the cover to re-tension and they no sign of abuse at all.
 
   / Strange belt failure #3  
When I pulled the cover off my Caroni, had something quite similar. The belts were destroyed and there were chunks, just like your picture, on 2 of the three pulleys
 
   / Strange belt failure
  • Thread Starter
#4  
OK I'll hope the new ones I put on hold up better.
Thanks
 
   / Strange belt failure #5  
Loose belts create heat. Whenever you have multiple belts on the same pulley it is imperative that you get matched belts. A good belt shop will be able to get you belts from the same exact mold and stretch them to the exact length if there is any variation.
 
   / Strange belt failure #6  
Wrong size belts or cheap belts. The belt(s) should NOT drop below the top of the pulley. They should also NOT touch the bottom of the pulley. This typically occurs when a mix of inch and metric sizes are used--Belts and pulleys. Usually from import products.
 
   / Strange belt failure
  • Thread Starter
#7  
I run a mid-size wood shop. 12 employees, $1mm+ in equipment. We used to ask for matched belts on our multi-belt equipment. Our supplier told us 15+ years ago that it is no longer a necessity, that all B43 belts are the same, etc.

HOWEVER, it was very clear, after installing the three new belts, that one was looser than the other. No idea as to the original ones. Never checked them, assuming the mfr knew what they were doing...
 
   / Strange belt failure #8  
Did you check for straightness across both pulleys?
It could be a old bet got rusted in the pully and it's all over at that point.

I have had decent luck with chinese kevlar belts but I dont run 3 on the same pulleys.
 
   / Strange belt failure
  • Thread Starter
#9  
I didn't check for parallel on the sheaves. Will do that next time I check the belts.

Could have rusted, but it's not like it was sitting for years - just last fall to this spring - and I keep it under cover, so any moisture was just from environmental humidity.
 
   / Strange belt failure #10  
Well, I guess I'm going to check my Caroni belts before next mow. I'll do that after I cuss the designer who put the roller grease zerks right behind the skids. I got to figure out how to grease the roller without unbolting the skids.
 
   / Strange belt failure #11  
Ya, you still need matched belts. And I agree with TinHack that the belts being at the bottom of the pulley grooves is wrong. OEM cheaped out on the belts for sure.
 
   / Strange belt failure #12  
Belts riding in the bottom of those grooves are either worn out or are A-belts used where B-belts should be.
 
   / Strange belt failure
  • Thread Starter
#13  
Well, I guess I'm going to check my Caroni belts before next mow. I'll do that after I cuss the designer who put the roller grease zerks right behind the skids. I got to figure out how to grease the roller without unbolting the skids.
My roller zerks are accessible - maybe we have our skids and rollers at different positions.

What I don't understand is why one of the zerks is inside the belt cover and you can't get at it without taking the cover off. If I hand't checked my belts I wouldn't have realized it was even there.
 
   / Strange belt failure #14  
I can grease my Betstco/FHM through the guard but always remove it to check belts when I do. btw, one reason I chose more narrow than my CUTs can handle besides maneuverability is to have 2 belts instead of three. OEMs are B-size 59 1/2" but I can use 59" or 60" off the shelf from TSC.
 
   / Strange belt failure #15  
My roller zerks are accessible - maybe we have our skids and rollers at different positions.

What I don't understand is why one of the zerks is inside the belt cover and you can't get at it without taking the cover off. If I hand't checked my belts I wouldn't have realized it was even there.
Well, I guess i need to look for another zerk too. I don't recall which height I have my skids set too. As I received it, it was fine. I think I raised the shoes. But, it should work regardless and it doesn't.
 
   / Strange belt failure #16  
I did with my flail mower what I did with my 5' KK tiller, all but removed the gauge skids and after decades of grading with box blade, angle-blade, and landscape rake have learned to use wrist vs arm adjustments on the position control so work to the height or depth desired. IMO if you don't see grease oozing out to be wiped off you're not over-doing that part of PM.

(you guys knew that :))
 
   / Strange belt failure #17  
I have seen that on multiple belt systems and agree, the whole matched belts no longer needed myth is hog wash. I have been using Timken industrial belts for the sole reason they are manufactured in the USA and they have fit better than any thing else I have tried.

I think that the belts were hot from slipping and once shut down they stuck to the pulleys.

I noticed that the Gates belts that I purchased prior to the Timken didn't feel as tacky. They were also not as pliable, very stiff and the pulleys felt hotter after a few minutes of usage, there was a definite decrease in temperature using the Timken for the same amount of time. I have slowly ordered Timken belts for everything and keep spares for any emergency that arises. No one local stocks them so I order them from Motion Industries.
 

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