Caroni Flail Belt Failure

[IslandTractor]

This link provides information on causes of belt heat, belt life, effects of ambient temperature changes and a bunch of other stuff relating to this thread. .....
MRO Today - Think you know drive belts?

Bill in NC

So, from the article by the Gates product manager:

" Ambient temperature, time of exposure, ventilation and drive design affect internal belt temperature. Tests indicate V-belt service life is cut in half for every 36-degree increase in ambient temperature. And, for every 2-degree increase in ambient temperature, there is a 1-degree increase in the belt's internal running temperature. Thus, each 18-degree increase in internal belt temperature cuts belt life in half. "

If the earlier post on 20,000 expected hours of operation is correct, and we assume a conservative 100 degree "normal" temperature for the belt (close to midpoint in operating range) that means each 18 degree increase in internal belt temperature from operation will reduce operational life expectancy by half. 118 degrees equals 10,000hrs, 136 degrees = 5000hrs, 154 degrees = 2500hrs, 172 degrees=1250hrs, 190 degrees = 625hrs. etc.

I imagine that the belt housing temp would be lower but still in the ball park of internal belt temp after an hour or two of mowing time. If I can keep my hand on the cover for at least a couple of seconds I'd imagine the temp is less than 154 or certainly less than 172. If these assumptions are correct then we should be getting a minimum of a few hundred mowing hours, probably double that, from each set of belts. That would add up to at least several seasons of mowing for an average non professional user I'd guess.

All this is only quasi realistic given the various assumptions but it certainly makes you think that Sunspot's early belt failure at 10 hours or so must have been due to something other than belt temp.

Unless these calculations are way off, it also makes me reconsider how the debris I found inside my belt cover could possibly be belt related.

 

[Eagleview]

Don't forget it's the actual belt and pully temp that is what counts , not the cover that is acting as a heat sink and dissapating heat . i bet if you spat on the pullies it would sizzle .

 

[sunspot]

IT, that stuff in your picture looks more like ground up thatch than rubber.

Bill, thanks for that link. It's a good read. The Caroni belt cover has vent slits all around the sides of it. An impeller under the cover would help to move more air.

The main point of this thread was early belt failure and it looks like I am not the only one having this problem.
I received my new belts yesterday and they are the size posted in this thread.
B43 21/32" x 46". It does not have any metric size on the belt or the package. I'll post a picture tonight.

 

[IslandTractor]

IT, that stuff in your picture looks more like ground up thatch than rubber.

Bill, thanks for that link. It's a good read. The Caroni belt cover has vent slits all around the sides of it. An impeller under the cover would help to move more air.

The main point of this thread was early belt failure and it looks like I am not the only one having this problem.
I received my new belts yesterday and they are the size posted in this thread.
B43 21/32" x 46". It does not have any metric size on the belt or the package. I'll post a picture tonight.

That belt size is the same as 17mm x 1090mm internal.

I hope the debris in the belt cover is thatch. The color and consistency threw me off but I agree that with that much material it would have to be shredding the belts and there was no evidence of shredding, just heat.

 

[wstr75]

It could be there are several factors causing the problem. 1) The belts themselves may be from a problem batch with some sort of processing, material composition, etc. difference. 2) The belt tensioning may be off a bit either too much tension or not enough tension. 3) The housing may not be wicking-off the heat fast enough from the pulleys and belts. 4) Item or activity #4. 5) Item or activity #5, etc., etc., etc.

If it happens again with the new belts, take note of the ambient temperatures, the type of cutting (brush, wet grass, tall dry fescue, etc.), how long the mower was operated between breaks (one hour continuous operation, 15 minutes at time with 5 minute breaks, etc.) and how fast the PTO was turning.

My guess is there was something a bit out of whack with those original belts leading to premature failure that was also influenced by ambient temperatures, belt tensioning, housing heat sink characteristics and PTO speed. In other words, the belt quality was not up to 25,000 hours at perfect conditions and may have been 5,000 hour belts that gave up after a few hours because of the other factors all teaming-up together sort of like how we buy tires with speed, wear, dry and wet operation ratings. I'm willing to bet there are similar relevant ratings on belts, too. If Caroni is like the car manufacturers, it is putting OEM belts on that may not be as highly rated as what can be bought in the aftermarket. The operative words are "can be bought". Does anyone know if there are belt ratings and places on the Internet where highly rated V-belts can be found and purchased?
Bill in NC

 

[TNhobbyfarmer]

Is it me or does it seem that flail mowers are quite fussy with respect to use and maintenance? I was ready to purchase a Caroni, but now I'm having second thoughts. Bear in mind that I am forming my opinions only from TBN threads, not actual ownership. I try to maintain my equipment well, but it seems that flails are over the top as far as maintenance is concerned. I want something that I can use regularly without constant fears about grease, belts, hot belt covers, etc, etc., etc.

 

[IslandTractor]

Is it me or does it seem that flail mowers are quite fussy with respect to use and maintenance? I was ready to purchase a Caroni, but now I'm having second thoughts. Bear in mind that I am forming my opinions only from TBN threads, not actual ownership. I try to maintain my equipment well, but it seems that flails are over the top as far as maintenance is concerned. I want something that I can use regularly without constant fears about grease, belts, hot belt covers, etc, etc., etc.

This thread may be giving the wrong impression. Many of us are first time flail owners and are just using this thread to understand the vagaries of belt maintenance and trying to figure out what exactly is normal operating behavior.

I think flails are certainly more fussy than your basic rotary bush hog (what isn't) but probably not a lot different from a finish mower or tiller or other farm implement with more than a couple of moving parts. To my knowledge, we have had one or two reports of belts breaking on the forum recently. We have been exploring what might have caused that and I have been tinkering with my mower to figure out the best belt tension but throughout the mower has worked fine the whole time I've had it. I am still not quite sure if this belt heat issue is truly a problem or not. I suspect people with finish mowers and tillers have belt issues on occasion as well.

With regard to maintenance, again I'd say they require more maintenance than a bush hog but less than an FEL or BH. Basically just check the gear box oil and grease three points before use. Takes all of two minutes tops. I certainly would expect to spend more time maintaining the FEL and BH per hour of work just given the larger number of grease zerks. There would occasionally (once every couple of years?) be a need to reverse or eventually replace the flails themselves. That would certainly be a good afternoons work and cost $100-200 for replacement parts.

If you only need to do rough bush hogging and see no advantage to smaller storage space or overhang or need a finer cut then the bush hog is tried true and almost idiot proof. A similar grade bush hog is a little cheaper than the equivalent grade flail IMO. If all you want is to mow lawns then a finish mower is also obviously a more common option although they are more expensive and I would think require about as much maintenance (belts and blades). The niche for the flail is probably at the intersection of the bush hog and rotary with considerable overlap of each performancewise and for some this allows us to buy and maintain a single cutter rather than two.

 

[sunspot]

Here are a couple of pictures of the replacement belts. They are made in......wait for it.......India

 

[IslandTractor]

Here are a couple of pictures of the replacement belts. They are made in......wait for it.......India

I presume the Gates equivalent B43 belts are US made. At $7.35 each they are hardly a big ticket item.

 

[Reg]

I have stalled the tractor occasionally while mowing with the flail. I don't believe I've ever heard belt squeal. However, there was quite a lot of what I think may be belt debris (fine fluffy stuff that did not appear to be vegetal in origin) at the bottom of the belt cover when I took it off this weekend. That was only about 5 mowing hours since I last took the cover off. Just for reference what I mean by quite a lot is enough to half fill a spray paint can cap...it is light and fluffy so it weighs next to nothing. Again, I did not do any careful inspection but it seemed suspicious to me that it was almost all grey brown in color and that I'd only been mowing green grass the day before. See photos. I'd love it if someone told me it was just fine mowing crap and not belt related.

I think I will first try to max out the existing spring adjustment. Then I will try a solid replacement for the spring but will be careful not to over tension it. I did get a infrared thermometer (thanks Amazon) so I should be able to tell if there are any changes in belt cover temperature. I just read IronHorse's new suggestion regarding strength of the spring replacement. I'd already picked up some 1/8 inch smooth steel rod that I intend to cut and bend some v hooks onto the ends to serve as a spring replacment. I may or may not get around to doing the switch this weekend but will report back. I could not find a more powerful spring in appropriate size at HD and don't know if I'll have time to track one down before the weekend but that is the other route to consider.

If you have NEVER heard squealing and HAVE stalled the tractor without burning the belts.... Doesn't that kinda indicate that the belts are gripping the pulleys "plenty well enough" ?

Until I do at least ONE measurement of the force required to push that roller back and compare it to some recommendation from (non microsoft) Gates I don't have an opinion as to whether or not there is too little or too much tension on the belts - other than the lack of squeal and ability to stall both your tractor and mine without smokin' 'em. I havn't yet found minimum diameter pulley recommendations for those belts either, another possible factor, but there are limits to how much I'm willing to re-engineer this thing.
Not that I know yet whether it NEEDS any re-design or not.
If the tension is right or about right my next step would probably be to try the equivalent notched belts, subject to them not needing other significant changes.

I'm too busy with other things the rest of this week and I want the replacement belts in hand before I take that cover off again anyway, so it may be a while before I have anything to type.