ROPS Ratings

[Harv]

We established in previous threads that each ROPS is designed and rated for a particular tractor. Besides the obvious mounting differences, the main factor was the weight of the tractor. The question now comes to mind -- how much does a tractor weigh?

Suppose I buy a shiny new 'Bota, just the basic tractor and its corresponding ROPS. But by the time I roll it sideways down that inevitable just-waiting-for-a-new-tractor-owner hill, I'm carrying 500 pounds of wheel weights, liquid-filled tires, an 800 pound boxscraper and a 52-ounce coffee cup -- full!

This is close to a ton of extra weight. Will the ROPS be happy about that? I assume there is good safety margin designed in, but how much? Do the owner's manuals say anything about this?

The idle mind strikes again...

 

[EddieW]

Harv, good question! I would've thought about that about the ttime my tractor was about half over on your new-tractor-owner hill. Most tractors have published weights, i.e., JD4300 - 2900#, B2910 - 1600#, NH TC33D - 2500#. That does not include any ballast or implements. My JD4300 with FEL - 800#, ballast in rear tires 200# per tire, box blade - 880#, plus me - 250# would weigh 5230# if it were to roll. Chances are if a tractor rolled there would be at least two points of contact that the weight would rest on but it is possible that all the weight could rest on a single point for an instant during a rollover. By the way, I'm not a computer geek but all the people I work with are! /w3tcompact/icons/smile.gif I'm still in denial!

 

[Harv]

<font color=blue>By the way, I'm not a computer geek but all the people I work with are! </font color=blue>

Eddie -- You have my deepest sympathy. /w3tcompact/icons/crazy.gif

 

[Bird]

Harv, of course you're right about the ROPS having a weight rating. The manual for my B2710 says the weight of the tractor (with ROPS) is 1740 lbs. There has been some discussion as to whether or not that includes tires and wheels, fluids, etc. so I don't know exactly what mine weighs. However, there is also a data plate on the ROPS that says for gross machine weight 3713 lbs., so I reckon Kubota allowed a sufficient margin there./w3tcompact/icons/smile.gif

Bird

 

[Harv]

Aha!!!

A "gross weight" data plate on the ROPS itself! Now we're talking. Anybody out there with a similar data plate -- how does that grosss weight figure stack up against your actual tractor weight with ballast, implements, coffee cups, etc.?

 

[gerard]

While I have absoultely no objective scientific data to back up my opinion, just looking at ROPS systems I can't imagine any extra weight from implements/loaders/ etc having a potential capacity problem in a rollover situation. They just are too overbuilt. Also remember in a rollover the ROPS is only taking SOME of the weight, the other half of the tractor (probably your hood!) is going to take about half the weight. Box steel in a ROPS configuration is pretty strong stuff and unless your rolling over a 30 foot cliff I think it a pretty overengineered piece of equipment.

 

[Anonymous Poster]

The engineer in me strikes again. I suspect that if you look at the tractor weight, and add in the max accessory weight by adding tire ballast, the weight of the loader, and the heaviest 3PH implement the tractor is rated to take (these ratings and weights are all in the owner/operators manuals), you will find it's a bit less than the gross weight rating for the roll bar. If not, there are some engineers at kubota who should be fired. But I doubt anyone's getting fired - -this is engineering 101 when designing something.

Now the coffee mug does add a twist to the problem!

 

[Harv]

Peter -

The numbers that Bird came up with support your suspicions. The safety factor seems to be about 2 to 1, and you can bet they're being conservative on the ROPS data plate.

I sorta thought this had all been worked out, but I always feel better with a few facts and figures under my belt. I guess that's the engineer in me. /w3tcompact/icons/smile.gif

 

[Harv]

A final footnote --

I mentioned this discussion to a good friend of mine who thrives on math and physics problems and, after some fairly involved calculations, he told me that a drop of 2-1/2 feet onto firm soil would double the apparent weight of the tractor on the ROPS.

His advice -- "Keep your tractors off the furniture!"