Tractor Rollover

[WinterDeere]

But that would be on a static object once that object is in motion none of the collected data would apply.

A static tip point is all you're ever going to get, I think. Rotational velocity and moment will impact how far you might tip when rolling over an object at speed, but introduces too many variables to be of actual practical use to anyone. Besides, your cheap inclinometers are static instruments, only.

 

[dadohead]

A static tip point is all you're ever going to get, I think.

Yes, static stability test is all you get. Mowers follow ANSI B71.1 stability test on a tilt table: 30° longitudinal, 20° lateral. There are no mandatory tests for tractor. Manufacturers do internal testing and will provide guidelines with best practices... too many variables. It remains YOUR responsibility to stay safe.

 

[MossRoad]

The manual on my Kubota L5030, in the safe operation section only says to set the wheels as wide as they go for widest practical application ... Nothing about reduced weight capacity or increased wear ... The wheels have adjustable spacing, I have them at there widest.

My Massey Ferguson GC 1725 MB doesn't have adjustable wheels, and doesn't say anything about wheel spacers, I have 3" spacers on the back, and 1.3" on the front ... Haven't noticed any "wear" or problems in the 735+ hours I have on it, I bought it new ...

My "seat of the pants meter" went off at this point, my front tires wouldn't pull/steer up hill in 4X4 .. the 5' brush hog on the back is a bit heavy for it, and I had forgotten to put rocks in the bucket like I normally do for front ballast ...

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I gingerly got off the top side holding onto the ROPS hoping it wouldn't tip over, it didn't ... I gave it a little "shake" ... Rock solid ... Gave it a "PUSH" , still stable ...

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You can see how the front tires had spun a little trying to pull me up ... I probably could have just backed up, but I didn't feel like it, plenty of weight on the back, and down low, tires are filled, 70 Lb steel wheel weights on each side, and 275 Lbs mounted on the BH frame, plus the brush hog , rear tires had not broken traction ... Once I added a few rocks, the front tires could steer, and I just drove out!

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I can easily mow this hill sideways in 2 wheel drive with this Kubota, rear tires are not filled, but the MF needs to be in 4X4 ...

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This next picture is the same place as the previous picture, the little tree near the rear tire is the same as the one 10' to the left in the previous picture, with the 5' brush hog I can mow this in 2 wheel drive, but with the 90" finish mower, I need 4X4 to pull it back up, it weighs twice as much, and all the weight is on the ground ... I mow sideways on the hill until I get to that little tree, then go up and down to get beside it ...

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Now it would be interesting to take a 2x4 that's as wide as your tire tracks and lay it across the areas you were concerned about, then stick an angle finder on it to determine the exact angle it was on. Do it in several places if you do it.

 

[stephenh]

People unfamiliar with tractor stability have no clue as to how easily they will roll over. I read a statistic once as to how many people are killed each year in tractor-rollover accidents, don't recall the number but it was humgling.

I traded my first Kubota to a friend for an interest in an airplane and when he and I trailered it to his property, his wife excitedly jumped on it and was gonna drive it down the road to a nearby gas station to top off the tank. I said, take it out of 4 WD for the asphalt street, don't take corners fast, in fact creep around them, don't drive around with the bucket up high, etc. Couple days later, friend told me his wife rolled the tractor first time she went to get diesel when she went hauling around the corner. Did not hurt herself but goobered up the tractor. Sometimes......

 

[ultrarunner]

I hope she doesn’t fly…

 

[dieselscout80]

Retired tractor engineer here. I used to study accident reports. Know that many of the rollover type accidents start as a "runaway" then end in a rollover.

Soooo, pay attention when decending a hill with that load. Diff-lock is the one feature you use  before it is needed. Without, all it takes is one tire to break traction and the other will "freewheel". It feels exactly like you shifted to neutral. Pay attention on decents, slow down, and engage diff-lock before the decent. Good discussion! Hope this helps!

Thanks!!!

I had not thought about using the differential lock on downhills.

I do engage 4wd. Once I forgot to shift into 4x4 with a 55 gallon drum of corn on the loader and slid all the way down, which fortunately was clear all the way down.

 

[LouNY]

A static tip point is all you're ever going to get, I think. Rotational velocity and moment will impact how far you might tip when rolling over an object at speed, but introduces too many variables to be of actual practical use to anyone. Besides, your cheap inclinometers are static instruments, only.

A few years ago at an ag show the Extension service had a tractor cab on a tilting axis. You would climb into the cab and they would tilt it with you sitting in it and then they would ask you to push the button on the wheel at the max that you felt safe at. I have no idea of what equipment tilt that they had compiled their information from. I rode it to a bit over 20 degrees, when I got out they said I was about to the max. I've only been that close a couple of times with larger tractors. A CIH 7120 on one miserable field when chopping with a pull type forage harvester it was an sidehill uphill turn straddling some rock ledges, then on the outher end the turn was to the up hill while coming downhill with a load behind you. It would get your heart to pumping when to stay in the seat you had to move your foot to the low side of the cab.

An inclinometer is an "active" device in that it is providing you with a real time reading.

 

[WinterDeere]

A few years ago at an ag show the Extension service had a tractor cab on a tilting axis.

That's pretty cool. Good demonstration.

An inclinometer is an "active" device in that it is providing you with a real time reading.

It is not, because to be classified as anything other than static, the instrument ramp rate + settling time would need to be an order of magnitude faster than the system it is measuring. Does the bubble on your inclinometer move through the fluid in the sight glass to its final valid position, 10x quicker than your tractor can roll with gravity? Does the digital inclinometer reading ramp and settle 10x faster than 40 degrees per second, or whatever a tractor rotating itself under power might achieve? Almost certainly not.

For an example of the difference, think it it as trying to use a voltmeter instead of an oscilloscope to measure instantenous voltage on an AC waveform. The voltmeter might work for measuring instantaneous time-varying voltage, if the frequency is below 1 cycle per second. But the needle on an analog gauge or the input capacitors on a digital meter will prevent it from doing the same at 10 Hz or 50 Hz. Voltmeters provide a "real time reading", by your definition, but they are most-definitely "steady-state" or "static" measurement devices.

 

[MossRoad]

From what I've heard from some PowerTrac owners that have visited the factory in Tazewell, VA, they have a slope mower sitting on a 45 degree angle in their showroom...