Calculating Your Predicted Rollover Angle

[downsizingnow48]

Lots of interesting discussion on an important topic. The static physics surely do need to be understood. And the dynamic aspects (terrain, speed, moving weights) must be properly respected. I scared the xxxx out of myself a few times, having to lower everything to the ground to get an uphill tire down, and then crabbing out inch by inch. What I found out is my need to be out on chancy slopes is a whole lot less than it used to be. That really reduces rollover risk.

 

[Rhino35]

Pat,

A week after I had the spacers installed my father-in-law came over. It was before my physics buddy did the math in my OP. He's been driving tractors since he was a kid. I told him how cautious and fearful I was on the hills (see below) and that even with the spacers my spidey sense was recoiling bush hogging straight across a 15-18 degree relatively flat side slope. I wanted to pick up some rocks where a tracked loader had cleared small trees and big bushes down the hill and needed someone to drive the tractor (since getting off and on the tractor on slopes seems like a really bad idea!) while I walked to each rock and tossed it into the bucket.

We got over to the steep part where I would never (and never will - it is just not necessary!)) attempt a U turn after going uphill to downhill. I motioned for him to back down and instead he just drove sideways across that slope. Later he said he didn't feel alarmed. How steep was it? It had to be 25-30 degrees. And the guy who owned the property before me said he drove his old narrow front axle, two wheel drive, tractor in circles, across the slopes, while bush hogging.

Not me! The spacers are just insurance!

So far the scariest times I've had are almost getting the tractor stuck in mud at the bottom of the hill on Day One of my ownership. I had that sinking feeling when you try and go and one side begins mushing down and you're tilting. And visions of my lifelong rural-living neighbors laughing their *****'es off after pulling me and my new Kioti back up the hill. Probably a couple of decades worth of, "Remember when ol' Rhino got his new tractor stuck the first day he had it? You just can't stomp the city-slicker out of some people!" And then another time I got the front end down into a little creek ravine and thought I wouldn't get it backed out. Both times that little heel pedal that locks the rear wheels into some kind of "can't turn one rear wheel while the other doesn't turn" mode saved me.

I also had a moment going across a side hill, before the spacers were on, where the dirt was a little loose and the tractor started sliding a little down the hill. That was probably on a 15 degree sideslope. I realized that day that rollovers can happen when the tractor slides sideways and the slope steepens. Not to mention even if you don't roll it over you can slide sideways into trees and thick bushes - not good for man or machine.

Thanks for posting.

Rhino

Some shots of the slopes I bush hog.

 

[Sysop]

I also had a moment going across a side hill, before the spacers were on, where the dirt was a little loose and the tractor started sliding a little down the hill. That was probably on a 15 degree sideslope. I realized that day that rollovers can happen when the tractor slides sideways and the slope steepens. Not to mention even if you don't roll it over you can slide sideways into trees and thick bushes - not good for man or machine.

You can also roll in this situation when sliding sideways and the tire on the lower side either piles enough loose soil up it "hangs" or if the tire slides against an immovable object. The momentum of the slide can carry you right over onto your side...

 

[Rhino35]

Sysop,

Yehaaa! I am picturing Slim Pickens in Dr. Stangelove riding the nuclear bomb out of the bomb bay on his B-52.

I agree that encountering a sudden stoppage while sliding is a hazard worth keeping in mind.

I got the industrial tires because I have to drive on lawn to get to a few places. They definitely can slide.

Best,

Rhino

 

[Henro]

Hi,

My take on it is that at the end of the day, calculations are calculations but do not necessarily represent reality, as others have mentioned previously.

The dynamics of one's particular experience is a variable that static calculations cannot take into account.

Static calculations are valuable inasmuch as they show us how to make things better with our tractors. IE, how to increase resistance to a roll over, by setting tires wider, adding ballast and so on.

I think the best we can do is everything that improves our tractor's stability, and maximizes the tractors potential to stay stable when a roll over situation is experienced.

It is important that we do not use calculations of theoretical tip over points to make ourselves more comfortable on slopes. We MUST understand that the dynamics override static theory when operating our tractors.

Calculations are fun, BUT, after you turn your tractor on its side, you come to realize that such things do happen, when in theory they should not.

I would never have expected that sliding a short two foot drop off that I had built up while using my box blade(on nearly level ground) would have resulted in a roll over. Bit it did. Even with foam filled front tires and 75% liquid filled rear tires.

So my advice would be to calculate away, to gain understanding of what will help make the tractor more stable, but NEVER forget that the dynamics of the real world override the calculations of the static theoretical world. I said static...if you can build in dynamics into your model, so much the better. But can you predict what you might encounter on a slope in the worst case? If you can, you may realizes that all the improvements you made will not prevent the worst from happening, if that unpredictable situation comes upon you...

 

[hawkeye08]

Good discussions, not really enough math done to effectively calculate the real world, complex enough with static hill and tractor...

Take away from this thread, be careful on slopes, don't get into a slope more than you are comfortable with and watch out for obstacles (like holes or dips or mounds) that can change things in a hurry...

I'll share a story about my Dad. He grew up in the Palouse region of eastern Washington and was a young man when they were making the transition from teams of horses to tractors for farming. The Palouse is rolling hills and they farmed steep hills using horses. Wheeled tractors had troubles on those hills, but crawlers did better. He actually was a "Cat Skinner" and could drive a tractor with tracks on very steep hills by slipping it sideways. If you just went straight across the hill, you would slide down.

 

[DarkBlack]

Reminds me of that popular comic razor commercial from about 5 years ago with the father showing his son how to shave.
"Up and down like this. Never side to side like this..."

 

[vtsnowedin]

Is there any manufacturer that makes a narrow front end tractor today? Why not?

 

[IslandTractor]

Is there any manufacturer that makes a narrow front end tractor today? Why not?

I believe Kubota makes a special tractor for vineyard and orchard use. Never seen one but recall seeing a brochure or website.

 

[vtsnowedin]

The vineyard tractors are narrow front and back to fit between the rows of vines but there is no point in not having the fronts run in the same track as the rear wheels.