Tractor tipping point

[JulianKo]

Hello,

I am new to tractors, so I have no clue where the center of gravity is and how stable they are on uneven terrain. I am very scared when driving on my undeveloped property that the tractor may flip one way or another.
Is there such thing as safe grade angle? I could put inclinometer on the dash and watch it

 

[kthompson]

There are a lot of variables to this. First most likely the tractor will not tip near as easy as you think. Believe most here will tell you they have come out of the seat thinking it was going but it remain upright. Not saying do not be safe, far from it.

You may wish to look at videos on the internet of tractor accidents to get an idea of how far some are pushed before they do roll and they will roll and yes kill.

Some suggestions:
On slopes you are less stable driving sideways, better straight up and down.
Slow is better than fast, a tractor will slower travel over something at high speed that may have bounced crossing and rolled.
Wider wheel spacing is better, check your manual for wheel spacing.
The type of implement you have attached can help make you more stable or less. Wide implements may make you more stable.
Load (even implements) lower are more stable then raised. Of course you must lift them some to transport but if tractor is tipping towards a load, lower it as fast as possible and that may stop the tipping. Say you have heavy load on the rear hitch for front end loader, you drop the load if possible if it tips that direction.
Be sure to keep check on tire air pressure, you do not want a low pressure tire to come off the rim on slope.
Be sure you understand how the brakes work before you get on a slope and you may want to lock so both bake together.
I would suggest you take the tractor only, if it is four wheel drive I would use it and in low gear and slow ground speed with say 15000 rpms so the hydraulics are working pressure and quick response get out there and drive across the different concerns. Begin with one you feel very comfortable with and work up. When you are comfortable at low speed then move up in speed some. Watch you front tires (you will not be able to see rear ones unless in trouble) for lifting off the ground. If that begins to happen-STOP. Land here is mostly level but have had people killed or injured and all the cases I know of were tractors rolling over into ditches (other than accident with auto) or into holes. I really think you will find them much more stable than you think they are. Oh if you have roll bar do wear the seat belt for it should keep you within the roll bar if the tractor rolls. If no roll bar do not wear seat belt. kt

 

[mddorange]

I rolled mine once and it was easier than I thought it would be. It was not even on a hill or incline but a rear wheel dropped into a hole as I was backing up very slowly.
I have had it sideways on some fairly steep slopes without it tipping over and the county mows the right-of-ways going sideways on some fairly steep slopes without any problems around here.

 

[TripleR]

No one really knows, as mentioned just too many variables. This is an often debated topic, here are a few of the past threads:

http://www.tractorbynet.com/forums/owning-operating/199464-slopes-tractor-tilt.html

http://www.tractorbynet.com/forums/safety/183762-how-kill-yourself-without-knowing.html?highlight=

http://www.tractorbynet.com/forums/kubota-owning-operating/279095-mowing-slopes-tractor.html

 

[brown40]

You are correct to be cautious--a performance vehicle, a tractor is not. That said, you can configure some with counterweight and ballast to work at crazy angles, and can usually widen your tire configuration and add weight to lower your center of gravity. On the move is dynamic and less stable... a full bucket on the loader will change the whole equation... cutting across a grade and not planning turns can create some squirrely moments. "Low and slow" is what always runs through my mind when I've got a load or grade that gets the machine more lively. You will also notice something called the "pucker factor" happening just above your seat when angles get tricky.

 

[MESSMAKER]

Beware holes or dips on slopes. You can get in trouble in a hurry. Slow is better when you are on a slope. You have less inertia to get you in trouble. After a while you will develop a feel for what is unsafe. The trick is to get that experience and remain upright.

 

[4570Man]

I wonder what is the maximum safe incline is for the engine. I run my equipment on some pretty steep slopes ( steeper than recommend ) and it just occurred to me I could be starving the engine of oil.

 

[kthompson]

I wonder what is the maximum safe incline is for the engine. I run my equipment on some pretty steep slopes ( steeper than recommend ) and it just occurred to me I could be starving the engine of oil.

This is not meant to be a correct answer but have seen the crazy angles on you tube some run equipment? I have wondered the same thing.


JulianKo, one other point if you are using say a side mount cutter have it on the down hill side of the tractor and low to the ground, will act as stabilizer. If on steep grade would say be very cautious to run a boom mower with cutter head high and extend as it will make tipping easy. Even on our flat land many run rear weights on the side from the cutter head for such attachments. kt

 

[LD1]

Agreed that there are too many variables. All tractors are different, as are widths. And some can have adjustable rear wheels. Whats safe for one wheel configuration might not be safe for another.

I have been on some 25 degree +/- slopes sideways before. Thats about the extent of my comfort.

I'd say 15 degrees should be pretty safe for most tractors. But there is still the chance to roll no matter the slope. A downhill tire can blow, or drop in a hole. Or you make too sharp of a turn uphill.

Static tipping point is pretty high. When you throw in the dynamics of moving......all bets are off. Bottom line.....no matter what anyone says....if you dont feel safe, dont do it.

 

[Gary Fowler]

This is not meant to be a correct answer but have seen the crazy angles on you tube some run equipment? I have wondered the same thing.


JulianKo, one other point if you are using say a side mount cutter have it on the down hill side of the tractor and low to the ground, will act as stabilizer. Even on our flat land many run rear weights on the side from the cutter head for such attachments. kt

I would think that just the opposite would be the right way of doing this. Having the weight on the low side would encourage tipping while having the mower on the high side would make it a counterweight. While it may be something to stop a roll if it is on the low side, it would almost definitely ensure a rollover if on the low side. The mower MIGHT stop the rollover when it hit the ground and then again, it may just fold up.

I would only use them with the mower on the uphill side. Whether that is the optimum way, I suppose that could be debated.

 

[showcattle]

I would think that just the opposite would be the right way of doing this. Having the weight on the low side would encourage tipping while having the mower on the high side would make it a counterweight. While it may be something to stop a roll if it is on the low side, it would almost definitely ensure a rollover if on the low side. The mower MIGHT stop the rollover when it hit the ground and then again, it may just fold up.

I would only use them with the mower on the uphill side. Whether that is the optimum way, I suppose that could be debated.

I agree with Gary. I've mowed steep banks with a sicklebar mower. I feel much more comfortable with it on the uphill side.

 

[k0ua]

I have side hilled a slope at 30 degrees, and it really really sucked. Not recommended at all. I have seen the Mo. Highway Department boys do worse. but their tractors are set up for it. Really wide wheel widths with smaller wheels/tires for a lower center of gravity.

One of the things that gets newby's in trouble is failure to alway keep your Front End Loader as low as possible. I have seen so many youtube vid's of newby's running around with a loaded bucket up high. Absolutely never do that. When you load your FEL bucket lower it as much as possible when you are traveling. I have seen dozens of pictures of rollovers pictures here on TBN, and every one of them had the FEL bucket up high. The tell tale sign of a mistake. Keep the shiny side up, and happy tractoring.

 

[CobyRupert]

View attachment Tractor Overturn Hazards 202[1].pdf

Here's a good brochure on overturn hazards.
Basically, when the tractor's (or any object's) center of gravity (COG) extends vertically over the point of ground contact, it's tipping over.

So...
1) Lower (or keep as low as possible) the COG. (loaded tires do this).
2) Widen the ground contact points (widen tires).

It can be really hard to "eyeball" were a tractors COG is, and it can vary a lot with a dynamic (moving) FEL or attachment. For most tractors, one would guess its around rear axle height.

 

[JRobyn]

I don't think it's been mentioned yet - one thing to bear in mind is that a tractor's front axle is just on a pivot - no suspension - so the only thing resisting tipover on a side hill is the rear wheels. That's why hitting a little dip or hole with the downhill side rear tire can very suddenly flip you.

I have had the FEL bucket (carried very low, as in just skimming the ground) prevent a tipover before.

 

[kthompson]

On the point of which side to carry such as a side mount mower...if I am wrong am sorry...I will stick with load on lower side on this reason, if load in on the uphill side and it starts tipping as the side load gets higher it will help roll you down hill more so than just the tractor by itself. I believe you will find it will speed up the roll as that weight moves higher up. Now I may be wrong there. But this I am 100% sure of, if the cutter's weight is the tip reason and it is on the down hill side and not high in the air as soon as it hits the ground the tipping probably will stop. If on the uphill side and it begins to roll it will roll.

Want to try this in a safe manner, if you have an excavator load it to the max, with bucket run all the way out over one end of it, but only say a foot off the ground and your excavator setting on level ground, slowly rotate the excavator. As you rotate to the side you probably will find the machine wanting to tip and it may very well tip but the second the bucket hits the ground it stops. Why? Because the weight causing the tip was removed from the machine and transferred to the ground. DO NOT DO THIS but take that same load and raise it as high as you can and run same test. Because you have the load so high when it begins to tip the machine probably has so much energy behind the tipping it will most likely continue the tipping action. Ok just go on youtube and watch them. If you could find a video of how a company test the tipping of a crane made to tote a load you will easy see this, same thing with heavy loaded FEL and bucket in the air and you hit the brakes. That is why even here keeping the load low is mention over and over. I worked for a crane manufacture for 10 years, in that time frame worked in many areas but one job I did on occasion was to test load the machines. We loaded them like 110% of stated capacity and then had to run the boom out to where the load tipped the machine. We were trained to keep the load like a 1 foot off the ground at all times I'm the tip test. It never failed when the weight hit the ground the tipping stopped. Now if it was say 50 feet in the air, I would bet the machine rolled.

I will agree if you have a light weight piece of equipment on the down hill side compared to the weight of the tractor and it begins to roll the equipment may be weak enough it can fold up. But that is a tip caused not be the equipment but tractor or hole.

One other crazy reason to me if you are going to run a cutter high in the air I rather have it on the downhill side is I rather have my tractor roll onto it than it fall on tractor with me in or on it. Did not go back to my post but if I did not mention counter weight for down hill implement meant to. If you place cutter on uphill side do you counter weight or not?

I am far from perfect, if anyone disagrees would like to know what is it based upon. kt

 

[kthompson]

To me what is right is more important than being right: I have done a good bit of look at implements on uphill or down hill side of tractor and was shocked to see that sites such as OHSA never mentioned implements. Bu did find two sites, one Liberty Mutual and think the other is Iowa's site that say to keep the implement on the uphill side of the tractor. So I will say based upon this info I am wrong on having it on the down hill side.

We do not have natural long slopes and the slopes I have run any implement on has always been a side mount cutter with it just off the ground and for that being on the lower side has worked well. Matter of fact it has to be on the low side for my use for all I cut on slopes are ditches or pond banks and hard to put the tractor in the pond or ditch and cutter to be on the high side.

I thank those who took me to task on this..but still do the tip test as I explained it for that may help prevent a major roll over for you. kt

 

[kthompson]

Well have done a little video looking and think you may find this interesting: please note this is a test of a tractor not moving, making no turns, no operator and it looks to be widen wheel base and is a low sitting tractor.

 

[TerryR]

Very interesting. Thanks for finding it, KT.

It has verrrry wide tires and low center of gravity. Looks like it is built for side hill operation.

Note also that the front axle is fixed to the engine, rather than having the engine mounted on a pivot point on top of the axle. This makes it more stable since the pivot point becomes the outside of the very wide front tires instead of being in the center line of the tractor. But even so, with the engine being higher than the rest of the mass, the front tips first.

 

[RaydaKub]

On the point of which side to carry such as a side mount mower...if I am wrong am sorry...I will stick with load on lower side on this reason, if load in on the uphill side and it starts tipping as the side load gets higher it will help roll you down hill more so than just the tractor by itself. I believe you will find it will speed up the roll as that weight moves higher up. Now I may be wrong there. But this I am 100% sure of, if the cutter's weight is the tip reason and it is on the down hill side and not high in the air as soon as it hits the ground the tipping probably will stop. If on the uphill side and it begins to roll it will roll.

Want to try this in a safe manner, if you have an excavator load it to the max, with bucket run all the way out over one end of it, but only say a foot off the ground and your excavator setting on level ground, slowly rotate the excavator. As you rotate to the side you probably will find the machine wanting to tip and it may very well tip but the second the bucket hits the ground it stops. Why? Because the weight causing the tip was removed from the machine and transferred to the ground. DO NOT DO THIS but take that same load and raise it as high as you can and run same test. Because you have the load so high when it begins to tip the machine probably has so much energy behind the tipping it will most likely continue the tipping action. Ok just go on youtube and watch them. If you could find a video of how a company test the tipping of a crane made to tote a load you will easy see this, same thing with heavy loaded FEL and bucket in the air and you hit the brakes. That is why even here keeping the load low is mention over and over. I worked for a crane manufacture for 10 years, in that time frame worked in many areas but one job I did on occasion was to test load the machines. We loaded them like 110% of stated capacity and then had to run the boom out to where the load tipped the machine. We were trained to keep the load like a 1 foot off the ground at all times I'm the tip test. It never failed when the weight hit the ground the tipping stopped. Now if it was say 50 feet in the air, I would bet the machine rolled.

I will agree if you have a light weight piece of equipment on the down hill side compared to the weight of the tractor and it begins to roll the equipment may be weak enough it can fold up. But that is a tip caused not be the equipment but tractor or hole.

One other crazy reason to me if you are going to run a cutter high in the air I rather have it on the downhill side is I rather have my tractor roll onto it than it fall on tractor with me in or on it. Did not go back to my post but if I did not mention counter weight for down hill implement meant to. If you place cutter on uphill side do you counter weight or not?

I am far from perfect, if anyone disagrees would like to know what is it based upon. kt

Hi KT,
I appreciate your input. We learn from each other; that's what these forums are all about. I'll take a stab at trying to explain why I believe you are incorrect. As I understand your excavator example above, you seem to equate the lift height of the boom with being on the uphill side. If the hill were a perfect ramp, the bucket would be just skimming the ground whether it were on the uphill side or downhill side. This is not the same as raising the bucket in the air.

The fulcrum of a roll will always be the outside of the track (or rear tire) on the downhill side. Let's assume for the moment that you can't add any weight outside of the width of the machine. If the uphill side of the machine lifts, how do you hold it down? You add weight up hill from the fulcrum but as low as possible. This is why loaded tires are so effective. Now lift that restriction on width. Adding weight outside of the lower side won't hold down the upper wheel. Adding weight outside the upper wheel will hold it down even better than on the wheel itself.

Excavators have extremely strong booms and hydraulics, many to the point that they could do a "handstand" if they had a hand instead of a bucket. This leverage will surely stop a roll as you have noted, but it is because of the leverage, not the cancelation of the weight outside. Tractors and side-mounted implements do not have this leverage. So their downhill-side weight can only serve to lift the uphill side to cause the roll sooner.

Now, in most situations, it isn't the weight that is the issue. It is the uneven application of forces that gives the weight momentum, such as dropping the rear wheel into a hole or hitting a bump on the uphill side. Static analysis will only describe the situation so far. If the tractor were to start a roll, it is doubtful in my opinion that setting that weight down will stop it. Possible, but not as likely.

 

[kthompson]

This has become very interesting to me. I have had no real major slope experience as our ground is without hills and such.

I understand better the cog with an implement on uphill or downhill how it can affect it but I do have a question: lets take a backhoe with outriggers. (Not saying this is proper operation but best way to ask my question.) You lower the downhill outrigger where it is say 6 inches off the ground. Now do you use the low side tire to determine the cog or do you use the outrigger to determine it? Is the outrigger not of benefit to help stop a rollover? Or would running out the uphill outrigger the same amount be of greater value?

Honesty have hard time understanding cutters that are so flimsy they would offer no benefit, on the side mount cutters whether bolted to the tractor or 3pth, those are massive strong implements or at least all I have ever seen. Many are built like outriggers for the weight of the cutter head hanging out there several feet is huge. Do understand sickle mowers are NOT built this way but here have never seen one cutting ditches or pond banks. Then we have a local plant that builds some great side mount hyd cutters. I have no idea what other implement you would need on steep slope. kt