Front weights or not???

[hotchkiss]

I am sure there are probably similar threads out there, but after looking at the rollover video I have been thinking. I have a new TN95A with the rear wheels set at 83 inches outside to outside. I mow fairly steep slopes that are approximately a 3 to 1 or 4 to 1 slope. With other tractors I can mow them going straight up or straight down, as well as horizontally. If going straight up or down, I always have the loader on and use a 6 foot heavy duty woods brush hog. I am thinking about whether front weights are safer than the loader. I am almost certain that they are, but wanted to poll some members on the safe ways to mow steep slopes. Thanks.

 

[zzvyb6]

If the loader bucket is hugging the ground, its the better deal. Put the weights into IT. If not, then the weights need to be well below the crankshaft vertical height (good rough guess as to center of gravity height).

That will depend on where the front or rear weight bar is/are and how the weights are attached. Its the weight of the loader frame that makes things worse, the lowered bucket gives you a slight advantage. If you are running AG tires, the tractor should slide down the hill before it goes up on 2 wheels. You might want to even test for this. Park the tractor on the hill sideways and put a rope on it at the loader frame at the seat level. If it comes up on 2 wheels that's not safe. If it slides, that's the way good tires are design to work (AG = 'bar' or 'cleat' tires only).

Now there are some who will call this method crazy and stupid, but its what engineers do. Yes the tires are not rolling blah, blah, blah. Ultimately its whether you can get 2 wheel lift on a slope, and what slope does it do this on. Better to know what the answer is, rather than finding out by having your arm caught under the fender.

Notice my preamble to this response did not include the phrase "Now I don't have engineering degrees and I've never been involved in vehicle rollovers and I have no idea what I'm talking about, but it just seems to me that you should hire out this job if the side angle of the hill is greater that 1 inch in 100 feet."

That being said, go play in the field and tell us what you find out. OR, get the neighbor to do the job and take the kids to soccer practice

 

[hotchkiss]

Okay. Let me see if I understand your response. I can understand that if you are going straight up a hill, the loader and the bucket would be the better option assuming it was kept low to the ground. I can also understand that putting weight in the buck would even be better.

However, if you are going in a horizontal direction, I can't help but think the weights would be the better option.

Please give me some more information???

 

[zzvyb6]

The rollover situation is arrived at when the tractor's center of gravity exceeds 1/2 of the average of the front and rear wheel tracks. The sidehill situation alters this ratio because of the shortening (narrowing of the wheel track component. Most tractor weightbars are located at the front lower radiator tie bar height. (Which is about at the crank shaft centerline). Therefore tractor weights are not effective to reduce rollover. They can actually increase its likelyhood because the tires will be more likely to dig in (sidebite increases). Unless you can lower the weightbar, the best thing to do is widen the wheel tracks as far as possible, Most wheels, especially those in the rear, have a reversable spider (part mounted to the axle) and a multiple mount rim. Use this information to balance your need to sidecut the hill and fit thru gates, travel between crop rows, get tire trash tossed at you and turn the tractor in the field with a long tongued implement. One other effective way to lower the cg is to get the weights into the bucket, which you would run at ground level. I do this when mowing first time in the spring so the bucket catches the winter crop of rocks that grow when its cold outside.

Another effective way to keep your shorts clean when on the sidehill is to jack up the tire pressure. This reduces the lug contact with the dirt, making it more likely to slide down the hill rather than tip. I also recommend running split brakes if you have them. This means that some tractors have a link that connects the left and right brakes together under one effective pedal. Lift the link up so that your foot on the left side of the pedal will grab only the left brake. If you sense trouble, stab the downhill side brake. This will put a turning moment on the tractor which will induce a counter roll moment on it. You will turn down the hill, too which reduces the propensity for the tractor to tip up because the effective ratio gets lowered. (Add wheelbase components to the 1/2 track element of the stability margin ratio).

So, things like canopys with heavy lights or music speakers, full keg of beer, heavy hydraulic valve bodies, mufflers, batteries, etc above the crankshaft line increase your rollover potential. Mounting them low or not having them at all improves the situation.

Go to a JD dealer and play with the metal models of tractors. Since its a geometry, and not a mass, problem in physics. You can simulate a rollover situation on a sidebanked hill on the dealer's counter. It doesn't have the engine transmission in it to scale but you will (hopefully) get the idea. Use a piece of string mounted around the fore/aft cg location to simulate the pull of gravity on the side of a tilted parts book.

BTW: hooking your mower up so that the hitch counteracts drawbar twisting also will improve the situation. The drawbar is low, the hitch load is heavy, and the mower is low and flat. Use as thick a drawbar pin as possible so that relative twisting motion is minimized. Note that some hitches, like those on balers and haybines have upper and lower hitch links to prevent additional roll moments from clutch engagement to flop your tractor over. This will definitely help the sidehill mowing situation, too.