Tires Loaded Front Tires Resist Tipping?

Henro · Apr 1, 2004

Hi,

A while back there was a thread related to loaded tires and tractor stability on slopes. It is accepted that loading the rear tires will make a tractor more stable on a slope, especially a side slope.

Someone in the tread I am thinking of posted that since the front axle is on a pivot point, that the tractor would tip the same whether the tires on the front were loaded or simply air filled.

At first thought this seemed reasonable. So I wrote off the added weight of my foam-filled front tires as being of no worth, as far as side-slope stability and roll over prevention goes.

This morning I turned my brain on and now think that the extra weight of my front tires does in fact add to my tractor’s side-slope stability and would help fight against a side-slope caused roll over.

This is because the front axle and tires hang from the center pivot point, and if the tractor started to tip, it would have to lift that weight off the ground, just like the rear axle is lifted. This weight may, or may not, come into play before the end stop on the front axle is reached. But it would have an effect.

So my conclusion is that the weight of the front axle, and the tires attached to it, do indeed affect tractor stability.

Is my thinking flawed?

BigAl · Apr 1, 2004

Hi Henro ,
I don't know if your thinking is flawed or not, but awhile ago there was a Aussie fellow who posted a thread about this . He swore by loaded front tires . I never gave it much thought ,as I usally only had the rears loaded on my tractors in the past . On my new tractor I had the front and rears loaded . I really have not had much chance to evaluate front loaded tires ,since this was done . That will come this summer on the old ranch.
Big Al

Poppa · Apr 1, 2004

Henro, I think loaded tires would have to help. Anything put BELOW the center of gravity is going to help lower that CG and make the tractor more stable. Does it help a lot? Well, that is math and I don't like math but it sure can't be hurting.

Mike

rockyridgefarm · Apr 1, 2004

Good news, Henro!

The TBN/PSU tractor rollover research project is going to answer this very question. We will be performing tests THIS WEEKEND. And the good news gets even better, because the test are to be done on equipment very similar to yours and terrain very similar to yours. And very near you, no less.

Wait, it IS your equipment, at YOUR House...

What's for lunch?!!!!

/forums/images/graemlins/grin.gif

btw, i am in agreement on the cg side, but i also think there are possible situations where loaded tires COULD add to instability, like on a pond dam.

RonR · Apr 1, 2004

Henro, do you have any other hobbies, besides making everyone here engage their brains a lot?????? /forums/images/graemlins/cool.gif /forums/images/graemlins/cool.gif /forums/images/graemlins/cool.gif /forums/images/graemlins/cool.gif /forums/images/graemlins/cool.gif

Why my daughter was 2ish, she asked so many "WHY" questions, I had her trained when she met someone new to say "Hi, my name is Cindy, and I'm in the WHY stage." It was cute for everyone!

Best wishes, and keep the hard questions coming. /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

BB_TX · Apr 1, 2004

Henro-I agree with you to some extent. I don't think the extra weight would have any effect at all until the tire actually started to lift. Up to that point, it is not providing any down weight to the tractor frame since the axle is pivoting. The tractor is still providing down force on the wheel rather than vice/versa. At the point the wheel starts to raise, then real weight is transferred to the frame itself. Whether that would be enough to stop the rotational motion of the tractor would be different for all situations and essentially indeterminate. /forums/images/graemlins/crazy.gif

Poppa · Apr 1, 2004

BB's right on. The added weight of the tire would not become a factor until the rolling motion of the tractor began to lift that wheel off the ground. Therefore anything other than a straight back flip would be adding the weight of only one of the filled tires to the tractor. So, it seems to me that the question is, if the minor (relative to the tractor as a whole)amount of added weight from the ballast in the smaller front tire would have enough effect to stop and reverse the rolling motion of the tractor.

Hope not to find out /forums/images/graemlins/grin.gif

Mike

Bob_Skurka · Apr 1, 2004

BB . . . I generally agree with your points, but would think that the effect of the loaded tires (front or rear) would differ depending on the slope the tractor is traversing.

Taking my theory to the extreem I believe we should put Henro's tractor on a 45-degree slope and see if the the center of gravity is above or below the loaded tires that are on the high side of the slope. It is very possible that, depending on the steepness of the slope, the C-O-G could be below the loaded tires that are on the high side of the slope and the loaded tires could actually increase the chance of a rollover.

JASTN70D · Apr 1, 2004

I believe that the more weight the tractor would have to lift below COG in order to side roll the more force it would take to roll I. E. More stable. How much more stable is the question not if.

JerryG · Apr 1, 2004

How is it going to help stability UNTIL the axle hits the stops?

Ledgemere Farm · Apr 1, 2004

Are you talking about loaded tires + an FEL? I would be worried about putting extra stress on my axle and MFWD. Sounds like a good recipe to break something. /forums/images/graemlins/crazy.gif

beenthere · Apr 1, 2004

Henro.
You are correct in your thinking.

PineRidge · Apr 1, 2004

<font color="blue"> Henro.
You are correct in your thinking.
</font>

Please don't tell him that.... he will ask another question /forums/images/graemlins/crazy.gif

I would think that by the time the front axle hits it's stop the extra weight doesn't really matter because it's going over anyway.

Lazy · Apr 1, 2004

Hi
I have tipped over several times when I was loaded.. /forums/images/graemlins/grin.gif

Larry_T · Apr 1, 2004

The more weight you have on the ground the better,especiall when you lift bucket up high. I think you are right. Larry

Theowegian · Apr 1, 2004

Interesting thread.
So, is it possible that IF the front tires are filled, then maybe you dont need suitcase weights on the front, when using a rear attachment like a rotary cutter? Assuming that there is no FEL attached, of course.

Just wondering....
dwight

Henro · Apr 1, 2004

OK...here is how I see it at the moment.

Adding weight by loading the front tires probably will not cause a tractor to tip more easily.

In the case of a potential back flip, the added weight will be 100% beneficial.

In the case of a side slope, that tilts 90 degrees perpendicular to the frame of the tractor, the extra weight of the front tires, wheels and axle probably does not help until the axle bumps the stop on the down hill side.

At any point between directly backwards and 90 degrees perpendicular to the frame, the added weight of the front tires, wheels and axle will have some beneficial effect, which will lessen the more the slope angle approaches a line drawn between the operator’s shoulders.

The weight of the tires, wheels and axles on the front will do nothing to prevent a hand-stand wheelie…

Please let me get my head protector thingee done before we put my tractor on the 45 degree slope with Bob S in the driver's seat... /forums/images/graemlins/grin.gif

Henro · Apr 1, 2004

<font color="blue"> It is very possible that, depending on the steepness of the slope, the C-O-G could be below the loaded tires that are on the high side of the slope and the loaded tires could actually increase the chance of a rollover.
</font>

Bob, I don't think this is possible. However, it does bring up a very interesting concept. Variable C-O-G position!

We probably should reserve this for a seperate thread though. I'll bet it could be proven that as the tractor rotates about the front axle pivot point, that the center of gravity of the tractor's mass changes relative position within the total mass.

Junkman, where are you when we need you???? /forums/images/graemlins/grin.gif

Slamfire · Apr 2, 2004

Me too, Lazy. I thought I'd set a world record one night in Boston, when the whole paddy wagon tipped over. /forums/images/graemlins/crazy.gif

Doesn't the stabilization of the loaded uphill tires, get degraded by the weight of the downhill tires?