Is there any science behind pucker factor?

[putt_putt_green]

Just wondering if anyone knows the scientific reason for the occurrence of pucker factor?

If I were to guess (I'm sure I'm totally wrong), I'd guess the weight starts to shift from the uphill side to the downhill side of the tractor at a faster rate. This puts less weight on the uphill side of the tractor and more weight on the downhill side of the tractor causing the tractor to shift ever so slightly. This shift is noticeable to a person.

If someone were to drive with one side of the tractor tires loaded and the other side unloaded sideways on a hill, would the pucker factor change based on whether the loaded side was uphill or downhill?

 

[MossRoad]

The weight doesn't shift from one side of the tractor to another. The center of gravity changes.

 

[3RRL]

Scientific reason for pucker factor?...
Self preservation, of course.

 

[SkyPup]

Most Darwin Award prizewinners have low to zero pucker factor.

 

[Soundguy]

Another poster already hit the nail on the head about center of gravity.

And depending on how and where you hang weights.. you will adjust center of cragity on a tractor.

That said.. I'm not a fan of running 1 tire wet, and one dry.

Soundguy

Just wondering if anyone knows the scientific reason for the occurrence of pucker factor?

If I were to guess (I'm sure I'm totally wrong), I'd guess the weight starts to shift from the uphill side to the downhill side of the tractor at a faster rate. This puts less weight on the uphill side of the tractor and more weight on the downhill side of the tractor causing the tractor to shift ever so slightly. This shift is noticeable to a person.

If someone were to drive with one side of the tractor tires loaded and the other side unloaded sideways on a hill, would the pucker factor change based on whether the loaded side was uphill or downhill?

 

[RobJ]

I thought the pucker factor came from the inner ear.

 

[Manitou]

The more pucker factor. The better the grip on the seat.

 

[Reg]

The weight doesn't shift from one side of the tractor to another. The center of gravity changes.

Nope,
Guess again.

The weight and C of G both stay put.
What CHANGES is the area of support UNDER the C of G.
Perhaps more importantly (in our heads) the area of support under our precious little bodies.

and yes, self preservation / fear is the cause.

 

[browns40]

Rob hit the nail on the head with the vestibular system/cochlea/inner ear... we do not like to get off kilter, even by a few degrees, so when a side drops out on us, it's fight or flight that kicks in...

No amount of weight shifting will stop the physiological response, but it can keep you planted more firmly, and increase the actual angle the tractor will go over... this will give you some reassurance as your heart rate continues to spike!

 

[Defective]

I thought the pucker factor came from the inner ear.

But it happens in the inner rear.

 

[RobJ]

But it happens in the inner rear.

hehe, that's effect....I was addressing the cause.

 

[RoyJackson]

If someone were to drive with one side of the tractor tires loaded and the other side unloaded sideways on a hill, would the pucker factor change based on whether the loaded side was uphill or downhill?

Those ballasted tires do lower your center of gravity and add inertia (in this case, resistance to movement, i.e. lifting off the ground).

If one tire was filled and the other not, the empty tire would have less resistance to lifting on a slope (if it was the upslope tire).

The idea of loading one tire to reduce the potential for a side rollover would work in theory, but isn't practical IMHO.

Rob's point about the inner ear is quite pertinent. There are inner ear components (not the right word, bu it'll suffice) that control balance. I know this because I've a problem with one ear.
However, the "pucket factor" is subjective and depends upon the person. I'm sure one could develop a statistical analysis, but that would provide general data, not specific the that individual who rolls his tractor.

 

[MossRoad]

Nope,
Guess again.

The weight and C of G both stay put.
What CHANGES is the area of support UNDER the C of G.
Perhaps more importantly (in our heads) the area of support under our precious little bodies.

and yes, self preservation / fear is the cause.

So the center of gravity never changes?

 

[Egon]

I would think that the center of gravity will change for every change in the longitudinal and vertical axis of the object in question.

 

[putt_putt_green]

The idea of loading one tire to reduce the potential for a side rollover would work in theory, but isn't practical IMHO

This was meant to a theoretical situation. It would be more practical with wheel weights though.

For me, the pucker factor comes on like a light. All of a sudden I feel fine, then whoa, I feel like I'm going to roll over (which is about 16 degrees). I know I feel more stable riding the ATV on steeper slopes (but thats probably because my weight actually makes a difference when I lean into the hill).

So from the above discussion, I would conclude that there really isn't anything one can do to change the pucker factor. But you can change the rollover point.

 

[MossRoad]

So from the above discussion, I would conclude that there really isn't anything one can do to change the pucker factor. ...

Sure there is... condition yourself to ignore it.

 

[RobJ]

Sure there is... condition yourself to ignore it.

Are we reading this? Loaded tires, COG, etc have nothing to do with the pucker factor. It nothing more than a feeling your body is telling mind. Mind over matter. Not to say this will prevent a rollover, but the message our brain is getting usually kicks in long before the tractor is about to roll. Put a tractor on a nice smooth 25 degree concrete slope, get a sample of people to drive it, show them BEFORE a video of the tractor driving on the slope. Some will do it, some will try it, some will not attempt it. Folks have different levels of control.

The highway mowers ignore it because 1) mind over matter, and 2) what helps the mind it knowledge.

Interesting topic.

 

[3RRL]

Here is another thought, like which came first, the chicken or the egg?
Was it the need for self preservation or the inner ear signal?
This could get interesting, indeed.

 

[N80]

I think you are all wrong. Pucker factor has nothing to do with CG, tractor weight, tractor position, operator position or inner ear.

To start with, 'puckering' can be brought on by anything that causes a fear response. Anything that scares you can cause you to pucker. So it is not a response simply to body position or a sensation of falling or rolling. One could pucker, for instance, if something heavy fell next to you, or if someone fired a gun at you, etc. It is completely related to the sympathetic component of the autonomic nervous system. The autonomic nervous system controls involuntary body functions. The sympathetic part of the autonomic nervous system controls our 'fight or flight' responses. This is the same system that causes our hair to stand on end, pupils to dilate, goosebumps, racing heart, etc when something scares us. It is also responsible for brown underwear that has been known to occur in seriously frightning situations and 'puckering' is directly related to that phenomenon.

 

[3RRL]

Hi George,
To start with, 'puckering' can be brought on by anything that causes a fear response.
Curious... I agree "puckering" is related to fear.
What is the primary reason for the "fear response" that causes puckering then?
I think of "puckering" as a feeling that is creeping up on you, like as you approach a dangerous situation rather than (as opposed to) a sudden exposure to one. LOL... I think a sudden one causes shock, then some kind of immediate reaction. IMHO, that is different than the pucker factor. Like a situation you know is dangerous but if you stopped, you could get out of it. Like tracking a wounded lion or getting on a slope that gets steeper and steeper if you keep going. I think it has something to with that kind of feeling, more like a warning system? You would know better than me, so maybe I'm wrong?