Tires A physics question of leverage

[lennyzx11]

Ok. Stop reading now unless you have time to waste.
I warned you.

My Kubota with AG tires had adjustable rims.
There is about 3-4" of adjustment in the rims.
I just bought wheel spacers that are 3".

Just on the science theory, which way would make the tractor more stable on a side hill?
Say the outer part of the tires touching the ground is 65" as a baseline with both settings.
With the "rim" sticking out past the end of axle or the end of the axle/spacer sticking out past the "centerline" of the tire vertically,
Causing a bit of cantilever. Which would be more stable in respect to the center of gravity overturning the tractor on a side slope.

Yes I know. Both is better.
Inquiring minds want to know. I know some of you will ponder this. **** OCD!

 

[lennyzx11]

BTW. I think it will be equal. When the Center of Gravity swings over the centerline of the tires contact point then it'll tip.

 

[SPYDERLK]

Yes. Same.

 

[dieselcrawler]

Space the wheels wide AND use the spacers... that's more stable! *grin*

Jokes aside, spacing the wheel out with one method or the other, the stability difference is negligible if the final track width is the same.

 

[oosik]

I agree also. Any safe way you can increase the wheel spacing will make the tractor less likely to tip.

 

[RedNeckRacin]

No pondering needed. I agree with the previous posters. Wider is better no matter how you get there. The negligible difference between the location of the rim is more than offset by the terrain changing or other outside factors that are not able to be determined.

 

[CobyRupert]

The one where your tire treads are rotating in the right direction.

 

[N2DFire]

ok - let me see if I have this

Thinking of the Wheel / Rim as a Dish (or cereal bowl) shape and assuming that no matter which way to turn the "dish" both setup's result in the same 65" edge to edge wheel track, you're asking which way would be more stable Dish "Out" (big end to outside) or Dish "In" (big end toward Tractor).

With Dish Out - all (or nearly all) of the longitudinal mass will be between the vertical center-lines of the tires.
With Dish In - a small portion of the longitudinal mass will be on the outside of the vertical center-lines of the tires.

So - in theory - the outside mass of the Dish In position on the low side wheel would act as a counter weight to the (much larger) remaining mass inside the wheel (when you think of the center line of the wheel as the pivot point / fulcrum). In simple terms - any weight placed on the outside of the center line of the down hill wheel will act in opposition to the mass on the inside of the center line.

This would not necessarily move the CG any higher but would move it slightly closer to the down hill wheel.

So - to answer your question - Dish Out would be more stable but the difference would be insignificant in real world application.

If you are really bored and want to have some fun with physics - take a ruler and hang (equal) weights at the very ends, then move your fingers about 2" inside on each end and see how much effort it takes to lift one end (tip the tractor) - this is Dish In

Next swap the weights to the 2" inboard position and your fingers to the outside edges and try to tip it again - this is Dish Out.

 

[ovrszd]

Space the wheels wide AND use the spacers... that's more stable! *grin*

Jokes aside, spacing the wheel out with one method or the other, the stability difference is negligible if the final track width is the same.

I concur.....

 

[AxleHub]

Lenny,

Either spacing method should be similar stability . . but turf tires would be better than ag tires on a side slope.