More is better...Less is better...

Anonymous Poster · Jan 29, 2003

Hi,

In a post here

rdbrumfield wrote:

I for one do not use fluid in my tires or added weight beyond a normal emplement on the 3pt.
...when we get that loader filled to capacity, to the point that the back gets light, that little front end is taking on the total weight of the tractor plus anything we pile on it.

In my mind Randall is absolutely correct, once the rear wheels leave the ground, or even when that are starting to.

But, when they stay on the ground, they can work as a pivot point, and anything you hang on the back side of them will tend to make the front end lighter and counter the weight of the loader and what is in the bucket.

Imagine putting something REALLY heavy on the 3PH. In theory you could put enough weight on the back to make it impossible for the front wheels to come up off the ground.

Maybe this has all been covered before...Glad Randall brought it up though, cause I had not really thought about it. I wonder if there is a difference in the practical world. I mean regarding the front end loading felt by the front axle.

The only time I lift my rear end up is when I have the bucket on my B2910 stuck into something. Like a stone in a bank, or say a root of a stump I am trying to get out.

In this case, the force felt by the front axle is not caused by what is in the bucket, but rather by the hydraulic force of the loader. Now if my tractor is light in the rear, the back lifts and I stop that, by backing off on what I am doing. AT that point, the full weight of the tractor is on the front axle.

Now if I hang something heavy on the back, enough that it will not come off the ground [or ballast the tires, etc], then the full force of the hydraulics will be felt by the front axle, and to the point where the pressure relief valve operates, and the front axle will be strained more than when the rear came off the ground [I think].

Randall, I think this is what you are referring to.

BUT, when the tractor is carrying a load on/in the front loader, I think the situation is different. Weight on the back seems like it should be a positive.

Viewing the rear axle as the pivot point, any weight on the front side would be felt by the front axle, and any weight on the rear side would tend to counter balance the weight on the front, and take weight away from the front axle. Any weights/ballast added to the rear tires would probably cancel itself out, since half would be on each side of the axle.

I guess the bottom line is that like Randall says, IF you can get into a situation where you bring the rear wheels off the ground, ALL the weight is carried by the front axle and all the driving power is transferred by those gears.

But if the extra weight added to the rear keeps the wheels on the ground, then it is to the tractor's advantage, rather than otherwise.

So what am I trying to say???

MORE WEIGHT ON THE BACK IS BETTER...IF you CAN keep you rear wheels on the ground

LESS WEIGHT ON THE BACK IS BETTER ...IF you CAN'T keep you rear wheels on the ground

At the moment this seems to make sense to me...is my logic flawed?

Bill in Pgh, PA

rdbrumfield · Jan 29, 2003

Bill;
I see your point about weight on the 3pt taking strain off the front axle, but look at it this way.
Consider the moment and arm of the back tire, and then consider the moment and arm of the front axle with all the added weight. Sure it does lighten the front a tad, but the main effect is to hold the back down from the moment of the front axle. That little front axle is still carrying the total load in balance. Then consider that when the loader is stopped and not being lifted, so the relief is not in the system, then going over rough ground, the shock load far exceeds the limits of the loader capicity.
Over the years I have noticed that designers have beefed up the fron axles on these small tractors due to the fact that most are sold with loaders. The first Kubota I bought I remember going through a couple of front rims and broken lug nuts. Broke out the centers. Wish I still had that tractor, sure was a handy little machine.

BillyP · Jan 29, 2003

Here's the way I look at it.

Your using your FEL with no ballast. You have say 2,000 lbs. of wet clay in the bucket. Your rear end comes up. Say for instance that 2,000 lbs. is what it takes to teeter tooter the tractor.

Your using your FEL with 1,000 lbs of ballast on the back. You have 2,000 lbs. of wet clay in the bucket. Your rear end stays down because of the ballast. But your front end is still carrying the same weight, plus part of the 1,000 lb ballast.

I believe the front axle takes the most punishment while moving a heavy loaded FEL. Ballast the rear, drive according to terrain and don't get the front bouncing.

That's my story and I'm stickin to it. /w3tcompact/icons/laugh.gif

Billy

rdbrumfield · Jan 29, 2003

I'll go with that Bill. Just remember, 2000 in the bucket with the back light is 4000 on the front end.

Anonymous Poster · Jan 29, 2003

I think when your rear wheels come off the ground the front are carrying everything. The entire weight of the tractor and the weight of the load in the loader.

Now if you put weight on the back, behind the rear wheels and they stay on the ground, the front axle will not feel any downward force due to weight behind the rear axle, but instead will feel a reduction in downward pressure due to the see-saw effect pivoting on the rear axle.

I can't see anyway that ballast behind the rear axle can add weight to the front axle, as long as the rear wheels stay in solid contact with the ground.

How can weight added behind the rear axle increase the downward pressure on the front axle?

I can't see that happening unless you hit a bump moving and cause the rear wheels to bounce into the air...

Now a follow up question. Say your tractor is stitting there and you put 1,000 lbs in the loader. How much does this increase the downward pressure on the front wheels? Looks like the front axle would feel more than 1,000 lbs. How much depending on the geometry. Seem reasonable?

Bill in Pgh, PA

beenthere · Jan 29, 2003

""MORE WEIGHT ON THE BACK IS BETTER...IF you CAN keep your rear wheels on the ground ""

I would just change your line to:

MORE WEIGHT ON THE BACK IS BETTER...SO you CAN keep your rear wheels on the ground

The front ends of the CUT's are designed to handle the load, so I don't worry about anything other than picking up whatever the bucket (FEL) will pickup without the rear wheels coming off the ground (that is when it becomes dangerous).

rdbrumfield · Jan 29, 2003

You are right in both cases.
You can figure the amount of weight on the front caused by the loader. Would have to know the distance from cg on the front tire 'moment' to the cg of the bucket 'arm' and of course the weight in the bucket. I should know this stuff by heart being a pilot, but I don't use it with the small planes, never load them down.

RayBee · Jan 29, 2003

My experience moving heavy loads with the FEL is to go slow, to not jar the load thus creating more stress and harmful momentum. /w3tcompact/icons/shocked.gif I also feel that loaded tires contribute greatly to tractor stability by grounding the rear ......WITHOUT adding weight to the tractor. As long as the rear makes contact with Mother Earth the weight of the tire ballast isn't carried by the tractor. (My 2 cents)/w3tcompact/icons/smile.gif /w3tcompact/icons/smile.gif ..RayBee

Wingnut · Jan 29, 2003

good point!! The ballast in the tire isn't "pulling the tractor down" ... so it's far superior to adding weight to the tractor frame.
By the way ... that brought to mind the old "gravity is bullpatootie, the earth sucks" homily. /w3tcompact/icons/laugh.gif

pete

BillyP · Jan 29, 2003

OK Bill, I concede. /w3tcompact/icons/grin.gif

It's like putting too much weight on the front part of a trailer. You're driving down the road, hit a bump and the weight of the trailer makes the front of your truck bounce up.

On tire loading. It is a good ballast but not always the best. When you load your tires, you're stuck with it. You can't (or won't) remove the ballast when not needed. Although tire loading doesn't add to axle weight, it does add to drivetrain stress (not much but some). I use my bush hog for ballast. When I'm not going to be using the FEL, off it comes. There's no need in carry extra weight for nothing.

Billy