Heavy rear end

[thebuildist]

Actually a question: For traction and stability, what is the minimum weight that should always be present on the rear tires of a loader tractor? I know, "the heavier the better" but hear me out:

Once my bucket is on and working, I intend to build a concrete counterweight. I'll arrive at it's precise needed weight by deduction: The bucket's target payload is 1000#. I need enough counterweight to offset that 1000#, plus "the designated minimum rear tires weight"

I can find the precise offset for the 1000# bucket payload as follows:
First, find the bucket's payload with no counterweight by progressively loading more weight into the bucket until the back wheels of the bare tractor (with no operator) just come off the ground. For example, lets say it's 300#.

On my loader the bucket payload weight is applied at a leverage of 28" in front of the front axle. Since the target payload is 1000#, and the bare tractor counterbalances 300# by itself, then I have 700# payload downforce at 28" leverage distance.

28*700=19600 units.

On the balancing side of the equation, I have
A: Operator weight: 200# @ 48" leverage distance
MINUS B: Minimum designated rear tires weight @ 48" leverage distance (Minus because it hinders our counterbalance efforts, not helps them.)
PLUS C: Concrete counterweight X @ 62" leverage distance.

So IF my designated minimum rear tires weight were 400#, and IF my bare balance pointe were 300#, then my counterweight should be:
19600=(200*48)-(400*48)+(x*62)
19600=(-9600)+(x*62)
29200=x*62
X=471#

Now, the bare balance point of the equation I'll have to figure out by experiment.

SO THE QUESTION FOR THIS GROUP IS:

What is the minimum designated rear tires weight? Surely 100# is not enough for good traction especially on damp grass or a gentle hill.
Is 200# enough? Do I need 400#? Do I need even more than that? What number should I plan for?

I'd love to hear everyone's thoughts.

Thanks,

Bob

[Eugen]

Isn't that a LOADED question Bob?

These are my thoughts. Traction is a function of tire profile, surface characteristics, and finally the force between tire and surface, which is a result of the weight pressing the tire down. You go on wet grass with bald tires on a little incline and you can have 10k lbs on those tires.

One of my intended uses for the tractor has always been garden duty. So I did some searches in relation to weight and Ag tires. I first tilled my garden with a 220 and turf tires and it became very clear very quickly that Ag tires are needed. I came across an article tackling the issue of weight and farm tractors (I'm sorry I don't have the reference). From the article: too much weight on the rear is counter productive for a farm tractor, you end up with a light front. Too much weight overall and you consume more fuel than you should. Somehow the conclusion of the article was the rule of thumb that you need to weight the tractor both front and back with as much weight that should the traction tire slip, it should slip no more than over one tire lug (or the distance between two lugs on the tire).

Most anecdotal evidence around the garden tractor forums also point out that for snow duty chains are a must, besides "enough" weight.

For garden, especially moldboard plowing, I concluded for myself that Ag tires on the 446 (and now on the 644) were needed, and though I intended to use the larger combine weights (162 lbs each) on the tires, being in a hurry I installed the smaller combine weights (104 lbs each). They seemed adequate, although in some instances one of the tires did slip. I like to plow the garden much deeper than it's normally recommended, so it's especially hard for the tractor at times, and it gets stuck. Would more weight help in this situation? I'm not sure, there was some evidence that the 14 HP on the 644 gets bogged down when the plow is stuck and there is enough traction on both tires.

For snow duty I have not had problems with the 446 and turf+chains, not at all. At the time I had no tire weights.

Now, loader duty. In the last 2 weeks my 644 went through almost 13 tonnes of gravel mixed with screening. Before that I did quite a bit of wet sand. Now I have 8-16 Ag tires on the rear of the 644, with the 104 lbs each combine weights, and a weight box at the back with about 300 lbs of steel. Weight of the operator somehow does not matter in this equation I can tell you this, that without the 300 lbs box at the back I was able to work sand, lift, and steer without much of a problem. However, with the full weight box at the back the most noticeable effect was, in my opinion, that I could push into the gravel pile further than without, and thus load the bucket with more material. Perhaps the steering was also a little easier.

For such tasks I'm not very fond of formulas, though I welcome a good discussion on it. I found it easier to put the weight that I was able to put without too much aggravation, but boy do I like those combine weights, consider myself lucky to find them. Also, for loader duty, a weight box I'd consider a priority to fabricate, if I didn't have one.

[Jancoe]

In the owners manual for the loaders it states that you should have 500 lbs on rear to use maximum front loader lift capacity.

Sent from my SM-G975U using Tapatalk

[thebuildist]

In the owners manual for the loaders it states that you should have 500 lbs on rear to use maximum front loader lift capacity.

Sent from my SM-G975U using Tapatalk

Excellent info! I did not know that before. So if I assume that my weight & balance is similar to the 64X series, then I could just put 500 lbs and call it a day.

Thanks!

[crazycase]

HI Guy
What tires are you running on your loader ?

If you could fide a set of D-10s for your rear rims
and if you had a 3-point out back you could hang something like this on your 3-point

also here is the weights you can hang on the bar Weight - Suitcase John Deere Click image to open expanded view Weight - Suitcase John Deere Brand: All States Ag Parts 4.4 out of 5 stars 18 ratings | 3 answered questions [attachment=0]image.png

[thebuildist]

Isn't that a LOADED question Bob?

These are my thoughts. Traction is a function of tire profile, surface characteristics, and finally the force between tire and surface, which is a result of the weight pressing the tire down. You go on wet grass with bald tires on a little incline and you can have 10k lbs on those tires.

One of my intended uses for the tractor has always been garden duty. So I did some searches in relation to weight and Ag tires. I first tilled my garden with a 220 and turf tires and it became very clear very quickly that Ag tires are needed. I came across an article tackling the issue of weight and farm tractors (I'm sorry I don't have the reference). From the article: too much weight on the rear is counter productive for a farm tractor, you end up with a light front. Too much weight overall and you consume more fuel than you should. Somehow the conclusion of the article was the rule of thumb that you need to weight the tractor both front and back with as much weight that should the traction tire slip, it should slip no more than over one tire lug (or the distance between two lugs on the tire).

Most anecdotal evidence around the garden tractor forums also point out that for snow duty chains are a must, besides "enough" weight.

For garden, especially moldboard plowing, I concluded for myself that Ag tires on the 446 (and now on the 644) were needed, and though I intended to use the larger combine weights (162 lbs each) on the tires, being in a hurry I installed the smaller combine weights (104 lbs each). They seemed adequate, although in some instances one of the tires did slip. I like to plow the garden much deeper than it's normally recommended, so it's especially hard for the tractor at times, and it gets stuck. Would more weight help in this situation? I'm not sure, there was some evidence that the 14 HP on the 644 gets bogged down when the plow is stuck and there is enough traction on both tires.

For snow duty I have not had problems with the 446 and turf+chains, not at all. At the time I had no tire weights.

Now, loader duty. In the last 2 weeks my 644 went through almost 13 tonnes of gravel mixed with screening. Before that I did quite a bit of wet sand. Now I have 8-16 Ag tires on the rear of the 644, with the 104 lbs each combine weights, and a weight box at the back with about 300 lbs of steel. Weight of the operator somehow does not matter in this equation I can tell you this, that without the 300 lbs box at the back I was able to work sand, lift, and steer without much of a problem. However, with the full weight box at the back the most noticeable effect was, in my opinion, that I could push into the gravel pile further than without, and thus load the bucket with more material. Perhaps the steering was also a little easier.

For such tasks I'm not very fond of formulas, though I welcome a good discussion on it. I found it easier to put the weight that I was able to put without too much aggravation, but boy do I like those combine weights, consider myself lucky to find them. Also, for loader duty, a weight box I'd consider a priority to fabricate, if I didn't have one.

I appreciate the input and advice. It sounds like 500 lbs might be the consensus of overall counterweight. The only modifier being "how similar is my machine's weight and balance to a factory Case/Ingy loader?"

Bob

[thebuildist]

I just went and looked in 644 the manual, and it calls out the payload capacity as 600 lbs. I'm guessing its actual capacity is greater than that and they're just being conservative?

Otherwise if I really want a 1000 lb payload, it looks like I'll probably need more than 500lbs on the back end.

meanwhile, if I make some assumptions, I think I can deduce the axle weight on a 600lb loaded 644

Assume: the bare tractor can pick up 150lbs with no counterweight.
full payload times 28 inches leverage equals A: Operator weight at 44 inches leverage PLUS B: 500 lbs counterweight at 50 inches leverage MINUS C: Axle weight at 44 inches
(450*28)=(200*44)+(500*50)-(X * 44)
X=481 lbs.

So a factory 64X at its full 600 lb load, with its specified 500 lb counterweight has around 481 lbs on its rear axle.

If I plug that into my formula I get 534 lbs. (less than it otherwise would have to be, becuase the counterweight is slug farther back between the 3-pt. arms, 62 inches behind the front axle.)

That's certianly reasonable. So unless I hear evidence otherwise, I think I'll use the 481 figure as my target minimum rear axle weight.

Bob

[thebuildist]

HI Guy
What tires are you running on your loader ?

If you could fide a set of D-10s for your rear rims
and if you had a 3-point out back you could hang something like this on your 3-point

also here is the weights you can hang on the bar

Weight - Suitcase John Deere
Click image to open expanded view
Weight - Suitcase John Deere
Brand: All States Ag Parts
4.4 out of 5 stars 18 ratings | 3 answered questions
[attachment=0]image.png

I'm running the standard Carlisle turf tires that came on the 4020. If you're afraid of getting whiplash from your rear wheels digging in and shooting you forward, then these tires are SUPER SAFE.

I do have chains for them, and I will consider them absolutely necessary for the slightest loader work on anything but concrete.

[Eugen]

You gotta consider though, why all the 6xx loaders were equipped with a different type of tires than turf.


Without realizing I do have about 500 lbs of weight on the back.

Now, the bucket capacity on the 6xx is supposedly 4.7 cubic feet. What capacity will your bucket have?

[thebuildist]

It's a 48" bucket with 5.15 cubic feet volume. Its shape is less than ideal, as it has a lot of rear projection, which leaves the bucket mounted farther forward from the loader arms than I'd like it to be.

I'm considering modifying the bucket to cut off some of its rear projection, so that I can move the load backward towards the arms.

I haven't decided yet if it's worth the hassle/work to do it.
What are your thoughts about that?

Bob