Rear Counter Weight

[LD1]

I am not an engineer but I believe it depends on where the center of mass is.

I believe your scenarios are only correct in the case where the rear wheels lift off the ground.

No....my scenario is correct regardless.

Take my second example of 500# ballast, 2500# tractor, and 800# up front and rear wheels in the air. Total weight is 3800 all borne by front axle.

Now take 5 pounds out of the loader. Just enough so rear tires touchdown.....

You still have WAY more load on the front axle than with no ballast. Simply because the loader can lift so much less.

While my numbers are just examples and not real world numbers for any specific machine....the theory is 100% correct.

 

[Branson Bob]

No....my scenario is correct regardless.

Take my second example of 500# ballast, 2500# tractor, and 800# up front and rear wheels in the air. Total weight is 3800 all borne by front axle.

Now take 5 pounds out of the loader. Just enough so rear tires touchdown.....

You still have WAY more load on the front axle than with no ballast. Simply because the loader can lift so much less.

While my numbers are just examples and not real world numbers for any specific machine....the theory is 100% correct.

I believe once the rear wheels touch down that the center of mass starts moving to the rear of the front axle.

But rather than debate it, I'll ask an engineer I know how he sees it.

 

[LD1]

I believe once the rear wheels touch down that the center of mass starts moving to the rear of the front axle.

But rather than debate it, I'll ask an engineer I know how he sees it.

That part is correct.

The center of mass starts moving rearward.

But with a max load I. The loader and only barely enough weight to keep the rears planted....the center of mass is still WAY too far forward.

Curious to see what your "engineer" friend says. He will either agree with what I said or he will be wrong

 

[4570Man]

I believe once the rear wheels touch down that the center of mass starts moving to the rear of the front axle.

But rather than debate it, I'll ask an engineer I know how he sees it.

You’re right but how much ballast would you have to add to reduce the front axel load at max lift capacity to less than the front axel weight with no ballast at all? The answer is an unreasonable amount. Much more than a simple 800 pounds ballast box.

 

[ning]

Exactly what I am saying.


Say you are digging into a pile or a stump...and with no ballast the back wheels keep coming off the ground right.....

Now let's say the tractor weighs 2500#....and is able to expert (lift) 500# before the back wheels hike into the air. That would make 3000# all be on the front axle right......

Now let's add 500# of ballast. And that is enough to make the loader lift 800# before the rears lid in the air now. (Insufficient ballast). But now the 2500# tractor, 500# ballast, and now 800# load is all on the front axle. Total of 3800#.

So let's increase ballast to 1000#. That can now make our loader lift 1100#. AND the rears stay planted but barely....and only retain 500#.

So the 2500# tractor, 1000# ballast, 1100# load is now the total weight of the machine at 4600#.....but still 4100# on the front

Adding ballast/counterweight only adds to the "potential" loading of the front axle. But only up to the point of ENOUGH weight on the back to actually start unloading the front axle.

But this varies by tractor and loader lift capacities. With "just" enough ballast to max out the loaders lift capacity yet have next to zero weight on the rears is the worst case scenario. Because from that point onward any addition rear ballast will shift the fulcrum back to the rear axle and start unloading the front axle. But until that happens.....you are only adding to the potential front axle load

I get it. Good point, A+

 

[Citydude]

Just by personal experience, rolling a front tire off the bead while unloading an 1100# snowblower off my trailer, LD1 is correct. Lol

 

[Branson Bob]

In the interim here's an excellent video that discusses in great detail the conversation we're having about the physics of 1) rear ballast, 2) rear wheel ballast (weights or Rim Guard), and 3) FEL payload.

It's a simple engineering discussion known as a "beam analysis."

The video starts with him using his tractor to identify the forces. At 6:30 he goes to the computer and at 10:30 he presents the formula which is central to the discussion.

At 19:10 he goes over some examples.

He doesn't address the scenario where the rear axle is lifted off the ground or the scenario where the rear wheels are barely on the ground but that can be extrapolated by those with good algebra skills and a bit of time on their hands.