Lift Capacity @ 24" for SubCompacts

[SPYDERLK]

1) WELD a 550lb object to the lower hitch arms. Put it's CoG 24" behind the ball eyes.

2) WELD an 1191lb object to the lower hitch arms. Put it's CoG even with the ball eyes.

Do NOT attach the toplink for either.

Tell me, will the MF GC2400 lift these loads to its maximum rockshaft height?

1] No, The 24" rating is using the 3ph. Without it you get less lift capability.
2] Yes

 

[LD1]

Are you saying in a true //ogram I could place 550lbs a mile behind the tractor and lift it to max capacity?
That is exactally what I am saying provided there is sufficent ballast.




We're almost there together this time........... the above is only true in a closed system. On paper or the blackboard. In theory. But if the tractor does not weigh enough up front, the GC2400 cannot follow this formula IN REAL LIFE.

I have said numerous times that "provided sufficent front end ballast is used". Are you saying you agree with me to this point???

I am not sure why MF rated it the way they did. But 550lbs at 24" is going to take a lot less weight off the front end than ~1200lbs @ the ball ends. So there lower rating is NOT because of that. All that is needed is a FEL and a scoop of dirt and you have sufficent ballast. And if it were a TRUE parallelogram, and that was enough ballast, it would be able to lift the same @ 24" as it does at the ball ends.
Of course not. I'm trying to say MF isn't talking about physics books; they're talking about real life. So when the OP asks why does the amount at 24" go down so much, its because something else in the tractor prevents it. Otherwise MF wouldn't have made it so. If they could JUST change the geometry of the hitch or toplink you can bet your *** they would have!

We have already hashed out the what if's an why's the MF could have used. Bottom line is we dont know for sure. It could be a combination of everything mentioned. So I think we are well beyone the MF debate and just discussing the design of the 3PH in general.

So...In general, Provided the tractor has sufficent ballast (if not, add more), A true //ogram will lift the same amound at ANY point ANY distance behind the ball ends.

The more we shorten the toplink, or lower its front connection on the tractor, It recuces the capacity at ANY point behind the ball ends. The rating at the ball ends remains the same. How much it is reduced depends on 3 things.
1. How far back the load is
2. How much shorter the toplink is
3. How muck lower the toplink is

That is all there is to it. And this can be tested and PROVED in the real world in the methods I described above if anyone cares to try it.

 

[arrabil]

1] No, The 24" rating is using the 3ph. Without it you get less lift capability.

Huh? The weight is on the 3pt arms. So you're saying the toplink is needed for what exactly?

 

[tsteahr]

Huh? The weight is on the 3pt arms. So you're saying the toplink is needed for what exactly?

To achieve the 550lb rating. The lower links are not designed to have something welded to them with the CG 24" behind the link eye. A 3ph was never conceived to be operated in this way. The 550 lb rating assumes the tractor is used as its design intends. This is having a top link and lower links connected to a load such that a mechanical linkage system is achieved.

 

[tsteahr]

Answer to question two is yes.


If ANYONE has a GC2400, could you please measure the length of your lower arm from pin center to pin center, and then measure how far back from the tractor the lift arm is connected. If I had these measurments, I could figure for sure.

OK, I took a couple very rough measurements on my GC. My BH is on right now so I don't have great access to the lower links, but from pin center to pin center is about 22". From pin at the tractor to the lift link connection is about 12".

Using those numbers and a 1191lb @ the ball ends rating yields about 570lbs 24" behind the ball ends (for the question of something welded 24" behind the ball ends).

We cant make a fair comparison between tractors unless we know the available range of motion for the lower links. I don't know of any manufacturer that publishes that spec. So this 570lb number has no real world value.

 

[LD1]

OK, I took a couple very rough measurements on my GC. My BH is on right now so I don't have great access to the lower links, but from pin center to pin center is about 22". From pin at the tractor to the lift link connection is about 12".

Using those numbers and a 1191lb @ the ball ends rating yields about 570lbs 24" behind the ball ends (for the question of something welded 24" behind the ball ends).

We cant make a fair comparison between tractors unless we know the available range of motion for the lower links. I don't know of any manufacturer that publishes that spec. So this 570lb number has no real world value.

What that means is MF grossly underrated the spec @ 24". Why, we don't know. We can only speculate about all the possibilities already mentioned. Like liability, weight distribution, etc.

If you could set your toplink to achieve a perfect parallogram, you would be able to lift the FULL 1191lbs @ 24". If the toplink were able to be lowered to the point that it were on the same pivot point as the lower arms thus negating its effect (Same thing as welding something to the lower arm as it is currently being refered to) you would be able to lift only that 570 lbs @ 24".

Arrabil, do you agree so far???

If so, why is it you cant understand that a toplink position chosen somehwere between these two points is going to yeild a lift capacity somewhere between these two results?

 

[arrabil]

No, I don't agree with you guys AT ALL. Our disagreement is quite simple.... I know the toplink's only purpose is to stabilize the load while you know the toplink provides mechanical advantage. You don't see what I see and I don't see what you see. So we'll just have to agree to disagree cause obviously we aren't getting anywhere.

 

[LD1]

No, I don't agree with you guys AT ALL. Our disagreement is quite simple.... I know the toplink's only purpose is to stabilize the load while you know the toplink provides mechanical advantage. You don't see what I see and I don't see what you see. So we'll just have to agree to disagree cause obviously we aren't getting anywhere.

The toplinks purpose is far more than just stabalizing the load.

The purpose of the topink is to create a modified //ogram linkage system. This does two things, gives a higher lift capacity behind the pins and helps keep the implement as level as possible.

 

[tsteahr]

No, I don't agree with you guys AT ALL. Our disagreement is quite simple.... I know the toplink's only purpose is to stabilize the load while you know the toplink provides mechanical advantage. You don't see what I see and I don't see what you see. So we'll just have to agree to disagree cause obviously we aren't getting anywhere.

Well, I know the top link itself does not provide mechanical advantage, but it is a part of a linkage system that can create mechanical advantage when appropriately configured. But I know what you meant

One last question, Do you have a solid technical basis for your position? You know, like experience in design and analysis of multi-link and truss systems? Or is your position based on your intuitive gut feel, gained from years of working with machines?

Just askin'...

 

[LD1]

ARRABIL: I have a REAL world example for you to try to explain to me.

My tractor, a L3400 'bota, has 24" long lower arms. The lift points are exactly in the middle @ 12" and I have a ball end rating of 1998 lbs.

So, first, would we agree that to achieve this, a force of 3996lbs is required at the actual lift points??

If so, And I did as you suggest by welding a load with a CG @ 24" behind the arms, how much could I lift??

By my math, the load will be 48" behind where the lower arm is connected to the tractor.

12/48=.25
.25 x 3996 = 999lbs would be all I could lift @ 24" if something were welded solid. Do we agree to this point??

So, if the toplink does nothing to increase the mechanical advantage of the system, tell me why kubota has rated the lift capacity 24" aft the pins @ ~1500lbs???????????????