Lift capacity of 3-pt hitch question (plz keep it simple)

[LLS]

Sodo, to answer your question on the 2000# of weight I lifted, I used a very complex math equation of 40 bundles of mulch on a pallet that weigh 50# each = 2000# haha. As far as where that weight was on the pallet it was a big cube on a standard size pallet.

 

[LLS]

My b2320 would not lift a 770# seeder with a quick hitch on but with it off it will lift it with the extra 4" closer to the tractor.

 

[LD1]

My b2320 would not lift a 770# seeder with a quick hitch on but with it off it will lift it with the extra 4" closer to the tractor.

Something like that, where you know you are right near the max, is a great time to play with toplink position and length to see the effects it has first hand.

My heaviest implement is a 1100# bushhog, and I can lift it fine in any position of my toplink. If I had anything heavier I would do something like that myself. Find something that Is just heavy enough I cannot lift with the toplink in the bottom hole, them move to the top hole and watch it lift.

 

[Sodo]

1100 lb bushog with a good ole' boy sittin' on it! :laughing: :laughing: : laughing:

 

[ishiboo]

Good LLS! Page 2 and the question is still apparent to some !

How do you know the pallet is 2000lbs? And if that weight's accurate, can you find 450 lbs to add to the pallet? Couple of good ole boys?

Reason I asked for 1500 lbs is (in general) a 35 HP tractors can probably lift anything it needs to. Under 30hp is where there's more of a need to know what the ratings mean with regards to 3-pt pallet forks. How about put the forks on the 2320 and lift a few good ole boys (who don't lie about their weight like wimmin' :laughing: )?

Huh? All your posts are twisted and confused. There is no 35hp/30hp magic cutoff, this isn't a simple answer other than yes - a 3 point hitch rated for 1500lbs, can lift... 1500lbs. Can it lift "a pallet with 1500 lbs on it"? The answer is a solid maybe.

The lift spec DOES matter, as much as you want to ignore it.

A tractor that has a 1500lb lift capacity AT 24", should be able to lift at least 1500lb of weight 24" out.

A "pallet" is not a unit of measure. If that pallet has 1500lb of concrete at the far end, and none towards the tractor, it's unlikely it can lift it.

1500lb at the pins and 1500lb at 24" are completely different specs. Of course, if it's 1500lb at 24", it can do more than 1500lbs at the pins.

Toplink geometry, tractor RPM, reliefs, etc... all come into the picture to find an exact value.

 

[LD1]

1100 lb bushog with a good ole' boy sittin' on it! :laughing: :laughing: : laughing:

Done something similar a few years ago.

Was experimenting with FEL lift capacities and a pair of 550# big game scales as well as a2:1 block and tackle setup (to measure up to 2200#).

With the contraption I had to have the FEL ~5' high, and was on a slight slope. Combination of lift and curl I was able to pop a rear tire up. I threw on a ~150#+ chunk of firewood on the back of the hog. Still had no issues lifting it. So probably ~1250# @ 36"+ load center. And that was in the bottom hole to for the toplink. I cannot load it on my trailer unless I am in the bottom hole which causes the tailwheel to raise alot higher.

 

[SPYDERLK]

http://www.tractorbynet.com/forums/...ion-factor-3ph-load-capacity.html#post1682683

 

[CDN Farm Boy]

Interesting read and the 9 pages of the thread Spyderlk linked also. There is a whole lot of "engineering speak" of how & where the forces act within a 3 pt hitch. While I'm not an engineer, I can mostly follow the theories and that they aren't completely over my head. Is it a simple question to answer with absolute perfection? Nope, that's pretty evident. Can it be dummed down enough for the average person? Sure, as long as they understand they are using simplified math to do so and some loss of accuracy is inherent in doing such. LD1s ratio is probably the easiest to use BUT that only works if you have the dimensions to get the ratios. In a practical sense, we are typically limited by either a) the hyd force on the lift arms or b) weight on the front of the tractor.

To Sodo's point about loading to the max with known numbers I can add my experience:

Kubota B3300SU
My manual spec is 1786 lbs @ lift points and 1400 lbs @ 24" behind lift point. I am unsure if "lift point" means the end of the lift link or the ball end.
My manual also states (under the "implement limitations" section) a max loading on the lower link ends of 800 lbs and a chart of max implement weights with 550 lbs being the highest
I have 2 toplink holes and am using the top hole. Manual says top is standard and "lower hole is only used when some obstacle prevents you from using the standard"
I have an 850 lb LPGS build thread here that is 5' long with the COG roughly in the center of it plus 3.5" of hitch brackets
I have started using a quick hitch with it this summer which pushed it back about 4.5" and weighs about 75 lbs (online number, not actual....I suspect it is lighter)
I have 2 choices on my lower links to attach the lift arms which I am using the higher lift/lower capacity setting
Dimensions of the lower links are (from their pivot on the frame) 10" to the lift arm now, 12" to the other hole, 21" to the ball end.
It was -27C this morning so getting those measurements was the best I can do for now, I'm not starting the tractor to measure movement.

Last summer (without the quick hitch) it lifted fine but you definitely knew it was there.
This summer (4.5" further back) it struggles to lift it to full height and the front end is very light.
This puts the COG of my 925 lb lift at 49" behind my lift arm/lower link connection.
There was a couple times when it balled up with wet gravel that I could only lift it 4 or 5" before I ran out of hydraulics.
With added weight to keep the front down, it would lift to full height but it didn't like it so I am fairly comfortable this is right at my max lift (in my current configuration).

I readily accept that while this is what I have, It would only translate to other machines with exactly the same setup as I have, not a generic fits-all for machines with a rated 400 lbs @ 24" lift

Sodo, were you looking to just get the weight off the ground or lifted to full height? There would have been easily another couple hundred lbs of wet gravel when it barely lifted.

 

[Sodo]

Glad someone's still interested in this. I never did get a good feel for the capacities.
Here's what i had in mind, but adjusted a little to the knowledge expressed by many members.

May need further adjustment, but per the POST TITLE, plz "keep it simple" I think the only way to keep it simple is to limit to lift forks (which I don't have).

Post:

1) Tractor model and the mfrs capacity rating at 24" behind 3-pt
2) Put a pallet on the LIFT FORKS (only) and keep adding weight (at the Center of Gravity CG) until it can no longer move the load upward.
3) Post the weight that stalled it.
4) Post the measured "distance" from 3-pt to the CG of the load
5) Post the weight of your pallet forks attachment

NOTES:

a) Top link length changes leverage. If you can choose a length that lifts mostly "level", do that.
b) Just go up and down a couple inches at mid stroke only
c) Choose a weight that's "symmetrical' enough that it's center of gravity is at its center
d) consider keeping the data specifically to "3-pt pallet forks"
e) put some weight in the bucket, if the front wheels lift the data is not usable

 

[gladehound]

Specifications beyond the eyes are only meaningful if the geometry is specified with the spec. and it usually isn't. You can modify this geometry and achieve a perfect parallelogram. If you do this the lift at the eyes will equal the lift at any point beyond the eyes until the front lifts or something breaks. I suggest you add more control for geometry in your request above. For example, the weight a given tractor can lift will change depending on which 3pt fork is used due to differing distances between the bottom pins and the top link.