3PT Life Capacity Question

[ericrm2005]

This is likely going to sound like a stupid question, but I am going to ask it anyways. When a tractor says the 3pt lift capacity is a certain weight at 24 inches behind the lift does that mean it can lift any implement within that weight or do I have to deduct weight since the implement hangs well beyond 24 inches behind the link. For example the tractor I am looking at says 2200 lbs capacity rear lift, and in looking at disk for it, it says 2100 lbs. Not sure if this would handle it.

By the way, im pretty sure im going to be purchasing a john deere 5065E. I have had smaller compacts my whole childhood and will soon be out on my own and getting a larger tractor for work on my property. One thing ive noticed in my search for this tractor is it seems that in this range all of the impelements are either too large or too small. Any insight on this and any input on the tractor itself?

 

[RoyJackson]

This is likely going to sound like a stupid question, but I am going to ask it anyways. When a tractor says the 3pt lift capacity is a certain weight at 24 inches behind the lift does that mean it can lift any implement within that weight or do I have to deduct weight since the implement hangs well beyond 24 inches behind the link. For example the tractor I am looking at says 2200 lbs capacity rear lift, and in looking at disk for it, it says 2100 lbs. Not sure if this would handle it.

That's an interesting question and the rating is open to interpretation.
I'm sure the 3PH rating is either calculated (no actual physical testing) or tested using specified weights mounted on a fixture 24" aft. You'd have to ask the manufacturer for clarification of the testing methods though.
For many implements (ballast box, tiller or flail mower), the 24" would be applicable due to their short length.
For implements with more length (rotary cutters come to mind):
But don't forget the top link which provides a stabilizing of the implement on the draft links (but does not add any lifting energy). The top link would focus (for lack of a better term) the implement weight close in to the 3PH.
Then, of course, one would factor in the effect of front ballast.

So, that 5065e should lift the 2100 lb disk with no problem...but it's likely you'll want front ballast.

Make sense? Or has my first beer of the morning done my "talking" for me?

 

[Chaddo]

Ericrm2005 welcome to the forum

 

[ericrm2005]

No that definately makes sense. Id imagine the top link would center most of the weight closer to the back of the tractor, and then it would be more of an issue of ballast rather than actually how much weight the hitch is lifting.

Its just very hard to find implements for a tractor of this size. It has me thinking I might need a larger tractor for my field work and smaller tractor for my other chores. Hopefully that isnt the case, as I certainly cant afford two tractors, and would much rather have one at this point.

Thanks for the response.

 

[MaJYk]

You can think of it in terms of putting a cheater pipe on a wrench... The farther away from the nut, the less force it takes to get equal torque. If you reverse that, thinking of the point where the lower lift arms meet as the "nut". The nut can only supply a specified amount of torque to provide the lifting power. The farther away the center of mass of the implement is from the tractor, the lower actual weight it will lift. Also, the farther away the same weight is, the more front ballast needed to maintain equal front ground pressure.
How Deere figures the 2200#, and what factor of safety they use, I have no idea. But I cannot see how a 5k series tractor would not comfortably handle a 2100# mounted disc. I use our 5525 (and 5400 before that) to move a 25' mounted field cultivator a couple times a year for mowing. It can't do much with it, but will pick it up enough to move out of the way to mow.

 

[Transit]

The force generated by the power pack has a constant maximum value; the rest is leverage and the way the levers are connected. The manufacture rates the 3pt hitch at a given arm length as so many pounds of lift. [24 inches] if the load is attached beyond 24 inches the lift capacity will be less. It is not a matter of simply subtracting X pounds, it is a matter of the ratio of the lengths of the levers. Find yourself a senior high school student to calculate the load for you.

Levers- EnchantedLearning.com

Levers

 

[SPYDERLK]

The force generated by the power pack has a constant maximum value; the rest is leverage and the way the levers are connected. The manufacture rates the 3pt hitch at a given arm length as so many pounds of lift. [24 inches] if the load is attached beyond 24 inches the lift capacity will be less. It is not a matter of simply subtracting X pounds, it is a matter of the ratio of the lengths of the levers. Find yourself a senior high school student to calculate the load for you.

Levers- EnchantedLearning.com

Levers

Actually it is not simple leverage. You are going to have to find someone that recognizes a parallelogram linkage and understands it.
larry

 

[J_J]

Deleted . Substituted this


http://www.tractorbynet.com/forums/kubota-owning-operating/6983-3pt-weight-capacity.html#post71506

 

[RoyJackson]

That is your max weight at the lift pins. Any more weight than that, might give you trouble, or not lift it at all, or cause the relief to go off.

Deere rates capacity 24" aft of the hitch pins, J_J

 

[MaJYk]

The force generated by the power pack has a constant maximum value; the rest is leverage and the way the levers are connected. The manufacture rates the 3pt hitch at a given arm length as so many pounds of lift. [24 inches] if the load is attached beyond 24 inches the lift capacity will be less. It is not a matter of simply subtracting X pounds, it is a matter of the ratio of the lengths of the levers. Find yourself a senior high school student to calculate the load for you.

Levers- EnchantedLearning.com

Levers

Were you just trying to help or trying to make yourself feel superior?
When you feel you truly have helpful information to ease somebody's dilemma, they might actually use the pertinent part of your post if u weren't such an ••• about it.

 

[J_J]

Deere rates capacity 24" aft of the hitch pins, J_J

Sometimes Kubota quotes both weight limits.

 

[Transit]

From the Ops question he knows little about calculating leverage forces, however he has a gut feeling that as the lever arm is longer the lifting capacity is reduced.

What do we know about the problem?

The hitch can lift 2,200 # on a lever arm of 24 inches, and nothing more. We have no information about the dimensions of the parallelogram.

We know nothing about how long of a lever arm the OP intends to use.

While technically correct, there are too many unknowns to solve the problem using a parallelogram.

I chose the best fit, a class 3 levers that will give an estimate of the load that can be lifted.

With all the chit-chat flying about we have no response from ericrm2005 if my solution is acceptable to him.

 

[SPYDERLK]

From the Ops question he knows little about calculating leverage forces, however he has a gut feeling that as the lever arm is longer the lifting capacity is reduced.

What do we know about the problem?

The hitch can lift 2,200 # on a lever arm of 24 inches, and nothing more. We have no information about the dimensions of the parallelogram.

We know nothing about how long of a lever arm the OP intends to use.

While technically correct, there are too many unknowns to solve the problem using a parallelogram.

I chose the best fit, a class 3 levers that will give an estimate of the load that can be lifted.

With all the chit-chat flying about we have no response from ericrm2005 if my solution is acceptable to him.

The levers end at the eyes. The eyes cause articulation of a "4bar linkage". From this articulation point a pseudo //ogram governs the drop in available lift force. If the //ogram were perfect there would be no lessening of force with distance beyond the eyes. Trying to force this system analysis using simple leverage will yield a significant underestimate of lift ability.
larry

 

[LD1]

The levers end at the eyes. The eyes cause articulation of a "4bar linkage". From this articulation point a pseudo //ogram governs the drop in available lift force. If the //ogram were perfect there would be no lessening of force with distance beyond the eyes. Trying to force this system analysis using simple leverage will yield a significant underestimate of lift ability.
larry

Larry is correct here.

Hey Larry, Have we been down this road before?:laughing:

A perfect parallelogram would result in NO loss of lift capacity. Keeping the front end down is another thing alltogether. A perfect //ogram will make the implemet raise perfectly level. In order to achieve this, to toplink HAS to be the same length and on the same angle as the lower links.

In reality, this is usually not the case. The TL is usually a little shorter and on a downward angle toward the tractor (gets closer to the lower links the closer you get to the tractor).

This will result in a slight dedcution. On the other hand, if the TL were longer and on an uphill angle (gets closer to the lower links as you move toward the implement), this causes the back of the implement to raise LESS than the front. This would result in a slight increase.

If your tractor has multiple places to mount the TL, the highest point will get the most lift. The lowest will cause the tail of the implement to raise higher and give a lower capacity.

TO the OP: What tractor are you working with that has a 2100lb capacity.

According to deeres website, the 5065e that you say you plan on buying lists TWO capacities @ 24". One is ~3100lbs, the other ~3500lbs. Either way should be more than enough for your 2200lb disk.

 

[ericrm2005]

thanks for all the posts, tractordata.com has it listed at 2200lbs. that must not be correct. 3500 would eliminate the concerns i had

 

[jenkinsph]

thanks for all the posts, tractordata.com has it listed at 2200lbs. that must not be correct. 3500 would eliminate the concerns i had

I was just fixing to check the specs myself as the 2200lb capacity seemed very low to me. The 4x20 series are about 2500 lbs 24" out from link ends.

 

[ericrm2005]

I was just fixing to check the specs myself as the 2200lb capacity seemed very low to me. The 4x20 series are about 2500 lbs 24" out from link ends.

tractordata.com as well as some others online list it at 2200. I did think that seemed low, but upon checking the deere sight I see that its above 3,000. I guess for future reference, I will not use any spects posted on that site.

 

[jenkinsph]

The smaller 4105 model is rated at 2200lbs @24" behind link ends IIRC.

Tractor Data is usually correct in their defense and if notified will correct this error. I would still use them for a reference. When and if serious about buying a specific Deere or other brand I would certainly check the factory specs and make sure things like rear hydraulic outlets are available with my dealer.

 

[ericrm2005]

I agree, I will be checking with the dealers and getting all the specs from them when I get down the road. I am just in the very early stages right now and will be getting into a dealer most likely mid summer to do some serious shopping. I do think I am pretty well set on the 5065e. I am pretty well set on John Deere. We are a John Deere family. They have always been good to us, so id like to continue the tradition. The tractor also seems to be affordable and up to the tasks I will have at hand. I am planning on keeping the machine a while, and looking not only at my needs today but also my future needs. I believe this tractor would give me quite a few years to grow until I had to buy a larger machine. Best of all worlds for me.