3-point capacity

[creekbend]

It appears that most of the finer points have already been covered in response to your question. I only wish to suggest this additional concern. If you use the FEL, it would be advisable to have sufficient rear ballast weight to compensate for the weight up front. Just a thought.

 

[LD1]

A kubota M59 FEL would handle the drill easy. And the rear lift and front are about the same on that tractor. You could remove back hoe and use 3 point to pull around with power to spare. No problem.

Yes, the FEL and 3PH capacities are the same on that machine....But that aint no ordianry tractor. That is a Backhoe with a super strong FEL with a 3PH as an option on that machine. But neither the FEL or 3PH have a sufficient enough rating lift the drill with any level of comfort at all.

"Most" farm tractors have about double the capacity out back vs the FEL

 

[ajamison]

You need to know what the total weight of the the drill full of seed is and the approximate loacation of the drill center of gravity(cg). Then you can compare that to the lift capability of the three point. Three point hitches are rated at two locations: at the end of the lift links, and with the load cg located 24 inches aft of the lift links. So you need to pay attention to what number you are qouted. The lift at 24 inches behind the links will always be less then the lift at the links. You can correct one to the other very easily if you can have the correct location for the rating.


If you all ready have the drill, find out what it really weighs when it's full of seed and ready to go. See if the manufacturer can tell you where the cg is located.. The measure the length of the lift link (L) and the distance from the lift links to the drill cg (a). If the spec lift is X pounds at the lift links, and Y is the max weight of the loaded drill, then

X *L = Z*(L+a) or,
Z=(X*L)/(L+a). If Z > Y, the lift will pick up the max weight of loaded drill.

Remember that once you start runing the drill, the load goes down and the drill gets easier to pick up as it's weight decreases.

You lift system has a position control and a relief valve so driving on rough ground with the drill raised may cause some high intertia loads on the lift system and the relif valve will respond by relieving pressure to prevent damage and then the position control will reset the height of the implement. If the ground is really rough, you want to not be highballing in high gear with a heavy weight on the three poinnt, however. Thats' just common sense.
This is the long way around to answering your question.

Jerry, thanks for all the great information. If I follow you calculations correctly, then if (a) is less than 24", then whatever the manufacturer quotes as the rear lift capacity at 24" is the figure I can use in determining whether or not it will pick up the drill. If (a) is greater than 24", than I need to go through your calculations. Is that right?

 

[catskinner]

Find a good used JD 4020, they can handle the weight, plenty of power, and reasonable priced.

 

[LD1]

Jerry, thanks for all the great information. If I follow you calculations correctly, then if (a) is less than 24", then whatever the manufacturer quotes as the rear lift capacity at 24" is the figure I can use in determining whether or not it will pick up the drill. If (a) is greater than 24", than I need to go through your calculations. Is that right?

Not necessarily.

Those "would" be the correct calculations if it were a simple lever.

BUT....the 3PH is a parallelogram linkage. Which means the capacity doesnt diminish that much.

In that "simple lever formula" if you lower links are 24" long, that would be @ 24" behind the ends, you would have 1/2 the rated capacity. And that simply isnt the case. Because "IF" it were a simple lever, that point @ 24" would raise 2x's higher than the "ball ends", and it does NOT because of the parallelogram.

I will note that it is NOT a perfect parallelogram. BUT it is an adjustable parallelogram. Most tractors have several mounting locations for the toplink and the toplink length is also adjustable. Adjusting those two things changes the geometry. The lower hole will cause the implement to rotate about the lower links MORE, causing the point @ 24" back to raise HIGHER than if the top hole were selected. THUS changing the lifting capacity by simply mounting the TL differently. Same goes for its length.

What you should take away from this is that there is no easy way to calculate the lift capacity. All tractors have different geometries to their 3PH's and different ranges in which they can be adjusted. So dont cut yourself that close on capacity. Because if you select one that is right on the bubble, doing something as simple as adjusting the TL to gain a little more height and you might not be able to lift it.

 

[ajamison]

One more question. How much does the weight of the tractor factor into 3 point capacity?

I'm looking at a Kubota M7040 which has the same lift capacity as a MF 375 (I know someone who has a Truax drill attached to the MF 375 and it works well), but the Massey weighs almost 2000 lbs more.

 

[LD1]

One more question. How much does the weight of the tractor factor into 3 point capacity?

I'm looking at a Kubota M7040 which has the same lift capacity as a MF 375 (I know someone who has a Truax drill attached to the MF 375 and it works well), but the Massey weighs almost 2000 lbs more.

Additional weight (depends on how it is distributed) helps keep the front end of the tractor on the ground:thumbsup:

If you are going to be using the 3PH at more than about 50% of its rated capacity, some additional front end weight is almost required. Especially with the newer and lighter tractors of today.

My tractor has a 2000lb capacity @ the pins and a 1500lb capacity @ 24", and with either the 700lb blade or 1000lb bushhog...The front end is TOO light without the FEL to work safely on anything but perfectally level ground.

And not to nit-pick, but I dont know where the rating for the 375 is taken. Tractor data lists it @ 4200lbs. The 7040 is 4200 @ ends and 3300 @ 24". So if the older 375 is 4200 @ 24", that is a pretty big difference?? But again I dont know where it is rated.