Calculated lost loader lift capacity with quick attach.

[3v0]

I have been reading about this here and else where. Everyone talks about it but I did not see any numbers.

Math was never my strong point so I hope I got this right.

Lets assume a small tractor loader like used on a Kubota BX is 60 in from the rear pivot pin to the bucket. The lift spec is 500 lbs. This gives us 500 * 60 or 30,000 in lbs of torque at the arm pivot. This figure will stay the same.

Now lets extend the lift point by 6 in to 66 in by attaching a quick attach setup. Our new lifting capacity will be 30,000 in lbs / 66 in or 454.5 if we ignore the weight of the adapter. 454/500 is 90%. This also makes sense in that we increased the distance by 10% so the drop in lift capacity is 10% but we should also lift 10% higher.

But add the weight of a 70lb adaptor and we are down to a 385.5 capacity or about 77% of what we started with.

I need to get the tape out tomorrow and see what the actual length of the loader arm is.

 

[Don87]

I have been reading about this here and else where. Everyone talks about it but I did not see any numbers.

Math was never my strong point so I hope I got this right.

Lets assume a small tractor loader like used on a Kubota BX is 60 in from the rear pivot pin to the bucket. The lift spec is 500 lbs. This gives us 500 * 60 or 30,000 in lbs of torque at the arm pivot. This figure will stay the same.

Now lets extend the lift point by 6 in to 66 in by attaching a quick attach setup. Our new lifting capacity will be 30,000 in lbs / 66 in or 454.5 if we ignore the weight of the adapter. 454/500 is 90%. This also makes sense in that we increased the distance by 10% so the drop in lift capacity is 10% but we should also lift 10% higher.

But add the weight of a 70lb adaptor and we are down to a 385.5 capacity or about 77% of what we started with.

I need to get the tape out tomorrow and see what the actual length of the loader arm is.

You are going to be one busy fella for a while.

 

[stuckmotor]

A friend told me that the problem with overloading a FEL was breaking wheel rims and spindles. Has anyone ever done this?

 

[texasjohn]

No
You can chain a FEL down to the ground so it cannot move. One of the following will happen when you lift:

Rear wheels will come off ground...do be careful and don't carry this experiment to its conclusion...a tip over
Hydraulic relief valve will pop...you hear a hissing sound, know tractor is trying to lift, but rear stays on ground because lots of weight back there.

Rims will not break. Spindles will not break
If you have low tire pressure, a loaded bucket, turn sharply, then likely you will roll the tire off of the rim. Carry near max pressure in tire to avoid this mistake.

A friend told me that the problem with overloading a FEL was breaking wheel rims and spindles. Has anyone ever done this?

 

[yanmars]

I have a 33 horse tractor that had the spindles break. They were known for that. I got the larger refit spindles and have not had a problem since.
I would surmise that a heavily loader bucket, traveling at some speed over rough terrrain could cause spindle damage.

 

[stuckmotor]

I took my friend to mean that the breakage occurred over time, due to metal fatigue. He said that the rims broke first. I also took him to mean that after replacing the rims, the spindles broke.

I have a 33 horse tractor that had the spindles break. They were known for that. I got the larger refit spindles and have not had a problem since.
I would surmise that a heavily loader bucket, traveling at some speed over rough terrrain could cause spindle damage.

 

[texasjohn]

Just my opinion, but broken spindles or rims would be either a design specification or manufacturing defect....tractors and FEL's are built to be used with reasonable care but to not be babied.

 

[stuckmotor]

I think you are correct and posted the question to verify this. I recently acquired my first tractor with a loader and am trying to avoid problems.

Just my opinion, but broken spindles or rims would be either a design specification or manufacturing defect....tractors and FEL's are built to be used with reasonable care but to not be babied.

 

[texasjohn]

First problem to avoid is to make sure you have sufficient rear weight to keep tires firmly on ground when carrying max FEL load (so heavy you can only lift FEL load a foot or so). Won't carry this weight often, perhaps, but when it happens you want to avoid tipping forward. Next thing to do is ALWAYS keep FEL load low...again to reduce tipping risk. Do this and you avoid two common newbie operational mistakes. Reading the safety forum will teach you a lot if you haven't already done so.

I think you are correct and posted the question to verify this. I recently acquired my first tractor with a loader and am trying to avoid problems.

 

[3v0]

Just my opinion, but broken spindles or rims would be either a design specification or manufacturing defect....tractors and FEL's are built to be used with reasonable care but to not be babied.

I agree. My thinking is that if you put too much loader on a tractor you might bust it up. But if you use the loader spec'ed for the tractor you should not have a problem.

 

[Gary Fowler]

A friend told me that the problem with overloading a FEL was breaking wheel rims and spindles. Has anyone ever done this?

What breaks a rim is loose lug bolts. You don't actually break a rim, just the bolt holes. In all cases, the lug bolts get loose and allow some flex which eventually fatigues the metal and crack out the rim around the holes. I have seen old tractors with the bolt holes so wallowed out from loose lug bolts that they drilled new holes in attempt to not replace the rim.
CAUTION: Check your lug bolts frequently AND all the bolts that hold the FEL on to the tractor frame. I had an old 1984 Yanmar and the frame bolts would not stay tight. I had a couple that I had to tighten every time I use it. So far none has came loose on my LS with exception of 2 behind the fuel tank and I don't think they were ever tightened to start with as they were difficult to see much less tighten. There was a couple of lug bolts that were a bit loose when I checked them. Every 50 hours would be a good checklist to check ALL the attachment bolts. Check the lug bolts and all attachment as soon as you get the tractor.
As for broken spindles, they do break and not necessarily from loader work. I saw one at a tractor dealer that was broke and the parts guy said the owner only used it to mow with, no loader. Broken spindles would be a design flaw or machining flaw, not necessarily overloading.

 

[jmc]

I think your analysis is correct.

Another consideration in your favor is that (I think) loaders are rated at what they can lift to full height, which is less than what they will lift in the lower part of their range. So you may not be able to lift, say, a large bale to full height, but you might be able still load it onto a truck.

And then there is this. My neighbor wanted me to move some skids of landscaping bricks to the other end of his yard. My L4330 would not lift the entire skid so he started removing the furthest bricks from the tractor, several at a time, until the loader would lift it. In other words, we were very near the capacity of the loader in that position. I had on a medium weight box blade for ballast since space was too tight for a bush-hog back there. Anyway, the tractor felt a little squirrelly once it was moving and once I started into a turn, one of the back wheels started to lift off the ground. So I guess that just because it can be lifted doesn't necessarily mean its a good idea to move it.

 

[SSdoxie]

3v0, You have the right idea regarding calculations but each loader & QA system will vary some. Here are the comparisions of mine with & without QA.

All Measurements are @ 20" front of bucket pivot
Rate Lbs. w/pin on w/QA
Full lift 1108 1032 -6.9%
59" (bucket level w/rear pivot 1264 1168 -7.6%
Boom breakout (lift) @ ground 1644 1571 -4.4%
Bucket roll back @ ground 2194 1989 -9.3%

Average performance loss w/QA -7.1%

 

[stuckmotor]

Thanks to everyone for your advise on the loader. Some of the things you've said can be of immediate benefit. I hope to have this outfit for a long time.

 

[xring100]

You mention a 10% lift height increase that really is not practical as this would only be possible if the curl cylinders are fully retracted putting the 4 bar linkage parallel to the ground. With pallet forks that would put the tips pointing towards outer space. But under level bucket or forks, no increase in height only increase in reach. Everything else sounds good enough for government work.

Dave

 

[puckgrinder85]

I havnt noticed any real decrease in capacity.

 

[xring100]

The easiest but far from most cost effective way to relive these concerns would be to keep your existing tractor and buy another tractor that not only comes with quick detach standard, eliminating the need for these calculations. But also lifts about 3 times your average usage but could lift about anything you could think you'd ever want to lift this does of course have some potential draw backs including $$$, but hey that's why you now have two tractors. No job to big, no job to small.

How i selected my tractor
I really only wanted about a 60 -70hp tractor but wanted close to 3000 lift capacity. So i could lift 3000 plus pallets out of a semi. Could not justify the extra cost of the JD 5M series open station so i bought the larger M8540. I dont worry about not being able to lift things now. If i can't lift something now it didn't need to be moved that bad
i realize that this is not an option for most people. I was at my house 8 years before i could afford mine.

Dave

 

[schmism]

the is such a diffrence in loader capacities of CUT and AG tractors. I have a good friend who has a 75hp case AG tractor. his loader will lift 5200 lbs. why do we know this? because he has used it to lift his empty 20' shipping container with the tare weight printed right on the side. my loader is about 800 lbs and 33hp. figure tripple the size, 99hp the loader capacity isnt anywere close.

Just way to much diffrence in the way light CUT's are designed and built vs heavyer AG tractors

 

[boggen]

i am brain fried at moment so i may be off, do a google search for "first class lever" pages should give examples of second and third class levers as well
and i want to say search for "wiki 4 bar linkage" i think it covers 3 bar linkage, and up to 5 bar linkage.

i think those search should give you multi examples of math.

 

[Baby Grand]

3v0 -Your math is good and problem statement is conceptually accurate.
When you get the tape measurements and recalculate, your lift estimate will be very close.