Tractor Sizing How Much Can A Sub Compact Tractor lift?

[k0ua]

Have no idea why every single post I have made lately doubles. IF I click "leave this page"...double post. IF I click "stay on this page"...double post.

Eh...good way to boost the post count I guess.

The double post thing seems to have returned with a vengence in the last few days. I go back and delete one of the posts as soon as it happens. press edit post, then press the delete button , delete message, delete and it goes away.

 

[gladehound]

Kubota, kioti, and mahindra dont disclose curl power. But kubota does have it in the manual

I was surprised to see you mention that Kioti doesn't list curl power. I checked the Kioti web site and I don't see roll back listed for my loader but it used to be there! It also used to be there for the loaders for the DK45S and the DK55 for sure and probably for the larger tractors as well. I don't recall ever seeing it for the CK series.

I have an old brochure here for my KL402 loader and bucket rollback is listed as 2,990 pounds @ 19.7 inches (500mm).

Ah - just found an old brochure for the DK45S and DK 55

DK45S bucket rollback force at ground line 3,555 pounds (distance looks to be 25.2" but a little unclear")
DK55 bucket rollback force at ground line 4,580 pounds (distance looks to be 25.2" but a little unclear)

 

[LD1]

I could have swore it used to be there on kubotas site as well, but could have been mistaken.

While having alot of curl power is nice, I dont think it is as important of a spec as lift, and often not even mentioned when comparing.

And it es even more dynamic than simple loader lift, that gradually falls off as it is raised. If you drew a graph with force for the Y axis and 0-whatever degrees is the max range of motion for curl being the x axis, that chart would be an arc. Starting small at full dump then increasing til about mid range (usually a little below flat-bottom at ground level), then it will fall back off nearing full curl.

And to even further muddy the waters....

Curl power at bucket edge is usually always stronger than lift. How far in front of the bucket the load is placed for either curl or lift is a straight line.

Curl power starts off greater but falls off faster.

IE: Just throwing numbers out, if you can curl 3k at bucket edge and lift 2k at bucket edge.....
At 24" father out (pallet center), it may be something like 2k curl (33% lost) and 1500# lift (25% lost)
Out 4', it may be 1k all around. Beyond that, lift is stronger.

This happened when I was setting trusses at my old place. 15' boom on the bucket. Couldnt curl back very far at all. Trusses were ~150#. Had to have someone "help" it out. But had no issues at all lifting.

 

[davesl708]

I would argue that a SCUT is not an overgrown garden tractor because it doesn't necessarily have more ground clearance. In fact, compared to the garden tractors I've used, modern SCUTs tend to have much less ground clearance. As such, their design seems to lend them to lawn use more than garden use.

The article also states that a SCUT is similar in dimensions to a garden tractor. Therefore, it is not overgrown grown compared to a garden tractor. Perhaps it would be better to label it an over featured garden tractor. But then there is the ground clearance issue.

Given the design and primary use of a SCUT, it seems to be the top end category of premium lawn tractors. As a premium lawn tractor it has many capabilities that lesser lawn tractors don't have (cat 1 3pt. loader / backhoe availability). CUTs are typically not optimized for yard mowing as a primary task. However, there are some exceptions.

The only reason that I really am not a SCUT fan, is that they seem to be priced on the high side compared to larger tractors. So I struggle with the value equation. But for those who want the versatility and either need the small size to access work areas or have limited space to store equipment I can see how they make a ton of sense.

Well. My JD was 467lbs had a 22hp gas engine and very little ground clearance. It could mow and pull my 25 gal. tank sprayer.

My BX is 1300lbs has 22hp diesel more ground clearance and can operate a FEL, 60" MMM, 4ft tiller, can pull a plow, harrow, pull the sprayer and rear blade. Has cleared over 100 trees and brush <2" and moved dozens of cords of wood.
Cleared 200' of drive of over 10" of snow.

Definitely a different class than the garden tractor I had.

 

[jenkinsph]

I always thought that the break out force assumes curling the bucket where the rear of the bucket on the ground provides a fulcrum point. How much force is applied to the bucket lip would vary with the length of the bucket used. Same is true for a backhoe bucket rolling against itself. The lever length is much shorter and allows you to "pry up" the dirt or rock breaking it free.

I don't have a clue what the manufacturers are using to determine this so I keep reading and watching this thread for enlightenment. At least this thread is good for something.

 

[gladehound]

Well. My JD was 467lbs had a 22hp gas engine and very little ground clearance. It could mow and pull my 25 gal. tank sprayer.

My BX is 1300lbs has 22hp diesel more ground clearance and can operate a FEL, 60" MMM, 4ft tiller, can pull a plow, harrow, pull the sprayer and rear blade. Has cleared over 100 trees and brush <2" and moved dozens of cords of wood.
Cleared 200' of drive of over 10" of snow.

Definitely a different class than the garden tractor I had.

Completely agree that SCUTs are in a very different class than modern Garden tractors. And not trying to put SCUTs down at all. They are very capable small tractors.

The garden tractor / SCUT comparison gets muddy when comparing to garden tractors from a few decades ago that were as heavy as a modern SCUT but lacked some of the features, capabilities. Some of those old Bolens garden tractors were beasts! You have to understand that making this comparison is in no way putting down the SCUT. A wide range of garden tractors have been sold over the years to it depends on what pops into your mind when someone says "garden tractor".

 

[jenkinsph]

Well. My JD was 467lbs had a 22hp gas engine and very little ground clearance. It could mow and pull my 25 gal. tank sprayer.

My BX is 1300lbs has 22hp diesel more ground clearance and can operate a FEL, 60" MMM, 4ft tiller, can pull a plow, harrow, pull the sprayer and rear blade. Has cleared over 100 trees and brush <2" and moved dozens of cords of wood.
Cleared 200' of drive of over 10" of snow.

Definitely a different class than the garden tractor I had.

What model Deere are you referencing? At 467 lbs. this sounds like a lawn tractor not a garden tractor. My x749 is 1200 lbs. plus, so close to the weight of the bx. FWIW I think the BX line are great machines, so not knocking them in any way.

 

[gladehound]

I always thought that the break out force assumes curling the bucket where the rear of the bucket on the ground provides a fulcrum point. How much force is applied to the bucket lip would vary with the length of the bucket used. Same is true for a backhoe bucket rolling against itself. The lever length is much shorter and allows you to "pry up" the dirt or rock breaking it free.

I don't have a clue what the manufacturers are using to determine this so I keep reading and watching this thread for enlightenment. At least this thread is good for something.

And I think you are right as what you describe is method #5 of the published standard. But manufactures have 3 different methods to choose from as listed by the published standard. The method you describe seems to be more commonly used for construction equipment whereas method #6 seems more common for CUTs.

From SAE J732 describing breakout force:

1. Loader on hard surface, transmission in neutral
2. All brakes released
3. Unit at standard operating weight, rear of loader not tied down
4. Bottom of cutting edge parallel to ground, no more than .75" above the ground
5. If tilt circuit is used, bucket hinge pin must be specified as pivot point, and lift arms should be blocked under bucked hinge pin to minimize linkage movement.
6. If lift circuit is used, pivot point should be specified as lift arm hinge pin, and front axle should be blocked to minimize tire deflection.
7. If both circuits are used, the dominating pivot point must be specified.
8. If the circuit causes the rear of the machine to leave the ground, the force required to lift the rear of the machine is the breakout force.

 

[gladehound]

Looking at #8 makes me wonder if my ~3800 is limited by the capability of the loader or by the weight of the tractor. I've lifted the rear with filled tires, cage and blade on the back!

 

[gladehound]

I could have swore it used to be there on kubotas site as well, but could have been mistaken.

While having alot of curl power is nice, I dont think it is as important of a spec as lift, and often not even mentioned when comparing.

And it es even more dynamic than simple loader lift, that gradually falls off as it is raised. If you drew a graph with force for the Y axis and 0-whatever degrees is the max range of motion for curl being the x axis, that chart would be an arc. Starting small at full dump then increasing til about mid range (usually a little below flat-bottom at ground level), then it will fall back off nearing full curl.

And to even further muddy the waters....

Curl power at bucket edge is usually always stronger than lift. How far in front of the bucket the load is placed for either curl or lift is a straight line.

Curl power starts off greater but falls off faster.

IE: Just throwing numbers out, if you can curl 3k at bucket edge and lift 2k at bucket edge.....
At 24" father out (pallet center), it may be something like 2k curl (33% lost) and 1500# lift (25% lost)
Out 4', it may be 1k all around. Beyond that, lift is stronger.

This happened when I was setting trusses at my old place. 15' boom on the bucket. Couldnt curl back very far at all. Trusses were ~150#. Had to have someone "help" it out. But had no issues at all lifting.

A lot of great points are made in the post above. And this explains why you have to be careful using buckets designed for skid steers. A person may have more curl than lift with the short bucket that came from their CUT manufacturer. Slap a 42" deep skid steer bucket on there and suddenly that curl feels weak.

All this discussion makes me want to calculate all these forces for my tractor based on cylinder surface area, lever lengths, vector forces, and relief pressure... But that sounds like a lot of work.