Tractor Sizing How Much Can A Sub Compact Tractor lift?

[LD1]

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!

The MFG rates them with sufficient ballast to get the full power from the loader. Usually ballast amount is listed in the loader specs, allthough I am not sure kubota lists it. But I know I have seen that listed on kiotis and mahindras spec.

So to answer your question, YES your loader is limited by the weight of the machine. BUT, the ratings are done ballasted so that weight dont apply. Without something on the back and loaded tires, I think mine would pull the rear tires with 300# in the bucket. Been alont time since I been without fluid in the tires. And even with fluid in the tires and nothing on the back, Best I can get to is ~1500psi on my gauge. Not even close to the rated 2350psi or my setting of 2650psi

 

[LD1]

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.

If I remember when I am down at the shop today, I'll snap a picture of the curl power graph in my manual and post later today.

 

[k0ua]

Yeah, it all kinda boils down to this: If the tractor whatever its size is doing the job as far as lifting, pushing and pulling the things you need lifted, pushed, and pulled then keep it. If it is not doing the job most of the time, then swap it in and get a bigger one.

 

[gladehound]

Yeah, it all kinda boils down to this: If the tractor whatever its size is doing the job as far as lifting, pushing and pulling the things you need lifted, pushed, and pulled then keep it. If it is not doing the job most of the time, then swap it in and get a bigger one.

That's one way to look at it. But I'd rather get it right the first time.

 

[TJP89]

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.

It's a huge amount of work, I haven't done it, but have done things like it in the past, and the engineers who do that for a living deserve every penny they are paid.

Also, in addition to the theoretical hydraulic capacities of the loader, the physical limitations of the loader and tractor materials have to be accounted for, figuring in the geometric strengths and weaknesses. That I have never done, because that math is downright scary.

Technically it can be done, but there are a ton of factors that have to be considered.

 

[gladehound]

The MFG rates them with sufficient ballast to get the full power from the loader. Usually ballast amount is listed in the loader specs, allthough I am not sure kubota lists it. But I know I have seen that listed on kiotis and mahindras spec.

So to answer your question, YES your loader is limited by the weight of the machine. BUT, the ratings are done ballasted so that weight dont apply. Without something on the back and loaded tires, I think mine would pull the rear tires with 300# in the bucket. Been alont time since I been without fluid in the tires. And even with fluid in the tires and nothing on the back, Best I can get to is ~1500psi on my gauge. Not even close to the rated 2350psi or my setting of 2650psi

I think you're right. My loader manual specifies 1,047 pounds on the 3pt.

 

[TJP89]

Yeah, it all kinda boils down to this: If the tractor whatever its size is doing the job as far as lifting, pushing and pulling the things you need lifted, pushed, and pulled then keep it. If it is not doing the job most of the time, then swap it in and get a bigger one.

That's the way I look at it. Numbers mean nothing until compared and used in the real world. In fact, numbers are just a way of comparing real life facts to one another, they mean nothing in themselves. I know I need this number to do something. If the tractor has that number, great, if not, moving on.

 

[davesl708]

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".

I did not take it as a put down on SCUTS. Just a comparison. To muddy the water more I used to have a JD 214. 18hp and 36" mower. It also had hydraulics for the 36" snow blade and a 36" tiller. Pushing more than 3" of snow was worthless with 2WD. Tiller did fine though as long as the ground was already broke. I think that thing weight all of 250lbs.

 

[LD1]

Here is the curl chart, and the specs.



1 KN is ~224lbs

bucket rollback force cannot be measured at the pins, thus I assume it is at the edge of the bucket. Max at almost 2600#, whereas my max lift (breakout) at the bucket edge (~500mm forward) is only 1858#

Another reason to think breakout is lift only....

Because if it was a combination of lift and curl, how/why would it be less than the rollback force? Max breakout if a combination of functions, would not be less than the curl force.

 

[LD1]

Here is the curl chart, and the specs.

View attachment 447117View attachment 447118

1 KN is ~224lbs

bucket rollback force cannot be measured at the pins, thus I assume it is at the edge of the bucket. Max at almost 2600#, whereas my max lift (breakout) at the bucket edge (~500mm forward) is only 1858#

Another reason to think breakout is lift only....

Because if it was a combination of lift and curl, how/why would it be less than the rollback force? Max breakout if a combination of functions, would not be less than the curl force.