BIGGER loader cylinders.

[Reg]

OK, so if ANYONE ELSE asked about this I would just say "DON'T"

That said, I am running out of lift capacity on my C50-HL.
Supposedly it has 2540 lbs capacity and given that I just had a 40 cu ft trunk of sappy sappy pine on it (plus the grapple) I think it is working as designed and built.

But, there is always a BUTT.
That barely got off the ground and I wouldn't have been able to load it onto a trailer, I put it down and cut it before dumping.

According to the manual it has 55mm internal bore cylinders (the C50 has 50mm cylinders).
So, hydraulics being what it is - a 10% increase in diameter should offer a 21% increase in available force (at the cylinder, ignoring loader geometry for the moment).
I am thinking 60mm might give me what I want, it comes out to ~19%.
65mm would give ~39.7% and I think other things could fall victim to what I might then be tempted to lift (&carry).
There may be some inch sizes that would work, but I think I want to AVOID going over 25% increase.

Basic question; Has anyone here actually DONE an up-size on this loader ?
If so, how did it work out ?

I am well aware that there may be other limitations, e.g. stresses on other parts, stability when lifting (and CARRYING) larger loads than designed for.
With the pine trunk in the grapple I had the hoe on the back at the time and my R4s are loaded with RimGuard - so it wasn't about to do a front wheel stand (a "stoppie").

BTW, Surplus center cylinders in this sort of size seem to be $250 - $280, so it is likely a $500 < project.

 

[oldpilgrim]

bigger cyls mean slower operation. Are you ready to slow down everyday operations for the few times you actually need the lift?

I'd be worried about the front end under a 25% load increase.

 

[oldnslo]

If you Change the lift cylinder sizes to obtain more lift will the curl cylinders handle the extra load or will they now be the next "weak" link.

 

[BHD]

if one can get closer to the tractor it should lift it easier, depending on what you had for an attachment the further from the pivot point the more weight it appears, to the tractor, less mechanical advantage,

chain off the front of the loader, not the bucket, if forks are on a bucket, use forks with out a bucket, just the few inches the bucket is deep can make one lose a lot of lift capacity, (check psi on tractor and see if the tractor is developing the correct pressure for the hydraulics,

bigger cylinder, my mean broken front axle, bent loader arms, and a whole bunch of other expensive and fun problems,

you most likely did the best cut the tree smaller,

 

[Midniteoyl]

If your pump can handle it, you could also adjust your psi up 100-150.

 

[Reg]

Slower lift COULD be a plus, especially with heavy loads.
Fast and jerky vs slow and smooth.

Bucket cylinders seem to have better mechanical advantage than lift cylinders do anyway, as witnessed by the breakout force being about 900 lbs greater than the lift force.
Closer in ? Well, sure but I am using a grapple and while it is true that it can lift a little more in the vertical "grab it" position I don't like to raise it very far before rolling back into a carrying position - and rolling back does extend the load away from the pivot.

Not saying I haven't lifted, then rolled back, but it never feels right to rely solely on the grapple's grip.
I could and SHOULD clear the site a bit more before taking out a ton or so; saws, fuel cans. etc. - - but if you drop something that big it will always roll to where it can do the most injury/damage anyway

I agree with the whole "upgrade this and you will likely break that" argument, but Kukje tractors and Humpolec loaders are tough and I am confident that there is AT LEAST another 30% capacity in the "everything else".
Again, 20% to 25% should keep me (or any future owners) within what the tractor can take.

 

[Luke'sScreenName]

Have you already increased your relief pressure above spec?

 

[Reg]

Have you already increased your relief pressure above spec?

I have not.
I have taken that it can lift a ton of wood plus the grapple as fair evidence that it is at least up to spec.

I would rather go for cylinders with say 19 % more cross sectional area than put an equivalent 19% more pressure through the whole hydraulics system - although as I say that I realize that there is probably more margin in all the hoses and valves than in a lot of the mechanical bits

Anyway, I was looking more for someone who has actually DONE a cylinder up size and their results.

 

[Reg]

Having "slept on it" I think I will try turning up the relief pressure.
a) I don't have a suitable pressure gauge, but buying one is a good idea anyway for trouble shooting and they MUST be cheaper than bigger cylinders.
b) This is reversible.
c) A little more BITE in the grapple would be reassuring.
d) A little more FORCE would be nice ...well, just about EVERYWHERE

 

[LD1]

I think you have a good plan for step 1 in getting a gauge.

But a couple of notes.

1st, about you assuming the curl is stronger based on higher breakout force. It has been discussed (and even argued about) before on TBN, but breakout force is not curl power. Rather it is your lift power, but at ground level.

If you are familiar with hydraulics, you know that the cylinders angle changes the force it can lift with. Well, a loader travels in an arc as it raises, thus changing the cylinder angle. The result is the higher you lift something, the lower the capacity. Or in other words, the lower you the height, the more power you have. Thus the 900# difference between breakout (ground level lift) and lift to max height.

Second note, Increasing cylinder bore area by 19% will increase your lifting capacity by a good bit more than 19%. How much more all depends on the geometry of the loader and cylinders and I have no idea what they are for your loader, But here is a rough example:

Lets say you are operating at 2500psi and that gets you 2500# of lift capacity. Well, the loader frame + bucket or grapple arent lifted for free. That takes power just the same as a load in the grapple would. (again, how much so depends on the geometry). So you have to figure the true lifting force the cylinders can generate on their given angle, and given distance (leverage) from lift and pivot points......THEN subtract the dead weight of the loader and you arrive at your 2500# lift spec. Increasing cylinder bore area by 19% increases their lifting power by 19%, but the dead weight of the loader frame/bucket remains the same. So the net result is more than 19% increase in bucket capacity.

Hope you can follow that. Here is a simplistic example.:
current cylinders can push on the loader frame with an upward force of 3500#. But it takes 1000# to lift it empty. Result is 2500# avaliable for lifting a load.

Increase cylinder power by 19%.....3500 x 1.19 = 4165#. Now take off the same 1000# required to lift the frame/bucket and the new lifting capacity is 3165#. Which is a 26.6% increase in bucket capacity with a simple 19% cylinder size increase.


Now along those same lines, increasing pressure has the same result. Since the dead weight stays the same. If you increase pressure by 19%, you are increasing real lift capacity by a fair bit more than that.

With your loader rated at 2500#, and probably a 2500psi spec, one would tend to think it is simple in that for each PSI you increase, you can lift an additional pound. But remember, the weight of the loader. With that 2500PSI you are really lifting something probably around 3500# with that dead weight. So, 3500/2500 is more like 1.4# for every PSI increase. So a 200psi bump in pressure is probably gonna net closer to 300# of extra lift capacity as opposed to 200#