Here are the ACTUAL Lift Capacities of the RK24 L75 FEL @ Varoius Heights (w/ Graph!)

[snymat68]

I didn't have time for any testing tonight, and the next couple nights I'm busy. Will probably get to it this weekend sometime.
But here's a screenshot of the updated spreadsheet with the theoretical lift capacity calculations.

 

[snymat68]

Still haven't gotten a free minute with good weather to rerun the lift tests. Hopefully I'll get a chance one evening next week if I'm not too busy with work. :crossfingers:

 

[shooterdon]

Interesting thread...I am also an engineer and love my spreadsheets....LOL

It will not surprise me to see your actual values higher than "spec". Too much liability for manufacturers not to build in a degree of safety factor. Below is a JD 1025R moving a load of firewood that should weigh over 1200 lbs. Loader is rated for 955Lbs at the pins. Of course keeping it low helps a lot. In many cases, at least for me, I am not lifting heavy loads to full height.

John Deere 125R Bringing the Firewood In - YouTube

It would be more informative if specs also listed rated load at 20" in front of the pins and 60" high. That would mimic fork and grapple use more realistically.

 

[LD1]

Interesting thread...I am also an engineer and love my spreadsheets....LOL

It will not surprise me to see your actual values higher than "spec". Too much liability for manufacturers not to build in a degree of safety factor. Below is a JD 1025R moving a load of firewood that should weigh over 1200 lbs. Loader is rated for 955Lbs at the pins. Of course keeping it low helps a lot. In many cases, at least for me, I am not lifting heavy loads to full height.

John Deere 125R Bringing the Firewood In - YouTube

It would be more informative if specs also listed rated load at 20" in front of the pins and 60" high. That would mimic fork and grapple use more realistically.

Manufactures don't derate anything or build in any safety factor.

It's a math calculation. Geometry + hydraulics. They simply publish the results of the equation. No magic, mystery, underrate, overrate, etc as many always believe.

And alot of mfg's do five ratings for various heights and at various distances forward of the pins. Right, wrong, or indifferent....everyone has seemed to settle in on the capacity at the pins to Max height. It's good for comparison

 

[coastie15078]

There is a video on the Rk24 lifting gravel and how he calculated lift. I will say this, I am a common sense kind of guy, I would never load my bucket where I felt I would tip even with my backhoe on for ballast. I think, and I could be wrong, but the heaviest thing one would or could ever put in his / her bucket would be concrete. Not that I would use my tractor to pour concrete. I stick with mulch and top soil, and the occasional tree branches / logs. I would love to to get a load of cow manure for the garden. Other then that, snow is the other thing that would find its way into my bucket.

 

[snymat68]

Sorry for not getting back to retesting this yet. I've gotten busy with actually using the tractor for useful tasks. BUT HERE'S MY NEW PLAN for rerunning the test.

I'll be renting a roll off dumpster sometime in May to get rid of a bunch of yard debris, etc. The end of the dumpster hinges open and I'll be able to back the tractor in before I put any junk in there. I can run a chain around the dumpster wheels and up around the floor lip at the open end of the dumpster. This will give me a good anchor point and a nice, level, flat surface to perform the tests on. It will make it easy to reposition the tractor between each test to keep the chain perfectly vertical. I'll probably even use a level or plumb bob to make sure everything is plumb for each test.

So until then, I won't be posting any updates on this thread. Once I have new (hopefully more accurate) results, I'll be sure to post them up. Stay tuned!

 

[snymat68]

Okay. I FINALLY got a chance to rerun the tests this weekend. :cool2:

Let me tell you what, WOW does having everything level, square, and plumb make a difference in the accuracy of the readings! As you can see in the pictures, this time around I performed the test using a 20yd dumpster I rented for some cleanup around the property. Before I started, I blocked up the dumpster to make sure it was level. For all my tests, I made sure the bucket was level, and the chain was vertical. I think this was the biggest source of error the first time I ran the test.

One other difference with this test, was that I ran the chain over the cutting edge of the bucket, not down the back near the pivot pin, as I had done in my first test. Because of this, the readings are reduced from the first test, but I feel that it gives a more useful, realistic set of data. However, the height measurements still reflect the height from the ground (dumpster floor) to the center of the pivot pin.

This time around, I also took a LOT more readings. Every inch, instead of every 3 inches. Basically, every link of the chain. It took a couple hours to run the test and collect all the data, but I think it was worth it, and I had fun doing it. You can see by the updated graph and readings, that these results seem to be a lot more in line with the manufacturer ratings and so forth. Rural King rates the L75 loader at 947lb lift capacity to full height at the pivot pin. I measured 970lb at the cutting edge. So either my numbers are a little off, or they are being slightly conservative. Either way, I feel confident that my data is close and is a good indicator of real-world capabilities.

Derive your own conclusions from the new data, but here are the results.

 

[LD1]

That's a lot more realistic looking graph than tour first test. No doubt alot more accurate too

 

[k0ua]

Which also proves the point I have made many times that reving up the engine results in very little extra lift. As it matters not what the flow rate is that develops the pressure. The only reason that the higher RPM developed a bit more pressure is because as the fluid was escaping over the relief valve, the higher rpm (and higher flow rate) will develope a bit more pressure as the relief valve can't quite keep up with the increased flow so a bit more pressure will develop against the load. Also of course at this increased flow rate now trying to flow over the relief valve much more heat is generated due to the restriction. A lot of people think that higher RPM's which does increase the flow rate will greatly increase the lift capacity but it does not. It does increase the lift speed though.

 

[atsah]

That’s more realistic this time around.. As far as rpm and lifting, it does make a small difference raising the rpm, not a lot but sometimes just the small amount needed.

I had pallet forks on and was attempting to load an old heavy Bush hog onto a flat bed 1 ton and it stopped lifting , I needed another 4 inches, I cranked up rpm’s and I got the 4 inched I needed and got it loaded.