Forks Math formula for lift capacity for forks

[shale59]

Looking for a math formula that I can use for my customers to figure out what lift capacity of the tractor needs to be to lift different size bales, particulary round bales taking in to account the cantaliever effect. I want to make sure I am selling them the correct tractor for their need if themain use is lifting round bales for feeding livestock. I am new to selling tractors so I do not want to mislead anyone. I know the breakout point and at full height capacity with the bucket. I would appreciate any short cuts. Thanks in advance.

 

[RedNeckRacin]

I think your best bet is to add a margin of safety. Most of the manufactures post a 24" from hinge point capacity. subtract the weight of the bale spear and then add a good margin for the bales. If you tried to sell my a 1500lb capacity loader to move 1450lb round bales, I'd have a real hard time trying not to laugh. You can estimate bale weights but no one really knows what every bale weighs. Throw in some moisture or some ice and snow and the math really doesn't matter at that point especially if frozen to the ground. They could also change species of grass or the baler could change and all bets are off again. I'd really be looking at a 25% margin of safety to just spit ball it.

if you really want to complicate things, throw in some uneven terrain or even some good tractor ruts.

 

[roadhunter]

My little CT-445 Bobcat/Kioti would barely lift a small dry round bale, and that was with a heavy counterweight. For comfortably handling round bales with a Kioti I suspect you would need to be in the 60+ HP range with a counterweight.

 

[shale59]

Thank you that will give me a starting point. And I understand uneven ground and terrain as I live in the mountains. I do always over gauge the weight of the bales as I have moved them and understand the difference. Kioti states the full height lift capacity at the pin as they realize they can'tkknow what someone is going to put on the front or what implement they will use. I have sold Dodge diesel trucks for years and could often not get people to understand the truck may pull it but try stopping may be something else. Again thanks for the response

 

[shale59]

Thanks for then insight. I do always tell my customers to attach a heavy implement on the 3-point to counter weight. I always take the chassis weight into account also.

 

[RNeumann]

So without the full engineering and variables the starting point would be to take the lifting capacity at the pivot points and then the lifting capacity at 24". Once you understand this ratio you can extrapolate (roughly) how much weight the FEL can lift at a given distance.
With a chart made say in 1' increments it would look something like this-

PP- 3000#
12"- 2500#
24"- 2000#
Etc

Then take the bale and divide the total weight per foot. With this info you would need to place a percentage of total lift based on the chart.

From their you can get an idea of what it will lift. This is rough and the variables are many. Good luck and hopefully someone has better info.

 

[shale59]

Thanks that helps immensely!

 

[roadhunter]

The kicker about a bale is it's center is likely more than 24" out in some cases. So between losing more capacity being out at 28" or so and having a safety factor so the rear tires are actually on the ground you probably need to figure somewhere around 75% of rated capacity at 24" after you back out the QA and forks.

So if it was rated for 3,000 pounds at 24" and you back out a 200# QA plate and a set of say 400# forks to get to 2400# then multiply that x.75 it would put the capacity for bales at around 1,800 pounds.

One thing I've noticed is the ratings for tractors are best case scenario on level ground with a ballast. Driving downhill, or on any kind of slide slope, even letting a front tire go in a dip can cause the tractor to become unstable from my experience.

Skid steers are different as they have a rated capacity which is much much less than the tipping capacity. Tractors almost seem to use tipping capacity as rated capacity.

 

[shale59]

Thank you. Yes you are correct in the assumption most tractor manufactures use on not real world numbers. Kioti rates theirs 2 ways breakout lift from ground and at full height of bucket at piviot points which means if you can roll your bucket back you can actually lift that weight. But that is why I want to be able to show my customers what they can in reality lift with a quick attach implement.

 

[Turbys_1700]

New Holland rates my 621 TL at 3550# to full height at the pins and 2200# at 800 mm. 800 mm is equivalent to 31.5" and should be at the the bucket edge. That is approximately 62% of rated capacity at full height of the pins. I would think that 60% to 65% of rated capacity at full height would be a close estimate.