Another slope application question

   #1  

Hill HIgh Guy

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Oct 6, 2017
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Purcellville, VA
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None yet
I finally finished construction my house and can now finance a tractor and I'm ready to buy now. I've gone back and forth on what I need. It's 3 acres of former orchard with field grass now that I want to turn in to a decent lawn. The entire property is a pretty steep slope. I've waffled between a 1 series JD (KB BX) all the way up to an L. Sat on and drove everything in between including JD 2025 and Kubota B's. I asked the JD dealer to give me a quote on the new 20205r as I felt that I could spread the rears for stability and the tires were big enough to add weight by filling them. He doesn't have a 2025r in stock and sent me an email yesterday that he took his boss to my property and they agreed with my slope, a 1 series would be the right move as it would be more stable on the slope I have. Now I'm second guessing myself. Could it be that he would rather sell me a 1 series as he's got a bunch of them or is a smaller tractor truly more stable? I've read a ton on here that those little tractors can be tippy and it's harder to add spacers to the rear wheels. I had a Kubota dealer go out to my property and say a B2650 or even an "L" would be the best fit. This is craziness!!

Obviously I'm a newb and I don't want to buy the wrong tractor for 20K+. Thoughts?
 
   #2  

CobyRupert

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Oct 30, 2012
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Washington County, NY
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JD 5075E
I like to quantify.

IMHO, I think the side hill stability of a tractor can be expressed as a fraction: center of gravity height (COG(h)) divided by width (W).
Stability= COG(h)/W.
A smaller value is better.

The hard part is estimating where a model's COG(h) is. And how that COG height is then effected by other additions, such as FEL's, attachments, loaded tires, etc... My gut /guess tells me that most tractor's COG (w/o additions) is a few inches to 1/2 a foot higher than the rear axle.
 
   #3  

smstonypoint

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Oct 13, 2009
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SC (Upstate) & NC (Piedmont)
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NH TN 55, Kubota B2320 & RTV 900, Bad Boy Outlaw ZTR
I like to quantify.......

My gut /guess tells me that most tractor's COG (w/o additions) is a few inches to 1/2 a foot higher than the rear axle.

Not too bad a guess according to Tractor Stability - eXtension.

That article refers to a 2WD tractor. That's a potential source of confusion, at least for me. When ag. engineers talk about 4WD tractors, they are referring to the large articulated ag. tractors with front and rear tires of the same size.


Steve
 
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   #4  

flusher

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Jun 4, 2005
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Sacramento
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Getting old. Sold the ranch. Sold the tractors. Moved back to the city.
I like to quantify.

IMHO, I think the side hill stability of a tractor can be expressed as a fraction: center of gravity height (COG(h)) divided by width (W).
Stability= COG(h)/W.
A smaller value is better.

The hard part is estimating where a model's COG(h) is. And how that COG height is then effected by other additions, such as FEL's, attachments, loaded tires, etc... My gut /guess tells me that most tractor's COG (w/o additions) is a few inches to 1/2 a foot higher than the rear axle.

Or when eyeballing tractors for purchase, use the height of the rear axle centerline divided by width measured to the outside of the rear tires to get comparative data. That ratio should be 0.25 or less for stability.

For example, my 1964 MF135 diesel has a 0.24 ratio with those 18.4 x 16 inch rears on 16 inch diameter rims.

MF135 stump1 (1).JPGMF135 stump2.JPG

It helps that the 135 is a straddle tractor with an inherently low COG. When seated your legs straddle the transmission like riding a horse. Most modern tractors are platform designs where you sit higher with the soles of your shoes above the top of the transmission. That raises the COG. Case/IH has its JX series that it calls "straddle" tractors. Unfortunately, these tractors are a lot larger (60-95 hp engine) than CUT size.


Good luck
 
   #5  

MossRoad

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Aug 31, 2001
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South Bend, Indiana (near)
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Power Trac PT425 2001 Model Year
My old late 70's IHH2500b was a low boy, as they say, in that you had to straddle the transmission hump. It felt very stable.

My current Power Trac PT425 is very low as well. You straddle the center links (no transmission, and it's articulated.) I'd guess the soles of my feet aren't a foot off the ground. Very, very stable.
 
   #6  

GirlWhoWantsTractor

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Apr 25, 2015
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The Mountains of Virginia
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2018 Mahindra 26XL HST, Husqv GT48XLsi & YTH48LS
I have a whole thread on this subject which you might have seen, Using a Tractor on Mountain Property, as that was a big concern of mine as well. I found the stock JD to be somewhat less suitable for the steep in a couple of ways: higher ground clearance plus quite a bit of cast aluminum down below, where other tractors have cast iron, resulting in less weight down low where you want it = higher COG. Plus I looked at WIDTH and LENGTH, aiming for a tractor that was at least half as wide as it is long, as sideways tipping is the biggest danger, and the stock JD's were a bit longer and narrower than what I chose. Also taller. Now if you add wheel spacers of course that would make a big difference. Not knocking JD at all (know nothing about them except the specs). These are just some points to consider on steep slopes.

Seems to be the consensus here on TBN that, all other things being equal, a heavier tractor is more stable, so maybe your dealer is just trying to make a sale? Not very responsible of him, if true.

MossRoad has a point; maybe you should consider a Power Trac.
 
   #7  

jeff9366

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Gilchirst County North-Central Florida
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Kubota Tractor Loader L3560 HST+ ~~~~~~~~~~~~~~ 3,700 pounds bare tractor; 5,400 pounds operating weight ~~~~~~~~ 37 horsepower
My current Power Trac PT425 is very low as well. You straddle the center links (no transmission, and it's articulated.) I'd guess the soles of my feet aren't a foot off the ground. Very, very stable.


Maybe you should consider a Power Trac.

Purceville, Virgina to Tazewell, Virgina, home of Power Trac = 309 miles via I-81 South.
 
   #8  

ericm979

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Nov 25, 2016
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Santa Cruz Mountains, Ca
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Branson 3725H
Not too bad a guess according to Tractor Stability - eXtension.

That article refers to a 2WD tractor. That's a potential source of confusion, at least for me. When ag. engineers talk about 4WD tractors, they are referring to the large articulated ag. tractors with front and rear tires of the same size.


Steve


That's a good article and it links to this: Tractor Overturn, H.J. Sommer III
a bunch of videos of a remotely driven test tractor rolling over in different situations.

The axle, transmission and engine crankshaft are all in a line. The COG will be higher than that due to the engine cylinders and head, radiator, operators station, operator, etc. If the fuel tank is above the engine that will raise the COG too. If it's down low like on many tractors now it'll lower the COG. I had smaller wheels and tires put on my Branson, and 2" spacers between the rear wheels and axle. The R4 tires are wider than R1s as well. This tractor is much more stable on slopes than my old Kubota B7100 with R1s set out as far as they go. It's a bit lower than with the standard wheels and tires so I do need to take more care when operating.
 
   #9  

buckeyefarmer

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Jun 25, 2005
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MD
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Kubota L3940 L5030 MF205-4
I bought R4s on my L5030, thinking the wider width would be better on hills. However, they slide on hillsides, R1s are better.
 

Citydude

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Nov 14, 2013
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Northeast Wyoming
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Kubota L4060 HSTC
The 6" spacers, r1 tires set to the widest point and loaded tires made a world of difference on my L2501.
 
 
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