CenTex Farmall
Well-known Member
Has anyone ever calculated or observed the center of gravity (or center of mass for you S.I. types) of a plain M? Assume a gasoline tractor with no ballast or wheel weights.
- Thread starter CenTex Farmall
- Start date
The center of gravity in a moving vehicle is not static unless it is traveling straight and not accelerating or braking. Vertical acceleration can also happen when dropping a tire into a gopher hole or hitting a boulder.
Were you planing on setting up a three axis G-force meter and display on a M? Why not select a lower gear and watch where you are going?
Were you planing on setting up a three axis G-force meter and display on a M? Why not select a lower gear and watch where you are going?
CenTex Farmall
Well-known Member
Interesting, two replies and both concerned with tipping.
No, I'm interested in the static C.G. on the longitudinal axis. Stationary tractor on level ground. My concern is more in the way of transporting and securing.
If I had way to hoist one vertically I could determine it more or less by observation.
By the way Wardner, I'm going to come to your house some time just to look at some of the stuff you've cooked up and have sitting around!
No, I'm interested in the static C.G. on the longitudinal axis. Stationary tractor on level ground. My concern is more in the way of transporting and securing.
If I had way to hoist one vertically I could determine it more or less by observation.
By the way Wardner, I'm going to come to your house some time just to look at some of the stuff you've cooked up and have sitting around!
CenTex Farmall
Well-known Member
No, that I can do.
I was just curious if anyone had ever determined the C.G. with any degree of precision. Intuitively I would think it would somewhere near the front of the transmission.
It's more of a "Gee Whiz" question but may be useful for tractor pulling too.
I was just curious if anyone had ever determined the C.G. with any degree of precision. Intuitively I would think it would somewhere near the front of the transmission.
It's more of a "Gee Whiz" question but may be useful for tractor pulling too.
You can find the static longitudinal CG with a bottle or floor jack. May want to put a cushion between the tractor and jack to avoid a high pressure point.
Don't most trailers come with a tongue weight rating? Place an equivalent amount of weight on your truck hitch or above on the tailgate. Measure the distance from the ground to hitch. Unload the truck and re-measure. Use that difference if it doesn't exceed the truck specs when positioning the tractor.
Drop by anytime. We're only 1500 miles apart. Bring some warmer weather and a hot chocolate please.
Don't most trailers come with a tongue weight rating? Place an equivalent amount of weight on your truck hitch or above on the tailgate. Measure the distance from the ground to hitch. Unload the truck and re-measure. Use that difference if it doesn't exceed the truck specs when positioning the tractor.
Drop by anytime. We're only 1500 miles apart. Bring some warmer weather and a hot chocolate please.
Ernie, IMO it will be some where @ mid Torque tube point. As a kid I have cut donuts in 4 in of snow in Hi gear at full throttle, with a tricycle front gas M with water in the tires and 1 cast wt. Very Dumb in retrospect!! Call Me and we will Who-raw a while, about it.
Later,
John A.
Later,
John A.
Janicholson
Well-known Member
Wardner is correct. Use a nice bottle jack and a hard wood block. I would start at the front edge of the transmission (behind the inspection plate for the Liftall drive shaft) if the front tires raise, it is farther back. Lift only until a tire just leaves the ground, front or back. Jim
rustyfarmall
Well-known Member
I asked the same question several years ago. I THINK the answer was 20" ahead of the center of the rear axles. I have also found that to achieve the absolute BEST ride while hauling any tractor on a tandem axle trailer, drive the tractor onto the trailer forward, and center the rear wheels BETWEEN the trailer axles.
If you know your tractor's total weight, the weight on the front axle and the length of the tractor's wheel base you can calculate the static center of gravity.
(Front axel weight divided by the total tractor weight) x the wheel base = distance from rear axel to the center of gravity.
i.e. if:
WB is 100 inches
total weight is 6000 lbs and
front axle weighs 1500 lbs
(1500lbs / 6000 lbs) x 100 inches = 25 inches ahead of the rear axel.
An easier way to think of it is the percentage of the weight on the front axel can be multiplied by the lenght of the wheelbase to find the CG.
If 25% of the weight is on the front axle the center of gravity is 25% of the wheel base ahead of the rear axle.
(Front axel weight divided by the total tractor weight) x the wheel base = distance from rear axel to the center of gravity.
i.e. if:
WB is 100 inches
total weight is 6000 lbs and
front axle weighs 1500 lbs
(1500lbs / 6000 lbs) x 100 inches = 25 inches ahead of the rear axel.
An easier way to think of it is the percentage of the weight on the front axel can be multiplied by the lenght of the wheelbase to find the CG.
If 25% of the weight is on the front axle the center of gravity is 25% of the wheel base ahead of the rear axle.
Bob M
Well-known Member
If you have access to a platform scale, CG for your tractor is simple to determine:
1 - Measure the wheelbase - ie. the distance between front and rear axle centerlines. (For an M it should be 94")
2 - Scale/record the weight on the front and rear axles.
3 - Calculate CG location:
weight front axle / total tractor weight x wheelbase
The result is the distance CG is ahead of the REAR axle.
----
Example: You scale 2,000# front, 3,000# rear (hence total tractor weight = 5,000#) and WB is 94":
2,000 / 5,000 x 94 = 37.6
CG then is 37.6" ahead of rear axle centerline.
1 - Measure the wheelbase - ie. the distance between front and rear axle centerlines. (For an M it should be 94")
2 - Scale/record the weight on the front and rear axles.
3 - Calculate CG location:
weight front axle / total tractor weight x wheelbase
The result is the distance CG is ahead of the REAR axle.
----
Example: You scale 2,000# front, 3,000# rear (hence total tractor weight = 5,000#) and WB is 94":
2,000 / 5,000 x 94 = 37.6
CG then is 37.6" ahead of rear axle centerline.
CenTex Farmall
Well-known Member
I've got in mind to build a low deck trailer for two tractors, one in front of the trailer axle and one somewhere partly over the axle. Axle would be a rear end from a truck. It's just an idea in my head and may not work at all one I really get to measuring.
1500 miles can go by fast at 450 knots...
I'll be glad to share the weather. 60 degrees and clear today!
1500 miles can go by fast at 450 knots...
I'll be glad to share the weather. 60 degrees and clear today!
CenTex Farmall
Well-known Member
Haven't talked to you in while. Will call soon and catch up!
rustyfarmall
Well-known Member
(quoted from post at 10:56:26 01/22/11) With all your theories, I would say just about where the swinging drawbar mounts...
Which, if you measure that distance, I think it will be right at 20 inches.
GeneMO
Well-known Member
- Location
- Pilot Grove, Mo.
Good thing you didn't hit a frozen cow pile with the rear wheel !!!
Gene
PS, I have done the same thing
Gene
PS, I have done the same thing
SadFarmall
Member
Swinging draw bar is the spot. My grandfather always bought IH tractors and not Massey Ferguson because of the draw bar set up… impossible to turn over the tractor. The number of people killed on grey Ferguson tractors is very high.
CenTex Farmall
Well-known Member
I hadn't thought of this one and would be a perfectly good way to directly observe the spot.
CenTex Farmall
Well-known Member
Thanks, I have not seen that site before. Good information!
CenTex Farmall
Well-known Member
I appreciate the input, ideas and formulas.
Thanks guys!
Thanks guys!
Will this be a gooseneck, or a semi-trailer? If it's a semi-trailer, to be pulled by a heavy truck and not a pick-up, just put the axle in the back. If it'll be a gooseneck, I'd want more than one axle.
I think you would want the two tractor's centers of gravity centered on the point where you would have the center of gravity if you only had one tractor on.
Sorry in advance for the hi-jack.
About it being impossible to roll a tractor over backward because of where the front of the swinging drawbar hooks, that's BS. It's how high and how far behind the axle the hitch point is. The Fords and Fergusons roll easier because the hitch point is up high and close to the rear axle. If you moved the hitch point back and down a little, or even just down, they wouldn't flip as easily. If you doing something like dragging logs, you can get the same effect by using a longer chain. You want the drawbar to point at the draft center (the center of the load, on a log it would be the stump, on a trailer, where the tires meet the ground, on a plow the center of the middle bottom, or halfway between the middle bottoms) before the COG comes up over the rear tires. Ideally, for traction, it would be just as the front wheels are coming off the ground. Once the drawbar points below the draft center, the load will actually pull up on the drawbar. If it starts bucking, it can still go over, but it gives you a few seconds to hit the clutch first, at least.
There is a section in the old JD book "Operation, Care, and Repair of Farm Machinery" about finding and adjusting plows to the draft center.
I think you would want the two tractor's centers of gravity centered on the point where you would have the center of gravity if you only had one tractor on.
Sorry in advance for the hi-jack.
About it being impossible to roll a tractor over backward because of where the front of the swinging drawbar hooks, that's BS. It's how high and how far behind the axle the hitch point is. The Fords and Fergusons roll easier because the hitch point is up high and close to the rear axle. If you moved the hitch point back and down a little, or even just down, they wouldn't flip as easily. If you doing something like dragging logs, you can get the same effect by using a longer chain. You want the drawbar to point at the draft center (the center of the load, on a log it would be the stump, on a trailer, where the tires meet the ground, on a plow the center of the middle bottom, or halfway between the middle bottoms) before the COG comes up over the rear tires. Ideally, for traction, it would be just as the front wheels are coming off the ground. Once the drawbar points below the draft center, the load will actually pull up on the drawbar. If it starts bucking, it can still go over, but it gives you a few seconds to hit the clutch first, at least.
There is a section in the old JD book "Operation, Care, and Repair of Farm Machinery" about finding and adjusting plows to the draft center.
CenTex Farmall
Well-known Member
Thanks for the input.
I have a copy of the JD book. I'll take a look in it.
I have a copy of the JD book. I'll take a look in it.
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