Tractor Weight

Reading Dustyah's post on the Case forum about Too Much Weight got me thinking about my own ongoing project. I know tractors have a maximum weight rating, but what exactly does this entail? A tractor can be too heavy in regards to what (field work, traction, hp-weight ratio...)?

What problems are associated with being too heavy? Of course, short of way overdoing it and blowing out front hubs and spindles, snapping axles, etc.

I'm sure it depends greatly depending on the application, but what is the fudge factor with the specified max weight?



According to tractordata my Case 1190 is listed as shipping at 4620 lb and having a max weight capacity of 7000 lb. I won't be doing any "heavy" traction work when fully loaded, but in the winter months by my calculations it will be flirting with that 7000 lb mark. When pushing snow there will be some slippage and some weight will be lost on the front end because the plow will be sitting on the ground when plowing, so it shouldn't be an issue but like I said, it will be flirting with that 7000 lb max weight capacity when the plow is up.

Tractor - 4620 lbs
Front Weights - 3x 79 lb = 240 lb
Wheel Weights - Unknown
Snow Plow - 600 lbs (as I recall from talking to the manufacturer)
Ballast Box - iMatch Ballast Box w/ Sand = 616 lb Steel Plate - 580 lb
Me - 200 lb

Total Weight (short wheel weights) - 6860 lb give or take 100 lb for guesstimation.

P.S. - Does anyone know what those rear wheel weights might weigh or what they came off of? Cast into them is - BW401A D22T

The previous owner of one of my tractors (M670 Super MM) had fluid in the rear tires, over 80% I believe. I noticed when I was plowing that the tires would ripple a lot on the sidewall. I did remove the fluid as I had basically no slippage at all pulling. No slippage can lead to damage of drivetrain parts.

I can't specifically answer your questions but I can tell you that I bought a 50 JD that a man had almost broke in half. As a matter of fact it did finish breaking when we were loading it on the trailer. He had stacked a load of weight on the front and had been feeding large round bales with it via the 3 point. It cracked all the way around the transmission housing/casting. gm

Weight attached to axles or wheels do not count toward applied weight to the frame. The distande that the plow is located ahead of the front axle increases the load on the axle and removes it from the rear where it is needed for traction. I would shorten the plow as much as possible. You will spend as much time with bly the plow up, as down, and even then it might not be fully down because of lawn or gravel. The mounting point could be moved rearward [possibly 2 feet] making for much better directional controll, and weight distribution. Tire chains are a must. Jim

If the plow is moved back, which is an excellent idea, the one thing to watch is that it doesn't hit the front tires when swung to the side. I usually realize things like that AFTER going to all the work of remounting it.

We have very heavy clay soil around these parts so most the guys like to have dual tires or extra wide tires so as to minimize soil compaction when plowing and planting. JD

Problem with fluid is you are reducing air volume. Lose a little and you are way low in a hurry on psi.

Right, I made sure to measure numerous times before building the mount. The picture doesn't show it well, but when the plow is angled all the way one direction or the other I believe I left about 6-8" between the moldboard and the front tires. Anyway, it's mounted as far back and I could get it and still be comfortable with the front tire clearance when the plow is angled.

That picture was taken right after I got all the framework built and mounted, so it was just kind of mocked up and not even wired or anything. Since then I have taken the old cutting edge off and built a new one with flat iron and some 2" pipe so I don't remove my gravel driveway when plowing. I also cut off the rubber flap right where the break is there at the top of the moldboard. I need to get some pictures taken and put together of everything since it's more or less completed: I like putting together portfolio's of all my fabrication projects.

This is OT w/respect to your weight question, but x2 on moving mount point. FWIW, mounts I've seen for plows that size have been set on the main trans/rearend casings, not on the more fragile front axle. This moves the pushing forces to those more substantial castings. If I had no choice but to fab a mount to front axle, I'd use it only in creeper gear. Outcome might not be good if moving at a good clip and one corner bites in.

I may be misunderstanding the replies regarding the mount, and if I am I apologize. Here are a few pictures. It is mounted ahead of the transmission but it is mounted to the frame not the front axle specifically. Speed was not in the plan when building, I figure 3 or 4 mph is plenty to push snow on my driveway, no need for 8-10 mph. The tractor wouldn't handle it anyway.

It is not the axle, )which will get the weight in all cases) it is the front overhang. Your design is strong and appears well made. it also appears that, with little effort, it could be moved rearward quite a large amount. Here is why:
The front axle is a fulcrum (pivot point) for the support of the blade. When the blade sticks out as far as yours, the weight of the blade (when lifted) is removed from the rear axle and transferred to the front axle. This is like having a heavy kid on an equal length teeter totter. In addition, the farther ahead of the axle the blade is located the easier it is to have the blade slide the steering tires sideways. the last reason is that putting it away requires substantially more room. Jim

If you hit much those angle irons are going to fold up.

Looks good. I would add a couple of 2inch tubes from the angled point on your angles back to the draw bar to take the guff when plowing. If you hit ridges of dirt or gravel in the snow from frozen tracks it is going to fold up like a pretzel. The tubes will hold it. I would also put a piece in an X on the verticals by where the blade pins on. Then put about a 1000 pounds behind the rear axle or load the tires. Snow is like dirt it takes weight and power to move it.

I have nearly that same set up on my tractor. I filled the rears and ring chains. When I added the rear weight I put about 500 lbs on the ends of my 3 point arms. I could push the world over but was afraid of tearing up the drive line,the tires wouldn't spin. Also the plow was getting the snot beat out of it hitting the piles when they got good and froze up especially after a freeze thaw cycle. I leave the box in the pole barn now.

I was kind of afraid that I would pop a tire and watch all of the tractor dissolve with the fluid spraying all over. I figure I would put cast iron weight on when I need it.

I read somewhere, a lot of years ago, that Purdue u. or U of Il. did a study and said that when pulling a heavy load, a tractor should have about 15% wheel slippage.

Since you have it built, you might consider boxing the angle with another angle to make a square tube. Skip weld 2-2 if you like. adding a pusher from the rear is also a great idea.

Ive always heard that too that you need a certain percentage of slippage. Good to know the info you posted. Ive always read in the operators manuals that if the tread impression is slightly shifted you are weighted properly. If there is no impression, not enough weight, full impression, that isnt shifted, too much weight.

As Mike in KY and Alan K said you are supposed to have a certain amount of tire slip when pulling a heavy load in dirt, I agree that it is 15%. I used to have a 1490 DB Case and it told about it in the owners manual so I expect that it is in your manual as well. Slippage when plowing snow can be a good safety valve. I agree with others that your plow is hanging out a little far in front and that it could go back at least eight inches.