Weight distribution

[JCA]

When a typical compact tractor is sitting on a flat surface with an FEL on the front, rear tires loaded, how is the weight distributed? How much is on the front tires, how much is on the rear tires?

Thanks,
Jim

 

[gone]

Now you asked a question with so many variyables that no one could answer. but lets wait and see.

 

[F_22]

Seems like a reasonable question to me, and I'm an engineer (formerly automotive, now aerospace). Note that he said "typical". He's not looking for exact weights to the pound, just a rough percentage front/rear. I have read that a bare compact tractor is typically 33% front / 67% rear.

After having my tractor for 6 months and reading these forums for about a year now I've concluded that these tractors are not well designed for the uses that they're put to.

With very heavy duty rear axles and tires, and relatively light front axles and tires, they're obviously designed for 3-point draft applications with ground engaging implements. But my impression is that most are purchased with a FEL and that is the most commonly employed implement. Even if the FEL isn't used most often, it is usually left attached. In my case (NH TC33D with 7308 FEL) the FEL adds 800 Lb to the front end of a 2500 Lb tractor, and I'm sure it biases the weight distribution significantly forward. BTW, I have 600 Lb liquid ballast in the rears but it still isn't enough to keep the back end down without carrying the rotary cutter, which severely limits maneuverability in all my trees.

 

[gone]

Even though your an enginier, and gess who diesingns these things, i'll agree these tractors aren't designed for what we do to them. I have seen broken front axeles and i have said in the past to keep front wheels turned in there are guys that will say turn them out but i don't think they realize the stress the front end will take expecally if the axle hits the stops on one front wheel. Yet we all want more lift on loader, well mine lifts enough i don't want more and mine will last! but back to the weight the loader just blew the bias out the window as did loaded tires the wheights you put are recomended not an auctal. i'll bet the tractor stock is probly off the mark. close maybe! Cat enginers suck they down size parts and when they break there is always an update kit to fix it,at first its the operator then after a couple times the update kit, then they still don't admit it was a problem! I'm not picking on you just stating enginers mak mistakes even in the const. field i see scewd up plans every day,water will run up hill acording to the plan.

 

[F_22]

Dang! I couldn't have said it better. Literally.

 

[theonlybull]

I have read that a bare compact tractor is typically 33% front / 67% rear.


being an engineer, you should stand back and look at a bare tractor. i belive you have your %'s reversed, there is alot mor weight on the front axle, then the rear. this is from the age old design of rear mounted accessories..

 

[Poppa]

</font><font color="blue" class="small">( there is alot mor weight on the front axle, then the rear. this is from the age old design of rear mounted accessories.. )</font>

Kind of wondered about the aformentioned weight distribution myself. Figured there must be a reason why the big old engine sits on the small front wheels and the big wheels just hold the Farmer /forums/images/graemlins/smirk.gif.

Mike

 

[AndyMA]

I've been following this discussion and I think it's going in the wrong direction /forums/images/graemlins/confused.gif Acording to everything I've read, static weight distribution should be set as close to 60% rear 40 % front as possible when equiped as going to be operated. Many of the posts I read on this board just don't run enough rear ballast to use their loaders at full capacity. As I've said before, the specs on my Ford 2120 require filled tires AND metal wheel weights AND a rear implement to use loader at rated capacity. Most of the smaller New Hollands require both filled tires and either metal weight or an implement to use the loader at rated capacity. No compact tractor should be set up with more weight on the front axle than the rear. The front tires don't have the load handling capacity of the rears, and neither does the axle. Stability will be an issue. Also when you look at a tractor, the rear definately weighs more. The larger rear tires, trans,and rear axle/ differential definately out weigh the engine. lighter front axle and other misc parts. Also the rear carries all the heavy 3pt, towing hardware and in most cases the fuel tank.
Just the thoughts of another engineer.

Andy

 

[Poppa]

Well, let me qualify this by stating that I am not an engineer. Nor an expert. nor even qualified to comment on this but hey what the heck.

Seems to me that Andy's post goes a long way towards asking a question I have seen in older threads. Are these tractors really designed to use a FEL to it's capacity?

When I think about the older tractors I think about a great big lever. As much weight as possible was placed forward of the rear wheels to off set the weight and drag of any implement placed on the back of the tractor. If I am wrong then I apologize and ask for enlightenment.

So, as I read Andy's Post it appears to me that to use a FEL we have to readjust that weight distribution through ballast, and implements. to offset the added front weight of the loader itself. Giving us the 60% rear, 40% front set up. THEN, the added load in or on the FEL cannot exceed the difference of the two.

Am I in Left field? /forums/images/graemlins/crazy.gif
Are we (well not me yet /forums/images/graemlins/frown.gif) overloading these CUTs

Mike

 

[gone]

I myself am noy going to worry about the weight dis. if i can move it without lifting a tire i'm going with it. you'd spend more time adding and loosing wheight than it would take to do the job. My bias is set to 4 wheels on the ground,no matter front or back. It's worked for 40 yrs. why change cause an enginer said thats the way it has to be, i think they should build them like they used to in stead of thiner and lighter,and if it brakes well make it heavyer atitude. the old designers made them to last and hold up, period.

 

[bebster]

One trick I've used recently when the FEL is a little full and heavy, is to extend the backhoe a little farther back. This helps shift the center of gravity to the rear and provide some temporary stability for that extra heavy load from time to time.

 

[KiotiJohn]

This is a quote from Firestone Tire Company on liquid ballasting of tubeless tires:

Step 2: Check for Proper Weight Distribution. If you find that the tractor is not properly ballasted, adjust it according to the manufacturer’s ballasting recommendations for weight split, total working weight and wheel slip.

Generally, the weight split will be 35 percent front, 65 percent rear. Once the tractor is properly ballasted, proceed to Step 3.

 

[Poppa]

</font><font color="blue" class="small">( When I think about the older tractors I think about a great big lever. As much weight as possible was placed forward of the rear wheels to off set the weight and drag of any implement placed on the back of the tractor. If I am wrong then I apologize and ask for enlightenment.
Am I in Left field? /forums/images/graemlins/crazy.gif
Are we (well not me yet /forums/images/graemlins/frown.gif) overloading these CUTs
)</font>

I don't know if it is Kosher to reply to yourself but I felt in this case I probably should.

The answer is no I am not in Left field, heck I never made it to the ball park. Knowing that I have never been the brightest bulb in the pack it just took me all day to realize why I am wrong.

For me to get a handle on this whole idea, I kept having to think of an old Ford N or JD B or something along that line. I kept thinking about keeping the tractor from doing an instant back flip whenever a plow hit the dirt. While that is important enough to help inspire the 3ph in the first place, I missed two huge problems with my idea that most of the weight was originally placed forward of the rear wheels.

The first is traction, A topic often discussed here and ignored by my Post. If the weight isn't on the Drive wheels then they spin, pure and simple. The second problem is that if they had put that much weight over the skinny front wheels then the first time it was too muddy, the tractor would just bury the front end until the rear wheels lost traction.

The 60:40 or 65:35 ratio back to front does answer all three of my questions. The back wheels get traction, the front wheels aren't so overloaded they become trenching tools. But there is enough weight forward to help stop the back flip assuming reasonable use of a rear implement. Heck, forty percent of 5000 lbs is still a ton (literally /forums/images/graemlins/laugh.gif) of weight forward of the rear wheels.

So, even though I am still not sure whether these tractors are truly built to use a FEL to their full capacity I have definitely learned some good stuff.

Thanks and I apologize for my ignorance. At least At my age I have learned that whenever I start to think I am the smartest person in the room. A red flag goes up in my brain suggesting that I am wrong or the room is empty /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

Mike

 

[gone]

Hey, two diffrent weight bias suggestions off the internet sites tire manufactures, 33% fr-67% rear ,and 35fr-65% rear how can the guys that build these things differ in opinion? maybe theres more than one formula? no that can't be sience is sience right.

 

[Henro]

<font color="blue"> Hey, two diffrent weight bias suggestions off the internet sites tire manufactures, 33% fr-67% rear ,and 35fr-65% rear how can the guys that build these things differ in opinion? </font>

I think in the practical world ( where I don't live all the time... /forums/images/graemlins/grin.gif ) they are essentially the same numbers... /forums/images/graemlins/smile.gif

 

[keeney]

A machine that is purpose-built to use a loader would look a lot more like an articulated wheel loader with the engine in the back and big wheels in the front. Skid-steers also have the engine in the back. This configuration lets you use the engine weight also as ballast, puts the operator where they can see, and puts a heavy-duty axle and wheels under the fulcrum point of the loader.

Putting a loader on the traditional tractor configuration is a compromise design that lets you get multi-purpose use of a machine that's orginal design intent was to pull ground-engaging implements like a plow.

Another issue is weight. The traditional tractor configuration (along with the 3-pt hitch configuration) is intended to maximize traction without becoming so heavy as to overly compact the field it is driving on.

So another big differences is overall weight. Even a small skid steer is typically upwards of 7500 lbs. Most CUT's discussed here are in the under 5000-lb class. It takes some pretty tricky engineering to build a machine that can lift more than its own weight cantilevered outside of its wheelbase.

So, to make the compromise work better, add ballast to the back.

- Rick

 

[jmc]

JCA,

If you're serious, I think you could measure the distribution as you loaded it on a two wheeled trailer. Someone tell me if this logic is wrong.

1) Hook up the empty trailer and measure the height of the hitch.

2) Make a chalk mark on the bed directly over the trailer axle.

3) Drive the tractor up on the trailer until the hitch height matches the empty height measured previously. The tractor is now balanced over the axle.

4) Make anothe chalk mark on the bed at the midpoint of the tractor's wheel base.

5) Divide the distance between the two chalk marks by the length of the tractor's wheel base. At .1, its 60%/40%. .2 =70/30. .3=80/20 .4= 90/10, and of course, 0 is 50/50.

John

 

[LBrown59]

</font><font color="blue" class="small">( One trick I've used recently when the FEL is a little full and heavy, is to extend the backhoe a little farther back. This helps shift the center of gravity to the rear and provide some temporary stability for that extra heavy load from time to time.

)</font>

You could also add more weight by filling the hoe bucket with dirt or something.