Is Full Time Use of 4WD a Problem?

[ovrszd]

Also worth mentioning, some folks need 4WD because their tractor has a FEL and they have no counter weight (or not enough counter weight) on the 3 pt hitch. Just the added weight of an empty FEL will cause loss of traction at the rear tires. So having the fronts pulling only masks this problem.

We want the rears to do most of the work and the fronts to help. Just look at the size of the rear axle/tires VS the front...

Another very good point. Tractors are designed to absorb most of the work load with the rear tires.

When I bought my M9540 with FEL and without loaded rears. It would not back up any kind of incline in 2wd. I was very shocked!!!! A CUT or Utility tractor is not balanced like an AG tractor. With Cast Iron centers in my rear wheels and with 1350lbs of fluid in my rear tires my tractor is still 10lbs heavier on the front axle than the rear.

 

[DarkBlack]

I've never met anyone who damaged their tractor by leaving it in 4x4, but I met someone who damaged it by shifting in/out a lot. After that he left it in 4x4.

 

[Bluegill2]

Another very good point. Tractors are designed to absorb most of the work load with the rear tires.

When I bought my M9540 with FEL and without loaded rears. It would not back up any kind of incline in 2wd. I was very shocked!!!! A CUT or Utility tractor is not balanced like an AG tractor. With Cast Iron centers in my rear wheels and with 1350lbs of fluid in my rear tires my tractor is still 10lbs heavier on the front axle than the rear.

Take the loader off and it'll balance more like a AG tractor. Or add the same weight as the loader to the 3 point and you can back up a hill in 2WD.

 

[Beltman60]

Just my opinion ... And it's not worth much !! But I assume if tractors were meant to run in 4x4 all the time ... The mfgr would not install a lever to engage or disengage ... Use it when needed

you would still need to take it out of 4x4 for on payment

 

[Danny C]

Lets assume that from the factory with new tires, both front and back are matched in rolling speed. The front tires are is in sync with the rear tires.

If we use the formula R (tire radius) times 3.14152 (Pi) then we get circumference. Lets say the tires when new, with no load in the bucket, have a radius of 15" on the tractor. That gives us a circumference of 47.178 inches. Remember that at this point the gearing is perfect to match the rolling speeds of both front and rear axles.

Now lets say we have used the tractor for a few years and the tires are down by maybe 3/4" in tread height on the front. Let's further assume you have 400 pounds in the bucket causing the tires to "squish" under the weight maybe 3/4". That gives a combined reduction in the radius of 1.5"

Again using the circumference formula but changing the radius to 13.5" we get a circumference of 42.410 inches.

There now exists a conflict in rolling axle speed between front and rear. This will be taken up by one or the other axle forcing the tires to skid on the ground surface (the ground covered must be the same). By shifting out of 4WD you eliminate the conflict and allow each axle to have independent rolling speeds.

I use 4WD only when I need it.

My two cents.

The same thing happens when you wear your rear tires faster than the front tires! 4wd on grass, gravel and soft ground will not be a problem and will not wear out drive components prematurely. Furthermore, running in 4wd will wear your tires evenly making sure their circumferences stay the same in relation to the gear ratios.

 

[blueriver]

I've never met anyone who damaged their tractor by leaving it in 4x4, but I met someone who damaged it by shifting in/out a lot. After that he left it in 4x4.

Probably force shifting at the wrong time??

 

[TripleR]

As mentioned, some tractors are run on the road, so it is only natural to be able to select 4WD/2WD in the spring and fall our roads are filled with tractors/combines etc.; doubt any of us are going to change the way we do things.

 

[Bluegill2]

Another way to look it, is if you are using 4wd because you don't have enough traction at the rear tires, you really have a ballast / counter weight issue. In this situation you are using the traction of the front end to compensate for less traction of the rear tires. This well cause front end issues at some point!

 

[RoyJackson]

Probably force shifting at the wrong time??

My manual states I can shift into MFWD "on the fly"...I don't. I stop completely and shift.
We don't know what actually caused this tractor's failure...or if the shifting was actually the primary cause.

 

[TripleR]

Another way to look it, is if you are using 4wd because you don't have enough traction at the rear tires, you really have a ballast / counter weight issue. In this situation you are using the traction of the front end to compensate for less traction of the rear tires. This well cause front end issues at some point!

I have great ballast until I start using it such as a box scraper, to compensate I will need to add wheel weights then I'll be carrying unneeded weight the rest of the time; seems like there's always something.