4 wheel drive all the time? or just when needed

   #31  

Jstpssng

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Dropping the bucket when going downhill out of control can lead to less than desirable results.
 
   #32  

Berlock

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I do less damage to my lawn in 4WD than in 2WD and I don’t know why.

Perhaps distributing the torque between 4 wheels just results in less slippage than between 2.

We should be able to use 4WD without being worried about the front axle failing, seems kinda ridiculous.
Better not go over too many bumps or the useless springs under my seat might wear out!
 
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   #33  

SmallChange

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New Holland WM25 with 200LC front end loader, filled R4 tires 43X16.00-20 and 25X8.50-14 (had a Kubota B6200D with dozer and R1 tires)
Dropping the bucket when going downhill out of control can lead to less than desirable results.

Agreed. But, ANYTHING when going downhill out of control can lead to less than desirable results.

We're making this too complicated. It's simple:

1: When you need 4WD, in low traction conditions especially with too much front weight and not enough rear, use it.

2: When you need 2WD, in high traction conditions especially with lots of tight radius steering on grippy or sensitive surfaces, use that.

3: When either will work fine, congratulations, you're golden.

4: When you have started down a hill in 2WD and then the rear loses traction, without question you should time-travel back to before you started down the hill, and engage 4WD. You're welcome.
 
   #34  

rScotty

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Ha. There is Always a debate here! 😂. But i agree - only when needed.

Good call. Yes, I agree that there is always room for debate. When I said there wasn't any debate I should have included that I was only speaking about the way the mechanical parts are designed on our 4WD compact tractors.

Having different front and rear wheel to axle ratios and not having a differential in the connecting drivesahft means they should only be used part time in 4wd - and then only when the surface allows a tire to slip.

But as you point out that's just the mechanics of the situation. And it's only if having the drive system hold up is the most important thing. It might not be.

Other things count too. For a person doing a lot of hilly FEL work it might be worthwhile to use 4wd all the time and just expect to do front axle and driveshaft rebuilds periodically. That works for me, too. In fact we had an old 4wd PU we used that way. Kept a spare set of rebuilt axles and driveshafts to swap out.

It's just mechanical parts. Axle and driveshaft work is actually inexpensive, lightweight, and interesting to fix. Like a puzzle, and no nasty combustion soot to deal with.

rScotty
 
   #36  

mo1

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I have a bobcat 2025 (kioti) with 55 hours so far; got it this spring. I really only need to engage the front axle when moving dirt or slogging through muddy trails. All my mowing and manure spreading are easily done in 2wd. Any reason to use the front axle every once and a while? I don't really notice a difference either way; power or steering etc.

Only use mechanical front wheel drive on loose/slippery surfaces when the wheels are slipping/are expected to slip. Normally you should have MFWD off and only engage it when needed. If I am using a tractor with MFWD, it typically gets engaged a couple of times per year maximum. It can be handy to get a little more traction for ground-engagement tasks like tillage but the traction difference between MFWD and 2WD in a properly ballasted tractor is something like 10-15% at typical tillage speeds.

The mechanical front wheel drive system has no center differential and the front differential has a relatively slightly higher gear ratio than the rear to drive the front wheels faster than the rears. This improves traction and turning ability on slippery surfaces. The lack of a center differential will cause the driveline to bind when turning unless the front wheels can slip relative to the rears. The overdriven front differential will cause the front wheels to try to "outrun" the rears while driving straight ahead unless they can slip relative to the rears. Results are that you will ruin the driveline and tires if you run MFWD on hard surfaces with good traction. If you run MFWD on dirt that isn't slippery, you will be hard on the driveline and front tires as you will force the tires to slip a lot more than they otherwise would. You will also end up with a very wide turning radius due to fighting the lack of a center differential allowing the fronts to turn at different speeds relative to the rears.

One more warning about inappropriate MFWD use is to not use it to compensate for lack of appropriate rear ballast when using a loader. If you get poor rear tire traction with a loaded loader, you need more rear ballast, not MFWD. Insufficient rear ballast causes too much of the weight to rest on the front wheels and axle, which can cause flat or damaged tires and axle damage.
 
   #37  

mo1

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Agreed. But, ANYTHING when going downhill out of control can lead to less than desirable results.

We're making this too complicated. It's simple:

1: When you need 4WD, in low traction conditions especially with too much front weight and not enough rear, use it.

2: When you need 2WD, in high traction conditions especially with lots of tight radius steering on grippy or sensitive surfaces, use that.

3: When either will work fine, congratulations, you're golden.

4: When you have started down a hill in 2WD and then the rear loses traction, without question you should time-travel back to before you started down the hill, and engage 4WD. You're welcome.

I would modify these a little.

1. When you need MFWD because of low traction conditions in a properly ballasted tractor, use it. When you need MFWD because of too much front weight and not enough rear, don't engage MFWD, you need to add rear ballast.

3. When either will work fine, disengage MFWD.

4. When you have started down a hill and the rear loses traction, without question you should time-travel back to before you started down the hill and add sufficient rear ballast or back down the hill. If you still slip despite appropriate ballast, you should time-travel back and get R1 tires. If you already have R1s, you should re-evaluate what you are trying to do.

I can't stress the need for appropriate ballast enough. Using MFWD as a band-aid to try to get away without using enough ballast is what leads to dangerous slippage with lack of control and machine damage.
 
   #39  

SmallChange

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New Holland WM25 with 200LC front end loader, filled R4 tires 43X16.00-20 and 25X8.50-14 (had a Kubota B6200D with dozer and R1 tires)
Never on pavement [...]

I use it going down my steep paved driveway if I'm carrying something big up front. And I have an 800 lb ballast box, plus filled rears. I figure it's worth a little extra wear to have the extra safety. Now, if I had a gage that told me what downforce my rear tires were experiencing....
 
   #40  

Diggin It

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I use it going down my steep paved driveway if I'm carrying something big up front. And I have an 800 lb ballast box, plus filled rears. I figure it's worth a little extra wear to have the extra safety. Now, if I had a gage that told me what downforce my rear tires were experiencing....
A 'little extra wear' isn't the issue. There have been a few posts here over the years where the front drive system breaks and locks up when driving on pavement, causing a very sudden stop. As I recall, one guy almost got tossed over the hood.

The rotational rate is slightly different due to tire size mismatches, or so I've gathered from the mechanically minded who have tried to explain it.
 
 
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