4 wheel drive all the time? or just when needed

[ljjhouser]

Were you sitting in the same seat with me? See my earlier post.. did exactly the same as you.. hit the steepest part of our hill, had to make a 90 degree turn, the rears locked and sliding... I stopped about 200 yards downhill... It is a horrible feeling...

Ha- I did read your post. reminded me of my experience. And made me flash to that same sick feeling you had. But you went a lot farther than I. There was another time also - operator error. On my Kubota. My drive (luckily unlike yours) has the 90 degree turn at the top. The rest is somewhat straight. A turn at the bottom could be aweful. It is also concreted about 1/2 the distance (on top). I was on the road to help someone so slipped it into high gear to go there. Days later, I was going down the ma drive, so slipped into low gear. HST. As is turned the corner, the tractor accelerated quickly out of control (on concrete). I let up on the HST Pedal and still increasing. I slammed on both brakes and skidded the back tires. And came to a stop. I did not get it locked into low gear and it popped out of gear as I made the turn to downhill. Scared the hell out of me. I guess we, after something gets our attention, make mental notes of those events. I told my wife about both so she would not make the same mistakes I had learned from. But I am sure I will remember now. Hope she does also. Nothing like scaring you to get your attention. Anyway, great post and I will try to think of it anytime I decide to operate on a hill with ballast.

 

[Diggin It]

There is never any one answer to this question. It's all about your own circumstances. I just rolled over 400 hours. Probably 350 of those have been in 4WD. I have NO level ground ... none. Going downhill in 2WD was something I did once. Never again. Uphill in 2WD in not possible.

The ONLY time I'm not in 4WD is when I'm on the paved road going over to a neighbor. When I cross my paved driveway, I'm careful about how I steer, if at all. Very gradual.


A comment on brakes. These small machines don't have any. Not in the traditional sense. None of the wheels have brakes at all. The only braking is called a 'wet brake' inside the transmission and it can easily be overcome by gravity, meaning even in 4WD, stepping on the brake pedal may not help (much) if you're already rolling too fast downhill.

 

[PILOON]

One wild ride with weight in FEL going down hill in 2 wheel drive will rapidly train you.
Trust me on that.
Buckets make lousy brakes!

 

[bearthebruce]

One wild ride with weight in FEL going down hill in 2 wheel drive will rapidly train you.
Trust me on that.
Buckets make lousy brakes!

On my wild ride, I had the forks on - loaded with a 350lb machine - not the bucket.. I was not going to try putting the forks down... the bucket curled I might have tried.. but not forks. The fork frame catching something and me going pinwheel was what I was thinking.

You are correct. One wild ride will not soon be forgotten.

Enough. The OP I think has the idea. If he is on flat land, use 4w drive when better engagement is needed. If on hills, think and decide.

 

[Doughknob]

There's really no debate....
.

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

 

[IndyJay]

Buckets make lousy brakes!

They beat the alternative...

 

[old and tired]

I don't have a flat piece of ground so I'm always in 4 wheel drive... I don't mind having to buy new front tires or shoot, a new front axle if I have to. I've taken my share of uncontrolled down hill skids to know that one bad accident would cost more than tires and an axle....

Been there and done that and had to burn the underwear....

I have R4 tires and there is a good reason you can not buy a 2 wheel drive tractor with R4's...

 

[JasperFrank]

Switching it up, got me in more trouble then it was worth, if I had forgotten it was in 2WD, due to the braking issues already addressed. So the default is always 4WD. The only time I'll set to 2WD is if I'm mowing/pulling -dry material on reasonably flat dry ground, driving for a distance and I can make wide turns. I rarely run on any pavement, which I would set for 2WD. Seat of the pants, I couldn't tell, power-wise, if it was in 2WD or 4WD. Recently, one of the front wheel-axials, just pulled entirely out of the drive hub. Easy fix, but I was surprised that the wheel-axial was held in by just a small Cir-clip. I was in 2WD when this broke, in a tight turn, with the FEL loaded. If I had been in 4WD, I'm thinking the stress on this axial would have been less as the wheel would have been pulling forward instead of being pushed hard to one side to get out of the hole it had fallen into. I had forgotten I was in 2WD cause I was in mowing mode, but thought, "Lets just transport some rocks with the FEL while I'm going that way." That was the mistake. Though the axial needed a rebuild here any way after looking at the old parts. So the take is.... sometimes using 4WD, most of the time, "saves money."

 

[Jstpssng]

I switch back and forth quite often, as I spend a fair amount of time on the road, running back and forth from garden to house and back again. Most of the time I'm in 4WD while working.

 

[Williy]

You could always get a couple of anchors boats use them
Then again you could always drop your bucket to dig in

willy

 

[Jstpssng]

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

 

[Berlock]

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!

 

[SmallChange]

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.

 

[rScotty]

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

 

[bearthebruce]

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.

Now you tell me!

 

[mo1]

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.

 

[mo1]

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.

 

[WranglerX]

Never on pavement, and only when I need it on "dirt"....

 

[SmallChange]

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....

 

[Diggin It]

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.