4x4 Question

[Captinjack]

In West (by God) Virginia I always have mine in 4WD due to the hills, mud and slippery conditions.......same for my pickup that has chains on all four and never comes out of lo-lo. Some places you just HAVE to use the 4WD.

My tractor and pickup never leave the 75 acre property. It' so bad that I can't park more than 7 vehicles in an all weather flat spot on the entire property. I envy y'all with flat terrain, but wouldn't give up the mountains for a place where everyone wants to be (too many people), everyone wants to know what your doing (they're hurting my property value), everyone wants to say what you should do (don't even think about doing it without a permit), and everyone wants to charge you an arm and a leg for services (taxes).

I can well understand how some can get away with using 2 WD most of the time and I'll agree that if you can.......then go right ahead as it should be less wear and tear. But for some of us......we really don't have much choice.

 

[Volfandt]

Who was it that said "if'n you were to grad ahold of W. VA and stretch it flat then it would become one of the largest states in the Union?

I know whatcha mean about those mountains, they're all around my valley.

Volfandt

 

[HomeBrew2]

For those of you that insist on running in 4x4 all the time, here's my challenge to you. Engage your 4x4 on your lawn, turn your front tires halfway to the steering lock, drive forward until you have completed half a circle. Stop, lower your loader bucket (if so equipped), pick the front tires up until they are off the ground. Notice how they will "spin" as soon as you start lifting weight off them??? That's the torque and twist of axles, driveshafts, gears, etc., that is stored in your front drive system from turning in 4x4. Does that not bother you?? Then continue to drive around in 4x4.
...........................................................................................
Another easy example of this torque is to engage 4x4 on a gravel driveway, turn the front wheels to the lock either direction, drive forward and complete a full circle turn around. Notice how the front tires are scratching and clawing at the gravel??? That is happening every time you turn around in 4x4 regardless of what ground type you are on.

First, the two portions of your "challenge" post, that I have quoted, are mutually exclusive. The first portion, correctly, proposes a buildup of energy by, to put it simply, the rear axle fighting the front axle. The second quoted portion, correctly, proposes THAT energy being released periodicly thru the manuver. ... seems like there's some kindof an equlibrium law in physics and I think that is a good example of it.

So, for no good reason that I can think of, I just went out and took your challenge:
OF COURSE I did not perform your experiment on paving nor rock slabs. My soil is bullet-proof clay to clay-loam ... scarifiers bounce off it ... it's a desert here. I turned a circle at half lock, then I turned a few circles at half lock, then I turned a half circle at full lock, the several at full lock ... each time using the bucket to check for axle/drive train "unwinding" ... DID NOT HAPPEN! Did the same experiment with my '80 Dodge Ramcharger with 33x12.5 tires (jacking up after each trial) .... NO UNWINDING !

I'm wondering if your tractor and little jeep have fatigued axles and/or drivetrains. That is a possibility, by simple metalurgy.

So my question is ... if you're not on pavement (concrete, asphalt, soil cement, etc) nor raw rock, where's the APPRECIABLE wear that would lead to a repair that is out of the "norm" I propose that there is no evidence that such "increased" "measurable" wear exists when a tractor is driven in 4WD all the time on dirt, weather needed or not.

Cheers!

Cheers!

 

[SPYDERLK]

HomeBrew2, I have a BX1500 - similar to your tractor. There is definitely stress in the drivetrain in 4WD. Since these tractors are so close coupled actual windup is minimal. The tires just slip slightly and constantly. The speed match front to back is near perfect when going straight and becomes perfect in a gradual turn. After this point, turning sharper causes the front wheels to be pushed because the path they travel grows ever longer than the rears. This slipping increases your turning radius. Try comparing turning ability in and out of 4WD. If youre just turning on level ground the 2WD drive mode will give a tighter turn because the front tires are allowed to rotate freely and conform their speed to the path they are taking. Turning up a steep hill may be aided by 4WD tho, but not as much as if they were turning fast enuf for the long path they take.
Larry

 

[Soundguy]

I propose that there is no evidence that such "increased" "measurable" wear exists when a tractor is driven in 4WD all the time on dirt, weather needed or not.Cheers!

I would think basic physics would show that there is extra measurable wear on a part under a load, vs a part not under a load.

Take 2 identical bearings, ( same lube, same gearbox ) run one freewheeled under no load.. run the other under varrying load conditions.. run them both the same # of thousand hours.. etc.. I can't see anything scientifically that would say the part under load would wear -LESS- than the part under no load... I just don't think you have any scientific basis to back that statement up.

It may take a piece of plastigauge or a micrometer , or gear surface/ bearing end play inspection to view this wear.. but I can't see anything that would say that the components under stress would not wear any more than the units not under the 'extra' stress.. etc.

I'm not saying 'undue' stress.. I'm not saying 'catastrophic failure'.. I'm saying the aprts run under extra stress will exhibit more wear.

Anyone ever notice that the driven front tires on a machine don't last as long as non driven ( non braked ) front tires ? ( tread.. not specifically casing life..)

Soundguy

 

[HomeBrew2]

Larry, when I sober up I'll re-read your post but, right now, I think we agree on all principles. Maybe that's what you were saying. Not sure.
Cheers!

 

[HomeBrew2]

Soundguy, Thanks for taking the bait. Usually my posts end the thread so I like to add an "impossible to justify" comment to keep it going. Of course you are right on all counts ... as long as we are using a mic

Now on more serious terms, given your back ground, have you ever seen premature failure of a front-end that was engaged all the time, as compared to one that was shifted in and out as needed? ... that was my real point ... and I know you realize that, but I appreciate your reply

 

[Soundguy]

Now on more serious terms, given your back ground, have you ever seen premature failure of a front-end that was engaged all the time, as compared to one that was shifted in and out as needed? ... that was my real point ... and I know you realize that, but I appreciate your reply

As was stated.. my post was not directed toward premature failure.. it was simply stating that extr awear accrues when using 4x4 full time vs shifting between the two.. nothing more.. nothing less.

Hard to chalk up a failure on any specific part to any specific cause.. unles you have an action that you can directly relate to a failure.. like.. ramming a pile with a loader bucket at full speed, then hearing a snap, and then seeing a bent bucket mount.. that's an example of a failure that is directly attributable to the previous action.

Bearing wear, normal or otherwise is harder to track. I have deffinately seen 4x4 components that were shelled out from driving on hard surfaces in short periods of time. But where do you point he blame without breaking it down for periodic measurement in comparison to a similar unit doing similar work.

Might have been a manufacturing defect.. like wrong bearing preload.. or any number of causes.

All I can say is that from an engineering standpoint, the more stress a part is under. the more it will wear compaired to a similar part not under that load.

Soundguy

 

[HomeBrew2]

As was stated..

Fair enough ... I think. You proposed my "absolute" statement was flawed but, you can only presume that your stance can be proved with a mic. I accept that it is possible to prove it that way. I see no contest ... unless you are willing to prove your point by performing an experiment, such as the one I performed that was proposed by the fellow that I was ACTUALLY responding to, and QUOTED.

I believe the context of this thread, and my reply, probably not withstanding my "baiting" punctuation, are in harmony. If you'd like to dwell on my single sensational comment, feel free to do so. I have plenty of time. The key issue , to me, is, is there any REAL reason to NOT to be in 4WD when on a non-paved/HIGH-traction surface. In my view, no one has provided ant evidence to that end, eventhough I performed the challenge to which I replied (and quoted).

Cheers!

 

[Soundguy]

Any real reason??.. I believe at least one good one has been posted. Sounds like 'torn up grass on a tight turn' seems to top the list.

That is, in context now, if you are on flat 'safe' land, .. not wet.. no hills.. no embankments or ditches... you could probably save some wear and tear on sod by disengaging 4x4.

that fit your test?

Soundguy

PS.. as for:

<unless you are willing to prove your point by performing an experiment>

Sure.. you go purchase 2 tractors, one locked in 4x4, and the other 2x4.. set them up to run on a test course for 2000 hours.

I already have the micrometer and plastigauge... and I'll pay for the front end oil anylisis that will likely show more metal content ( thus bearing and gear facing wear ) on the 4x4 unit. I'll also pay for a detailed surface inspection of the gear tooth facings, compaired with each other, and a third 'control' un-used gear.

The oil anylisis should show the metal content and we should be able to read that against a bearing wear table. We do this for our heavy equipment ALL the time instead of tearing half a million dollar machines down to just check the bearings... it's very telltale.

Side and end play, and gear backlash can be checked with a good set of feeler gauges. I can't help but expect the unit run in 4x4 for the 2000hr trial will show increased wear on bearing surfaces and/or gear tooth facings vs the unit not run in 2x4. etc..

Sound fair?

Soundguy

One other side note that is somewhat relevant.

Look at a diffy.. take 2 equal tractors. now put one different tire on one of the units rears.. run them around... would you expect to se more wear on
the diffy in the unit that had the unequal tires? I would.. and have seen it... that equates to extra workand stresses on that diffy vs a unit that was not recieving that extra work and stresses.