4WD Front to Rear Tire Ratios

[sixdogs]

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It has very very little pull or bind when running in 4wd. If running on hard surface it's just enough to cause it to not want to unlock. A seesaw of the steering wheel while moving unlocks it though.

Sometimes my Deere is a little tough to get out of FWA but that's typical. Accelerate and back off or shifting is usually what it takes for me. I know that you know to stay out of FWA while on hard ground but others reading this may not know. Best to stay out of FWA while on a hard surface because it will chew up the font tires and can damage the front axle. The last part I think I read in the owner's manual.

For people very aggressively using FWA with heavy slippage where a lot of wear is involved I have seen them mount the front tires with the tire pattern going backwards. It looks dumb but seems to work.

 

[ovrszd]

Oh yeah, sixdogs, I'm one of the guys usually cautioning about overuse of 4wd. If doing a variety of FEL work I may engage/disengage 4wd several dozen times in a day. I was simply referring to doing a 4wd task, then driving away on hard surface before remembering to disengage. Rather than stop/reverse/start again, I just seesaw the steering wheel a couple times and it disengages.

There are several TBN members that claim to rarely disengage their 4wd. For them this discussion about front to rear ratio is critically important. For them their tractors suffer additional stresses as they chew off the tread of their front tires (changing the ratio) and then again when they add new front tires against worn rears.

Does that mean their tractors are doomed to fail?? No. It's simply small things that can be done to extend the life of the tractor's powertrain. No different than sixdog's discussion above.

 

[rScotty]

Oh yeah, sixdogs, I'm one of the guys usually cautioning about overuse of 4wd. If doing a variety of FEL work I may engage/disengage 4wd several dozen times in a day. .

Same here. Agree completely.
We engage 4wd if the job requires it and then disengage it when it doesn't. I like to think that most everyone with the kind of 4wd found on the tractors in this forum does the same. On the M59, JD310, or the compact Yanmars the engage/disengage cycle can be as often as a dozen times an hour if doing a lot of loader work, because I'll engage it simply to avoid spinning the rears when pushing the loader into a pile....and disengage while turning around to take the load somewhere. On the other hand, I'd have no hesitation about leaving it in 4wd all day on snow or ice or sloppy clay mud if needed for pushing or pulling work without load in the bucket.
It's all about traction. If I forget and leave it in 4wd when pulling onto a high traction surface - like on pavement - then that's just an "aw shucks & forehead-slapping" kind of mistake. Hopefully we will "feel" that mistake through the steering wheel and of course then we slow down or stop to disengage the front axle. Although as you say, we do forget it some times and certainly we expect the tractor to be able to take a reasonable amount of that abuse without complaining. It would be a sad, surprising, and disappointing thing if it didn't. All of which doesn't stop it from being abuse, though. The same rules apply to the similar type of 4WD found on our Ford F250 PU, JD310, and the old '72 K10 Chevy PU.

Now the "going to town car"....which is a '97" Toyota Land Cruiser FJ80....is a different kind of animal altogether. It has a more modern and complicated All Wheel Drive (AWD) instead of the old 4WD we've been discussing. It's not just a difference in terminology, because its AWD has a center differential plus limited slip in the driveshaft between the fronts and rear axles. That enables it to stay in AWD mode all the time regardless of traction. There's not even a way to change out of AWD; no reason for it. That's modernization for you; the older 1985 FJ60 LandCruiser which preceeded it didn't have AWD. It worked like the more primitive tractors....or the modern Ford F250 PU.
luck, rScotty

 

[dragoneggs]

Oh yeah, sixdogs, I'm one of the guys usually cautioning about overuse of 4wd. If doing a variety of FEL work I may engage/disengage 4wd several dozen times in a day. I was simply referring to doing a 4wd task, then driving away on hard surface before remembering to disengage. Rather than stop/reverse/start again, I just seesaw the steering wheel a couple times and it disengages. There are several TBN members that claim to rarely disengage their 4wd. For them this discussion about front to rear ratio is critically important. For them their tractors suffer additional stresses as they chew off the tread of their front tires (changing the ratio) and then again when they add new front tires against worn rears. Does that mean their tractors are doomed to fail?? No. It's simply small things that can be done to extend the life of the tractor's powertrain. No different than sixdog's discussion above.

I am 'one of those' guys. I use my BX on a very sloped property (except for my big paved parking area in front of my house. I learned my lesson a couple of times forgetting to engage 4WD when starting out and heading down to get to work on terracing or burn piling, whatever and have scared the carp out of me. When I occasionally drive onto the pavement I always feel the bind and usually switch out if I am going to do much turning at all. It's easier for me to feel it than to remember before it's too late.

 

[ovrszd]

Now the "going to town car"....which is a '97" Toyota Land Cruiser FJ80....is a different kind of animal altogether. It has a more modern and complicated All Wheel Drive (AWD) instead of the old 4WD we've been discussing. It's not just a difference in terminology, because its AWD has a center differential plus limited slip in the driveshaft between the fronts and rear axles. That enables it to stay in AWD mode all the time regardless of traction. There's not even a way to change out of AWD; no reason for it. That's modernization for you; the older 1985 FJ60 LandCruiser which preceeded it didn't have AWD. It worked like the more primitive tractors....or the modern Ford F250 PU.
luck, rScotty

Scotty,

The wife's '11 Jeep Grand Cherokee is the same way. I'm a 4wd nut and don't own anything 2wd. I sat in that vehicle when she first got it with owners manual in my lap and went thru all the options and processes. Knowing fully well that my wife would struggle with the choices. When I was done I still did not think I fully understood the selections and what they did. Bout the time I was talking loudly to myself Terry opened the passenger door and got in, saying what'd ya figure out?? I closed the manual and said, see this knob with snow, auto, sand, blah, blah blah settings?? Always, always leave it in auto. That will take you anywhere you will be driving this vehicle. :confused3:

 

[ovrszd]

I am 'one of those' guys. I use my BX on a very sloped property (except for my big paved parking area in front of my house. I learned my lesson a couple of times forgetting to engage 4WD when starting out and heading down to get to work on terracing or burn piling, whatever and have scared the carp out of me. When I occasionally drive onto the pavement I always feel the bind and usually switch out if I am going to do much turning at all. It's easier for me to feel it than to remember before it's too late.

Yep, I understand that. When I'm in the timber, which is steep, I'm almost always in 4wd. But I'm also ballasted pretty heavy in the rear and if traction is good can back up some pretty steep terrain in 2wd.

 

[rScotty]

I am 'one of those' guys. I use my BX on a very sloped property (except for my big paved parking area in front of my house. I learned my lesson a couple of times forgetting to engage 4WD when starting out and heading down to get to work on terracing or burn piling, whatever and have scared the carp out of me. When I occasionally drive onto the pavement I always feel the bind and usually switch out if I am going to do much turning at all. It's easier for me to feel it than to remember before it's too late.

Are you talking about using the brakes when going downhill? That's sort of the same thing - but for a different reason. Many compact tractors have brake drums on the transmission countershaft instead of on the axle shafts. And unlike cars, compact tractors don't tend to have dedicated front wheel brakes at all.
The result being that in 2wd mode all tractors made like that will only brake the rear tires - which can sure create some excitement going downhill! Especially with a load in the bucket....
But because the brakes are on the countershaft, they are able to distribute the braking effort to all of the various axles and shafts which are directly connected to the transmission. When you engage 4wd that includes the fronts....at least a little bit.
What was a problem has now become a virtue...
rScotty

 

[dragoneggs]

Are you talking about using the brakes when going downhill? That's sort of the same thing - but for a different reason. Many compact tractors have brake drums on the transmission countershaft instead of on the axle shafts. And unlike cars, compact tractors don't tend to have dedicated front wheel brakes at all. The result being that in 2wd mode all tractors made like that will only brake the rear tires - which can sure create some excitement going downhill! Especially with a load in the bucket.... But because the brakes are on the countershaft, they are able to distribute the braking effort to all of the various axles and shafts which are directly connected to the transmission. When you engage 4wd that includes the fronts....at least a little bit. What was a problem has now become a virtue... rScotty

I honestly haven't looked at the brake design on mine. If I don't engage the 4WD going downhill in one section, I start hopping and there is nothing I can do to stop, brakes make it worse. Having the front wheel in gear provides the braking I need I guess.

 

[ovrszd]

I honestly haven't looked at the brake design on mine. If I don't engage the 4WD going downhill in one section, I start hopping and there is nothing I can do to stop, brakes make it worse. Having the front wheel in gear provides the braking I need I guess.

Yeah, that hopping down the hill is not a good feeling. Really doesn't matter where in the driveline the brake application happens as long as it only affects the rear axle. When in 2wd applying the brakes going down a hill will only slide the rear tires. When in 4wd the rear axle and front axle rotate at the same approximate speed. So brakes applied to the rear axle will also slow or stop the front axle. So braking is dramatically improved.

Funny side note. When sliding down a hill in 2wd all that's required to reduce or stop movement is to drop the FEL bucket. But in the panic of it all, a guy never thinks to do that.

 

[rgmosley]

Richard, Here is a picture of my rear axle on my 3910. The axle diameter is 5.5" and the wheel fits the flange very tight.



Thanks, Bob