Is it possible for a tractor to have limited slip?

[k0ua]

My first experience was in 1964 when I purchased a posi unit and put it in my 1964 Chevelle. The unit cost me a grand total of $44 plus a couple bucks for 2 quarts of the good lube that was made in those days. Let's hear it for inflation. GM brought out the posi unit in 1957, mainly for the highly successful Corvette and the new fuel injection systems that came out that same year for Chevy and Pontiac.

Thanks for the info, I know by the end of 1960's the posi units were quite common, although they had their limitations. I have the Eaton G80 unit in my new Chevy pickup, I have heard some good and bad comments on this unit. Do you have any thoughts on this type of locker?

It also has the traction control, where it brakes the wheel that is spinning and reduces engine power, I dont know if this works for the front wheels or not when in 4 wheel, I dont see why it couldnt but it may not. does anyone know?

James K0UA

 

[EE_Bota]

that is why in your owners manual of your car, they caution against "excessive" wheel spin as it is hard on your spinning tires to go that fast, as you can easily go over the speed rating of your tire, and it can fly apart.
James K0UA

Sounds to me that's why it says it in your owner's manual. In my owner's manual, they substituted a paragraph about bailing out safely if the car gets possessed by an evil spirit.

I never was much of a hot-rodder, so if it says that in my manual, it's to keep me from spilling my coffee on my shirt if a tire spins a cow patty.

Edit: Direct quote from my manual: "If you feel there is a danger the wheel will disintegrate, and you are sober, the HAL 9000 engine control module is self-aware, and despite advice from the HAL 9000 unit, it is time to exit the vehicle, regardless of speed."

 

[TripleR]

Sounds to me that's why it says it in your own's manual. In my owners manual, they substituted a paragraph about bailing out safely if the car gets possessed by an evil spirit.

I never was much of a hot-rodder, so if it says that in my manual, it's to keep me from spilling my coffee on my shirt if a tire spins a cow patty.

Edit: Direct quote from my manual: "If you feel there is a danger the wheel will disintegrate, and you are sober, the HAL 9000 engine control module is self-aware, and despite advice from the HAL 9000 unit, it is time to exit the vehicle, regardless of speed."

:laughing::laughing::laughing::laughing::laughing:

 

[Bird]

I really hadn't thought much about whether any tractors have limited slip differentials, since my Kubotas had the common differential lock pedal. But going back to the middle ages when we had a 1940 John Deere L, I can remember a number of times I tried pulling something it couldn't move, but the rear tires would dig holes in the ground and they never spun together. One would turn aways, stop, and the other one would turn a short distance, and stop; just back and forth, so I assume it must have had some kind of limited slip. And of course, the tractor would rock back and forth when it was doing it.

 

[dcyrilc]

I really hadn't thought much about whether any tractors have limited slip differentials, since my Kubotas had the common differential lock pedal. But going back to the middle ages when we had a 1940 John Deere L, I can remember a number of times I tried pulling something it couldn't move, but the rear tires would dig holes in the ground and they never spun together. One would turn aways, stop, and the other one would turn a short distance, and stop; just back and forth, so I assume it must have had some kind of limited slip. And of course, the tractor would rock back and forth when it was doing it.

I had both rears and both fronts going at the same time with the tractor walking back and forth sideways. It's possible that it was due to limited traction, but I would think that once I started throwing the gravel and with the duels on that it would be hard to have the lack of traction equal and keep it that way.

 

[V1Rotate]

I really hadn't thought much about whether any tractors have limited slip differentials, since my Kubotas had the common differential lock pedal. But going back to the middle ages when we had a 1940 John Deere L, I can remember a number of times I tried pulling something it couldn't move, but the rear tires would dig holes in the ground and they never spun together. One would turn aways, stop, and the other one would turn a short distance, and stop; just back and forth, so I assume it must have had some kind of limited slip. And of course, the tractor would rock back and forth when it was doing it.

With an open differential the tire with the least amount of traction will spin. I think what may have been happening to you is that after one tire had been spinning for a bit, it would gain some traction and stop spinning. The other tire would start to spin because it now had less traction than the first tire.
This process then continued.

 

[Bird]

With an open differential the tire with the least amount of traction will spin. I think what may have been happening to you is that after one tire had been spinning for a bit, it would gain some traction and stop spinning. The other tire would start to spin because it now had less traction than the first tire.
This process then continued.

I'd say that's entirely possible. It was kinda of like a dog digging in the ground with first the right paw, then the left, and keep on alternating.

 

[Bird]

be hard to have the lack of traction equal and keep it that way

I agree, but I guess it would be possible.

 

[EE_Bota]

Here is my best guess:

Sometimes I wonder if your issue boils down to "why didn't I get stuck?"

What I mean by that is:

In any case that the tractor is not stationary, you are not stuck.

In any case you are not stuck, all wheels are turning, even if the tractor is just skidding sideways.

In any case you ARE stationary, but the traction difference is not great enough side to side, all wheels on that axle will be turning.

If the rears are doing this, in all cases where the traction is unequal in the rear, a moment is applied that has to be countered by the steering wheels, and in some of those cases the moment may not be countered effectively, causing the front wheels to slide, making it unlikely either front wheel can stop.

It could be that if each side is slinging and shearing different material, one side speeds up and the other slows down, but only in proportion to how hard each material is to sling and shear. Wheel stoppage can be thought of as the upper bound of the range of speeds two wheels encountering variable resistance can assume.

A four wheel drive tractor just seems to be more dynamic than a two wheel drive. Even on dry soil, the fronts run a slightly different speed, and one axle is more dynamic than the other, and which axle that is varies continuously during a mud rodeo event like you described.

This has been a great topic. The only way it would be better is if you went out and did it again just to film it for us.

Edit: Would it be true to say: In an open differential, for most practical purposes, the average torque on each wheel is the same, and the average power is the same, except in the case of the wheel stopping, when power goes to zero? So the rpm varies from side to side except in the special case.
.

 

[dcyrilc]

This has been a great topic. The only way it would be better is if you went out and did it again just to film it for us.

.

Hmmmm.................

...my daughter did just get a digital video camera for Christmas.

But then with my luck, I'd pull the trailer part way out to try to get another shot at it and not be able to even get it back to where it is now. Maybe I should stay quit while I'm ahead.:laughing: