Tractor Sizing How important is rear diff lock on CUT?

[onelostdogg]

I had to use the Diff. lock on my LS once when crossing a deep ditch on an angle. One front and one rear ended up off the ground and I had no traction at all. The diff lock got me off high center and I was able to continue on across the ditch without resorting to using the FEL to push myself backward.

Exactly my situation on several occasions now. Living on a slope I have finally learned what I was taught in school. Water follows gravity. Don't have time or interest in controlling the entire 8 acres of drainage.

 

[AxleHub]

Perhaps we should look at it this way.
"Every well designed tractor has a diff lock feature to increase the tractor's ability and from that it's marketability. " So any tractor designed without it was designed by fools that don't know or care about how tractors are used in the fields. If they screwed up on this commonly understood point what else in the tractors design did they not understand or cut corners on??:duh:

I'm sad to say that sometimes a good manufacturer follows poorly informed customers.

Take Yanmar . . A great manufacturer. They had built the sc2400 which was very competitive in features and engine to kubota back in 06 and 07 etc.. as of this spring when I was looking new sc2400 were still available and I considered them.

Then Yanmar wants to update and recreate another winner. Logical. So they survey piles of propsects and some current clients to design the tractor of the new breed.

Prospects and some clients input is a diff isn't needed. So the 221 has no diff. Prospects and clients say multiple speeds aren't required . . So the 221 is a single speed. Prospects and clients say 2 pedals instead of treadle and leave the brake where it is . . So the 221 gas separate pedals . . Good . . . But brake is now worse because treadle was lower than pedals.

Yanmar should have listened less and designed the way THEY know how. 221 is nice but not what it should have been.

 

[k0ua]

It will go if you have split brakes

Yep, and with my split brakes on the left, where they belong on a HST machine, (in my humble opinion) they are super easy to use without any gymnastics, and highly effective. I wind up using them more than Diff lock is a ditch crossing scenario. but use what works for you would be my advice.

 

[LD1]

Agreed. Use what works best for each person. But saying a diff lock is the only way to get moving if a wheel is in the air is just false

 

[Grandad4]

It will go if you have split brakes

Good observation!

 

[AxleHub]

Could some one explain what split brakes are and how they work? It sounds as if you are fighting the engine or having some type of clutch engaged in order to get a differential lock type effort.

 

[jonnmero]

Could some one explain what split brakes are and how they work? It sounds as if you are fighting the engine or having some type of clutch engaged in order to get a differential lock type effort.

Split brakes is a system made to ensure that your tractor tips over when applied during a turn at (for a tractor) high speed:cool2:

 

[Grandad4]

Could some one explain what split brakes are and how they work? It sounds as if you are fighting the engine or having some type of clutch engaged in order to get a differential lock type effort.

Farm tractors typically have two foot pedals for the rear brakes, one for each side. They were originally used to allow farmers to make a "turn on a dime" turn at the end of a row by stopping just one of the rear wheels around which the tractor would pivot. There was a locking bar that could be engaged so the two pedals could be joined when the operator wanted both brakes working together for stopping. Farmers soon figured out that the split brakes were also handy when their 2wd tractors got stuck with one wheel spinning in mud, etc. By applying the brake to the spinning wheel, the differential would start supplying power to the other wheel, which was possibly on more solid ground. Presto! An early version of a locking differential.

 

[LD1]

Good explination.

Works almost the same way a GM gov-lock works. Only manually. The way a gov lock works is when one wheel starts spinning, a friction plate inside the rear end starts applying pressure to slow down that spinning tire, which applys more torque to the other wheel.

By definition, an open differential means EQUAL torque is applied to both wheels at all times, but can be unequal speeds. So a wheel in the air or on ice may only take 1 ft-lb of torque to spin. That means the wheel on solid ground is only geting 1ft-lb as well. Which isnt enough to move the tractor.

By applying the brake, it takes MORE torque to spin the wheel in the air or on ice. Therefore the wheel on solid ground is also getting more torque. how much more depends on how hard you press the brake on the opposite tire.

I cross uneven ground all the time and get hung up quire frequently with a wheel in the air. Its almost a natural reaction to hit the brake on that side and move on.

 

[k0ua]

I cross uneven ground all the time and get hung up quire frequently with a wheel in the air. Its almost a natural reaction to hit the brake on that side and move on.

Exactly. Once you get used to using them, it seems more natural to use that to get unstuck in many instances than the differential lock. Split brakes are also very useful for some other scenario's. Here are a couple.
Lets say you are working dirt right up against a foundation, and lets say it is on a slope, and need to maintain your "line" of travel. Often it is advantages to "skew" or "slew" the tractor slightly by using your appropriate split brake to stay close to that foundation as your dirt-working tool maybe attempts to move you away.

Another is scraping snow and ice on a slope with your blade applying pressure on the tractor to go "downhill" on that slope. Again judicious use of the appropriate split brake can get you back in a straight line when the steering wheel wont.

Now I am not say you throw in "hard right rudder captain!" I am just saying barely touching the correct brake to hold your steering line in the presence of other forces that are trying to push you off of your intended path.

Of course the original purpose of the split brakes to make hairpin turns by pressing one of them very hard is still a valid use, as well as the above purpose to get unstuck out of a mud-hole or a ditch crossing.

Of course the caution one poster posted about losing control by pressing one brake hard while zipping down the road applies. Just don't be stupid, don't do that. When roading a tractor, always pin the split brakes together with the bar the manufacture provided for that purpose.

Tractors are wonderful, and safe tools when operated as intended, of course if you really want to kill yourself with one, you can do that.