Brake set up & differential

al m · Nov 18, 2017

Does the manner I witch the brakes are set up affect the performance of the differential? Put about 5 hours on my b1750 today grading topsoil,and noticed the power is almost always on the right hand wheel, and the differential is not as easily manipulated as with other tractors I have had.I am a thinking a quick tap of the brake should transfer power to the opposite wheel,but I pretty much have to stay on the brake to keep it there.

Rosher18 · Nov 19, 2017

Re: Brake set up &amp; differential

Tire pressure can affect the grip each tire has. The differential sends equal torque to each rear tire when unlocked. If one has less grip than the other, that one will spin earlier than the other. The maximum torque the tractor can put to the ground is then limited by the tire with the least grip. In your case, the right tire begins to slip at a certain torque value, and the differential sends the same amount of torque to the left tire.

Low pressure generally increases contact patch and grip. Slight elevation differences across the tractor (side-to-side) will also lead to a similar situation.

What do you mean when you say you should be able to "tap the pedal to switch power to the other wheel?"

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al m · Nov 19, 2017

First off,as a teen I spent literally thousands of hours in the seat , as a cash cropper,,100pluss hp. If I was In Trouble, as In starting to loose traction,I would tap the brake on the wheel that was spinning,thereby transferring powered to the opposite wheel,was a operator that pulled through,or buried the machine from there on( as well as feathering the impliment,be it in th three point,or the remoteness,or both.

Rosher18 · Nov 19, 2017

al m said:
First off,as a teen I spent literally thousands of hours in the seat , as a cash cropper,,100pluss hp. If I was In Trouble, as In starting to loose traction,I would tap the brake on the wheel that was spinning,thereby transferring powered to the opposite wheel,was a operator that pulled through,or buried the machine from there on( as well as feathering the impliment,be it in th three point,or the remoteness,or both.

Alright, I apologize if I seemed condescending. We have a huge range of experience levels on this site, so we try to start basic and draw out more information to get the correct answer.

I have done the same thing with regards to tapping a name to reduce the spinning and get more power delivered to the not-stuck wheel.

Maybe the tires are worn unevenly? It would help us figure out the issue or answer your question if we had more information.

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torch · Nov 20, 2017

A perfect, theoretical, differential applies exactly equal torque to each wheel. However, in the real world an open differential has a slight bias to one side or the other due to torque reaction from the driveshaft and ring gear -- the rotational force torques the vehicle slightly to one side, applying downward force on that wheel and upward force on the other. So given identical surface friction on both wheels, the one with less weight will have a tendency to break free first if the available torque exceeds the available friction.

It was quite commonly observable in the days of big rear-wheel drive cars any time snow or ice were encountered. The right rear would usually break free first in forward, the left rear would break free in reverse (because the driveshaft spins in the opposite direction in reverse).

Maybe that's what is going on here?

al m · Nov 20, 2017

Rosher18 said:
Alright, I apologize if I seemed condescending. We have a huge range of experience levels on this site, so we try to start basic and draw out more information to get the correct answer.

I have done the same thing with regards to tapping a name to reduce the spinning and get more power delivered to the not-stuck wheel.

Maybe the tires are worn unevenly? It would help us figure out the issue or answer your question if we had more information.

Sent from my VS986 using Tapatalk

No apologies needed,I'm sorry if I made it seem like there was reason.
Just wondering if a brake adjustment is wise,the pedals feel different,and are not at the same height ,guess I should have said that right off.
Thanks for the reply,I appreciate it

al m · Nov 20, 2017

torch said:
A perfect, theoretical, differential applies exactly equal torque to each wheel. However, in the real world an open differential has a slight bias to one side or the other due to torque reaction from the driveshaft and ring gear -- the rotational force torques the vehicle slightly to one side, applying downward force on that wheel and upward force on the other. So given identical surface friction on both wheels, the one with less weight will have a tendency to break free first if the available torque exceeds the available friction.

It was quite commonly observable in the days of big rear-wheel drive cars any time snow or ice were encountered. The right rear would usually break free first in forward, the left rear would break free in reverse (because the driveshaft spins in the opposite direction in reverse).

Maybe that's what is going on here?

Makes sense,still wonder

Rosher18 · Nov 20, 2017

torch said:
A perfect, theoretical, differential applies exactly equal torque to each wheel. However, in the real world an open differential has a slight bias to one side or the other due to torque reaction from the driveshaft and ring gear -- the rotational force torques the vehicle slightly to one side, applying downward force on that wheel and upward force on the other. So given identical surface friction on both wheels, the one with less weight will have a tendency to break free first if the available torque exceeds the available friction.

It was quite commonly observable in the days of big rear-wheel drive cars any time snow or ice were encountered. The right rear would usually break free first in forward, the left rear would break free in reverse (because the driveshaft spins in the opposite direction in reverse).

Maybe that's what is going on here?

That's a fair possibility as well. I hadn't considered that because of how much more rigid tractors seem to be than cars or trucks.

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Rosher18 · Nov 20, 2017

No harm no foul. I was tired and selected the first meaning my mind read, and clearly it was off the mark.

The pedals sitting unevenly intrigues me. If you were to push them both down when latched together, do both

al m said:
No apologies needed,I'm sorry if I made it seem like there was reason.
Just wondering if a brake adjustment is wise,the pedals feel different,and are not at the same height ,guess I should have said that right off.
Thanks for the reply,I appreciate it

No harm no foul. I was tired and selected the first meaning my mind read, and clearly it was off the mark.

The pedals sitting unevenly intrigues me. If you were to push them both down when unlatched from each other, do they both hit resistance at the same position, relative to each other?

On my L185DT, if unlatched my right brake pedal sits a bit higher than the left, but they seem to engage at the same relative height and the tractor doesn't pull one way or the other when stopping at speed.

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Brake set up & differential

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