A lot of people use them to steer in the snow with a blower or blade. Some use them when using a lot of pressure on the FEL while back dragging. Others use them on slopes or to make very sharp turns. My cruise control will not disengage unless both brakes are applied, so you can use it with the "steering brakes".
John Deere and some other makes come with "steering brakes" on the left side, so you can use your HST pedal and the brakes while Kubota retains them on the right.
I grew up farming and used split brakes on the turn rows to minimize the room needed to turn around and maximize the length of rows. I also used to tap one side or the other to redirect traction as our tractors did not have diff lock back then.
There are a lot of uses, for split brakes/steering brakes.
Having said that, I personally rarely use them on my HST
L5030. I do use them on our M8540 as we use it a bit differently than the
L5030 and it won't turn as sharp with the steering wheel as the
L5030 being a bigger tractor.
This is often a hotly debated issue and I have been essentially told I didn't know what I was talking about, so keep that in mind.
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