A suicide knob is great if you have a tractor with power steering. Easy breezy turns and speedy maneuvering of the steering wheel.
If you have a tractor with old school manual steering, I would stay away from one. Your wrist and hand will thank you.
The steering wheel tends to rotate quite frequently on a tractor without power steering with a fair amount of force, as you encounter dips and bumps in your travel.
Add a suicide knob to that swinging and it beats the tar out of anything that comes in contact with it. And it's unforgiving.
I will say, if you decide to install a suicide knob, be wary of what your wearing as you go to get off the tractor.
I was operating one with a suicide knob and wearing carpenter jeans with the hammer loop. As I was getting off the tractor and just stepping down I hung the loop on the suicide knob.
This caused me to get hung with my feet off the steps suspended by the hammer loop, and a receiving massive atomic wedgey to boot