[Jonathan]

If my tractor converts the RPM's to 540, what does the mower deck gear box convert them too?

 

[OldBuzzard]

I'm not sure about the Isiki Bolens, but all of the others have 2000 RPM PTOs, and the mower gearboxes are designed to use that RPM.

If you try to run one with 540 RPM, the blade speed will be WAY too low.