ArtVandelay said:
What is the minimum PTO required for a 6ft Bush Hog?
It's all about what you'll be mowing. Heavy grass about knee deep can be the toughest thing to cut. "Brush" can run the gammit from dry scrub to heavy, woody thickets. With that in mind, brush can be relatively easy to cut, or it can be slow going, tough cutting, and rough on equipment. The toughest single thing to mow I've ever encountered is a thick stand of bermuda grass about waist high. That'll bog down a 60hp tractor pulling a 6' mower.
For clipping pastures that are relatively well maintained, 25 or 30 hp will suffice for a 6'er. Tractor HP and that tractors ability to handle weight are somewhat related. Not as a carved in stone figure, but more as a general rule of thumb, the less the hp, the smaller the tractor, the lighter the hitch capacity. Or at least, smaller HP tractors tend to be lighter which limits a tractors ability to handle a heavy mounted implement. Medium and heavy duty mowers weigh more than light duty as you might imagine. As the weight goes up, the need for a tractor that can handle that weight goes up accordingly. So.... as the mower's "duty rating" increases, so does the need for a bigger tractor. With that bigger tractor, the hp number USUALLY increases right along with size.
Some consideration has to be taken for what ground speed you intend to mow at also. Conditions will dictate that limitation. Flat, smooth, obstruction free fields and you can set sail with enough power. Lower HP means slower speeds even if conditions would allow higher ground speed.
I use a 6' medium duty Bush Hog 286 on a 47 PTO HP tractor. In 90% of the situations I use it, that's more than adaquate. But I've mowed a few places where 47 hp is barely enough.
Again, it all depends on what you're mowing.