Tractor Sizing Tractor pto for 7 foot cutter

[Bigfoot62]

Bigfoot62 seems to contradict t his theory if he's comparing a 7' single spindle to a 10' twin spindle cutter, and the 7' model taxes the engine more.

I'm not as smart as TexasMark, and I can't give you the formulas, but I know from experience that a single spindle 7' pulls harder on the tractor than the twin spindle 10". I've run both cutters behind my 70hp, my 85hp, and the 100hp tractor that I had before. Same results on all three tractors.

 

[Bigfoot62]

For what it's worth, I have an 8 ft dual blade Ford (old school) brushog ... and my Massey 1648 hydro (36.5 PTO HP) has no problem with it. . .

Yessir. But, I'll bet that your little tractor would choke in deep grass with a 7' single, IF it could even pick it up!

 

[Tx Jim]

For what it's worth, I have an 8 ft dual blade Ford (old school) brushog ... and my Massey 1648 hydro (36.5 PTO HP) has no problem with it.

One reason your 36.5 pto HP tractor can easily handle your 8' mower is because it's belt on gear box driven.

 

[TSO]

One reason your 36.5 pto HP tractor can easily handle your 8' mower is because it's belt on gear box driven.

Yessir. But, I'll bet that your little tractor would choke in deep grass with a 7' single, IF it could even pick it up!

Yes, well ... whatever the reason is that my little tractor can easily handle this bhog, the point is that it does. So if the OP wants a large bhog, he can consider a twin blade belt driven one without needing 80 HP

 

[Fallon]

Why would a bet drive be any better than a gear drive? Belt isn't that different than gear, chain or shaft in terms of efficiency.

 

[GManBart]

One reason your 36.5 pto HP tractor can easily handle your 8' mower is because it's belt on gear box driven.

That doesn't change the weight of the blades, or the resistance of what's being cut. There could also be more power loss in the belt system compared with shaft drive setups....and a belt drive would have less inertia due to lower mass connected to the blades.

Regardless of all that, and hypothetical theory aside, lots of people have compared 7' single spindle to 8' (and larger) twin-spindle, and the consensus is the dual spindle setups take less power to run properly. Calculate all you want, it isn't changing actual results folks are reporting.

 

[Gary Fowler]

For what it's worth, I have an 8 ft dual blade Ford (old school) brushog ... and my Massey 1648 hydro (36.5 PTO HP) has no problem with it.



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Tall weeds are much easier to cut than tall grass. If you want to see how much power is needed, run thru some tall Bahia grass to load you up. I am thinking this is one reason for so many varied answers. Some folks just cut tall weedy stuff that produces a lot of bulk but very easy to cut so not much HP needed. Others may be cutting tough stringy grass and tough weeds that need a lot of HP to pull thru. My lawnmower runs 5 HP per foot as per suggested bushhog requirements and in heavy grass it needs all that and then some. YMMV

I don't doubt that some dual spindle cutters take less HP to turn in same conditions as owners have posted

 

[TnWV]

I run an 8' dual spindle cutter with a 56 PTO HP Zetor. It could certainly run on less HP, but as others have said, pay attention to weight. Mine weighs 1550 lbs according to the manual, and while I've never ran out of power, I'm glad I have a pretty heavy tractor. You don't want the mower pushing you around if you have hills to mow. I also believe a pull behind requires a little less HP than a 3-point model as well. That said I have no problems with either on my tractor. I don't know how the tractors your looking at compare in size and weight, but here are some pictures of mine for your reference.

 

[TSO]

I run an 8' dual spindle cutter with a 56 PTO HP Zetor. It could certainly run on less HP, but as others have said, pay attention to weight. Mine weighs 1550 lbs according to the manual, and while I've never ran out of power, I'm glad I have a pretty heavy tractor. You don't want the mower pushing you around if you have hills to mow. I also believe a pull behind requires a little less HP than a 3-point model as well. That said I have no problems with either on my tractor. I don't know how the tractors your looking at compare in size and weight, but here are some pictures of mine for your reference.

Nice mower ... but I can't imagine that a 3pt model would require more HP to run than a pull behind one.

 

[GManBart]

Nice mower ... but I can't imagine that a 3pt model would require more HP to run than a pull behind one.

Bush hog calls for 10hp less on the pull model 8' compared with the 3pt lift that is otherwise the same:

2008 Series Rotary Cutters