Mowing brush hog vs finish mower

StableBoy · Dec 23, 2004

Is there a general rule about which one requires more HP to operate (assuming identical widths) in tall grass?

RoyJackson · Dec 23, 2004

The brush cutter needs more horsepower...that's a fact. They generally weight about 200 lbs. more the same sized finishing mower.
Of course, the intended purpose of the cutter is to work in areas that have tall grasses or brush...that would tear a finishing mower up pretty quick.

The rule of thumb I've read on TBN (and my dealer concurs) is 5 HP per foot of cutter width. Now, I've never heard it expressed as PTO HP or Engine Gross HP.

As far as finishing mowers...never hear any specific requirements, other then that which is recommended by the implement manufacturer.

That said...I run a 5' cutter through moderate to heavy brush (and saplings) with a 24 PTO HP Deere 790. That's 4.8 PTO HP per foot and it works mighty fine. However, I used that same 5' cutter behind a Deere 670 (16.5 PTO HP) which also did fine. That's 3.3 PTO HP per foot.
The 790 does handle the work better, but the 670 did a heck of a job. That cutter, per Land Pride, should be ran behind a 20 HP (minimum) tractor. Land Pride doesn't specify PTO or Gross HP, but I'm assuming they mean PTO HP.

As far as finishing mowers...I figure if the PTO can pick it up, the tractor can run it. I'm using a 5' mower currently. I could easily run a 6' mower...I'd even consider a 7" mower if it didn't overload the 3PH capacity. Of course, I don't have the $$$ for a bigger mower, but I know the tractor can handle more then I've got now.

mrolson · Dec 23, 2004

My bush hog is direct driven off the gear box while my finish mower is belt driven off the gear box. There is a huge loss of HP through the belt and requires more HP to get the same job done.

teddydo · Dec 23, 2004

Roy J, I have a 6 foot finishing mower. I pulled it with a 600 Ford for years but in thick grass, not weeds it was all the Tractor could pull and would bog down at times. I now pull it with a 4330 Kubato and it don't seem to know it's behind it. So in my opinion a finishing mower it just as difficult if not more difficult than a brush cutter to pull. Once that one big blade gets spinning on a brush cutter it's just hard to slow down. Those three small blades spinning under my finishing mow just don't have the counter weight effect as the brush cutter. Your assesment of the HP per foot sounds like a good rule of thumb. Another thing to take into consideration is my finishing mower is set much lower than the brush cutter. Just sounding off a little......Merry Christmas.....Teddy /forums/images/graemlins/laugh.gif

Tom_H · Dec 23, 2004

( Once that one big blade gets spinning on a brush cutter it's just hard to slow down.)

I have to agree with that. The blade builds a high level of kinetic energy by the formula Kinetic Energy = Mass x Velocity. There are actually 2 blades attached at pivot points to a rotating pan. If a blade does hit something capable of absorbing all that inertia, the blade simply pivots and slides off, ready for the blade on the opposite side to take another swordlike chop at the obstacle.

The finish mower is designed to give a smooth cut to turf. Its little blades are not designed to overcome resistance. If you hit something with high stationary inertia, the blade, having a low amount of kinetic energy and not being able to swivel, simply stops which stalls the engine.

Comparing these implements to each other is like comparing hair trimming scissors to a machete or meat cleaver. They are for completely different purposes. You could use the RFM in rough stuff, but you certianly will not get optimum results.

mrolson · Dec 23, 2004

When ya kill the PTO on a brush hog vs. a FM., how much longer do the blades spin on the cutter... Its not the size or weight of the blade, its the drive. Belts eat HP.

And I agree its like comparing apples and oranges. Two different tools for different jobs.

RoyJackson · Dec 23, 2004

My RFM winds down quickly...the cutter spins for 60 seconds or so...

Maybe the belt eats HP, but the cutter is built to go through much thicker, heavier stuff....and I've never had my mower
bog the tractor down. The cutter does, occasionally. Of course, I'm mowing a finished lawn with the mower...at worst, 5" tall. I wouldn't even use a finishing mower on grasses much taller or thicker then a lawn...not built for that kind of work.

Take a look at the manufacturer's reccomendations...see what you find...

teddydo · Dec 23, 2004

Stable boy, Hands down in my opinion the finishing mower is most difficult to pull and eats up more HP. I've used both. Just my opinion and I respect the others. Maybe I am going to learn something here I know I need to. Each are for different tasks but are similar and I think they can be compared. Merry Christmas /forums/images/graemlins/laugh.gif Teddy

DmansPadge · Dec 23, 2004

( The brush cutter needs more horsepower...that's a fact. They generally weight about 200 lbs. more the same sized finishing mower.)

Not trying to start anything here... but I would agree with others that a belt driven FM would require more HP. But like you say... a BH is used for rough cutting taller/larger stuff and the FM is used for a smooth cut and not designed to handle what a BH can. So I think it would depend a lot on what you are using and what you are using it on.

( The rule of thumb I've read on TBN (and my dealer concurs) is 5 HP per foot of cutter width. Now, I've never heard it expressed as PTO HP or Engine Gross HP.)

I "thought" is was 3 PTO hp per foot but very well might be wrong. I recently bought a B7300 that is 16hp and 12.5 PTO hp. I am looking to buy a 4ft brush hog. It is supposed to be able to run a 4ft brush hog and the math works out that only 12 PTO hp would be needed to do so. I can't imagine that it wouldn't run a 4ft hog. If it was 5 PTO hp thats needed it would be rendered useless for mowing as I don't think you're going to find a 2' hog! /forums/images/graemlins/cool.gif 5 engine hp per foot would be closer but even at that rate my tractor still wouldn't pull a 4ft. All that said... I think 3 PTO hp per foot is a good figure to work from.

Just my opinion! Merry Christmas everyone! /forums/images/graemlins/cool.gif

DK35vince · Dec 23, 2004

( 5 engine hp per foot would be closer but even at that rate my tractor still wouldn't pull a 4ft. All that said... I think 3 PTO hp per foot is a good figure to work from.
)

I think you could run a brush mower with 3 HP per foot, but you won't be mowing very fast.
If you want to mow with any speed at all I would want at least close to 5HP/foot minimum
Just my opinion