Brush cutter size for a given horsepower

[Soundguy]

The old Farmall C can run a 5' cutter pretty well under most circumstances...loads the engine well in very tall grass but overall doesn't lug the tractor. When you consider that it is only rated at about 18 horsepower that's pretty good.
.

A C should have a 113ci engine.

A ford N has a 120ci engine.

N pull a 5' mower decent. The C should be right there close.. and it should be closer to about 23 hp.

 

[oosik]

Thanks LD1,

I feel its conservative also. I've found from experience ( sometime bitter - read as expensive) that light weight and even some medium weight implements do not fare well out here. I'm the furthest thing from abusive when it comes to equipment, too. It just really ticks me off that I have to treat a new implement like its made of eggshells. I've had implements bend, twist & knot-up with the best of them.

Actually, if & when I do buy a rear cutter I'll probably stick to a HD 60" cutter. I've got no big open fields to mow - just a lot of stabbing, poking and working around big pine trees, bedrock outcrops and the like. Many times its taken me over three entire days to walk and clear a small field just so I can carefully use an implement. Thanks for your insight and again, my apologies to the OP.

 

[Gary Fowler]

The rule of thumb is just that, I used to pull a 6 foot trailer type bush hog with an 8N just clipping the pasture of weeds. If you try to mow tall grass, you may not make it even in 1st gear while taking a full 6 foot swath. My LS P7010 (65PTO HP?) can stall a bit in tall grass with my 7 foot mower when I am in M 4 range but slowing it down to M1 or 2 usually cures the loading up problem. The previous owner of my B26 (26 Engine HP) pulled a 5 foot cutter with it in heavy mowing but I don't know how fast he was going.

So it is possible to dispute the 5 HP per foot rule on either side of the high/low HP requirement. I would still go with the widest BH that your tractor can handle on the 3 PH. You can always overlap in heavy cover but have the luxury of taking a full path in light stuff so your mowing gets done faster.

 

[C4Ranch]

LD1,

Very insightful comments. Its not my intention to steal this thread but I do have a question. My M6040 is rated at 55 pto hp and max rotary cutter weight of 1200 pounds. The horns of my dilemma are - I want a heavy duty cutter but the weight limitations of the 3-point will not allow for anything much over 60". The pto hp would allow for a much larger cutter than the weight limitation of the 3-point recommends. My rear tread width is 80".

What are the thoughts on going over the recommended 3-point weight limitations? My apologies to the OP on this question.

You can do more than that. I'm running a LandPride 8' twin spindle 3pt that's 1,400#s with my 45hp pto L series.

 

[Navasot]

I run a 7ft Mohawk HD DTW on a Massey 1540.... it don't like picking it up lol but will run the mess outa it

 

[LD1]

The rule of thumb is just that, I used to pull a 6 foot trailer type bush hog with an 8N just clipping the pasture of weeds. If you try to mow tall grass, you may not make it even in 1st gear while taking a full 6 foot swath.

Worth mentioning again, about tractor gearing.

Going big as I mention may not be as easy to apply on older tractors. An 8n has a 1st gear that is FASTER than my 4th gear. So not always the luxury of slowing down. Still can take smaller bites, but thats about it.

Modern tractors that have 1st gear in the 1MPH range, Can go a whole lot bigger than 5HP per ft.

I think 5 HP per ft is good for ~4-5MPH under light to medium conditions. And 5hp per ft @ 2.5-3MPH for the really thick stuff.

5 HP per ft @ 3MPH should pull the same as 2.5HP/ft at 1.5MPH. 8n's wont go that slow. Most modern CUT's will. And while HST robbs PTO power, you can go infinitely slow as needed.

 

[Soundguy]

Yup, n gears were tall..

 

[Navasot]

same with an old harris to30:shocked:

 

[RedNeckRacin]

The rule of thumb is just that, I used to pull a 6 foot trailer type bush hog with an 8N just clipping the pasture of weeds. If you try to mow tall grass, you may not make it even in 1st gear while taking a full 6 foot swath. My LS P7010 (65PTO HP?) can stall a bit in tall grass with my 7 foot mower when I am in M 4 range but slowing it down to M1 or 2 usually cures the loading up problem. The previous owner of my B26 (26 Engine HP) pulled a 5 foot cutter with it in heavy mowing but I don't know how fast he was going.

So it is possible to dispute the 5 HP per foot rule on either side of the high/low HP requirement. I would still go with the widest BH that your tractor can handle on the 3 PH. You can always overlap in heavy cover but have the luxury of taking a full path in light stuff so your mowing gets done faster.

I think the 5hp/ft rule of thumb is for a full cut in medium-ish cutting. You can interpolate that number however you want but it gives you a starting point. I don't know about you guys, but I'm not going to mow in 1st gear low range. I'd feel like I was sitting still but if I used that logic I could pull a 25ft cutter. :thumbsup: Its not really practical for all of my mowing and I can't stand mowing that slowly. I really don't want to try and mow at 10mph either, way to fast to try and stay in the seat and I think I'd overrun the cutter even though I've never figured out what that speed is for my mower. Right around 4mph is where I want to be mowing at and that gives me a gear or two to downshift. I also prefer a full 3pt mounted cutter so that limits the tractor more so than the cutting width does. At around 2klbs, that is alot of weight to be hanging off the 3pt with alot of distance. Either way, 5hp/ft is a guideline to start from and not a law written in stone.

 

[LD1]

I don't know about you guys, but I'm not going to mow in 1st gear low range. I'd feel like I was sitting still but if I used that logic I could pull a 25ft cutter. :thumbsup: Its not really practical for all of my mowing and I can't stand mowing that slowly.

25' cutter @ 1MPH vs 5' cutter at 5MPH.....are you really mowing that slowly?

Just my opinions....thats all Im sharing. But I have a heavy 6' mower with my 29 PTO HP. And spend most of my time in 5th and 6th gears. (bout 4.5-6MPH) Rarely do I do "average" cutting. I'm either in the densest thickest nastiest stuff you can imagine (which takes 3rd gear @ 2.5MPH) or Im in stuff that gets done 2-3 times a year, and isnt very dense. (wish I could go faster).

I need a bigger cutter. Would much rather be running an 8' cutter in 3-4th gears for the easy stuff with the option to go faster in really light material without overrunning the cutter. And then it would be 1st and 2nd gear for the nasty stuff.

Hitting a groundhog hole or something @ 5-6MPH with small 16" front rims make it hard to stay on the seat some times. Not to mention hard on the tractor.