How much (HP) is enough?

[chuck_j]

Hi,

I am just starting to look for tractor (most likely blue /w3tcompact/icons/smile.gif) to mow about 7 acres of fairly smooth (cultivated - was corn, more recently hay) terrain. As the lot http://www.erols.com/oregon/lot_pics.htm is a long rectangle with what I am guessing to be about a 6 - 7 per cent grade, how much HP would be required to pull a 72" finishing mower up the hill at a reasonable (6 - 8 mph ??) speed?

 

[_RaT_]

I would check with the manufactuer of the mower and see what minimum HP's they recommed for the mower. I have an 80" mower that needs about 30 HP minimum, but more importantly, it needs a tractor that won't come off the ground going up hill. The mower weighs 1500+ lbs, hangs about 6.5' off the rear. I have it attached to a 2WD International with about 50 HP's and tons of weight up front. The front wheels still come off the ground when going up the steepest hills. If it had a loader up front I suspect this would not be the case. Rat...

 

[ejb]

If all you want to do with the tractor is mow 7 easy acres, I would think you wouldn't need that much HP. I would guess something in the range of 20-30HP would be more than enough for that task. Possibly even less. My small tractor is a 15 year old Yanmar, 2WD 27HP tractor, and it carries a 60Inch belly mower, and pulls an extremly heavy (when full) grass catcher/vacuum attachment that holds about 125cubic feet of grass. Even with a full load of damp grass, 200+ pounds of driver and the belly mower attached, I have never felt like I needed more horsepower for mowing, even up steep hills.

Good luck. Let us know what you decide on.

 

[W5FL]

I takes very little HP to mow with a finish mower for grass that is mowed regularly. If you let it get away from you, a finish mower is the wrong mower. I believe you would be pleasantly surprised at how well a rotary mower will cut fields like you have and give a nice finish look to them.

I would not personally mow at 6-8 mph over previously cultivated ground. Probably 4 to 6 mph is more like it. Your ability to keep you in the seat and the tractor on the ground is probably the limiting factor. It will take more HP to pull the 8% grade than to mow it.

Typical manufacturers specifications to pull a rear finishing mower of 5 to 6 ft is 25 pto hp. Typical specification for a 6 ft light to medium duty shredder is 30 to 50 pto hp. But here you are not mowing rather making matchsticks out of trees up to 2 inches in diameter.

There is a nice chart on mowing time (acres/hour) at http://www.zimmererkubota.com 6 ft mower 4 mph 2.4 acres/hour including time for a cup of coffee. /w3tcompact/icons/smile.gif

 

[W5FL]

Paddock,

My front end stays on the ground, but the rig weighs over 8000# without the 1000# 6 ft mower. The loader plus over 500# of water/antifreeze in the front tires helps the situation a great deal. I can handle a 7 ft mower, but it just won't fit on my trailer and six foot was a good compromise. But with a 7 ft mower I could widen out the tires another 8 inches! /w3tcompact/icons/smile.gif

I saw a guy asking about putting a seven foot mower on a 50 HP Massey and the dealer was trying to tell him as nice as he could that the mower would be too heavy for his tractor. /w3tcompact/icons/smile.gif

 

[Anonymous Poster]

I have a TC29D and use it to mow with a 72" Land Pride FDR2572 pull behind finish mower. The tractor handles it easily in the middle range except for one place where I have a steep hill, then I have to slow down. I'd say it would be just right for what you want to do. I've never tried to mow as fast as you mentioned, but it's still spring and the grass grows fast and is very thick. I don't know exactly how fast I'm mowing, but I guess around 5 1/2 MPH. I could probably go faster in most places. I'm not worried about whether the tractor will handle it, I'm sure it will, but if I go too fast the mower won't cut the grass well when it's this thick. Later this summer I might try going faster.

 

[chuck_j]

Thanks to all who replied for their insight and comments. Am looking really hard at a TC29D, but was curious after reading the comment Danny Y had about having to back off a bit when going up a hill. Thanks for expanding on that comment Danny!

 

[Bird]

Wen, I'm just a little skeptical of Zimmerer's estimates of acres per hour (or maybe I'm just a bit slow). I usually mow in mid-range, which according to my manual provides a top speed of 5.3 mph, but yesterday I was in a hurry, so I mowed approx. 7 acres of pasture in high range as fast as my rear end could stand to ride on pretty rough ground, and it still took me 2.6 hours non-stop with a 5' brush hog. Of course, I did have to maneuver around 9 pecan trees, into the corners, etc., but I've never been able to do a mowing job as fast as Zimmerer's chart. Maybe I just haven't learned how to do it yet./w3tcompact/icons/wink.gif

Bird

 

[W5FL]

Don't be skeptical. Use your EXCEL spread sheet. 2.4 acres/hour x 2.6 hours = 6.24 acres. You mowed 7 acres. You beat the estimate. You probably forgot to stop and drink the coffee!!! /w3tcompact/icons/laugh.gif

 

[Hawgee]

EXCEL SPREAD SHEET??? /w3tcompact/icons/frown.gif

Now we are getting worried. The time spent on that much ground sounded right to me, but then I don't use Excel. Most the time it's seat of the pants and at times, that equals Excess. Sore butt and all. But you can be darn sure of the tool box doubling as a cup holder with straw for both hot and cold running. /w3tcompact/icons/crazy.gif
Our grass looks wet compared to the pictures of the lot. (Pacific NW) Here, the damp grass cuts better than the late summer dry condition if you stay ahead of it.

"What is a weed? A plant whose virtues have not yet been discovered."
Ralph Waldo Emerson (1803-1882)