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PTO HP vs motor HP confusion on 1023 in practice....

13K views 41 replies 16 participants last post by  tommott77 
#1 · (Edited)
PTO HP vs motor HP confusion on 1023 in practice with hydrostatic....

Hi all,

I was looking around for a small flail mower that would work with my little 1023. In my search I found a 41" flail that required an ambiguously stated 18HP. I contacted the seller to see if the 18hp was for engine or PTO HP. The response I got from the seller was as follows....

" If it is a geared tractor then the 18 hp is PTO if it is hydrostatic then it is engine. The reason is the hydro can set engine speed / pto separate of the forward speed."

I have yet to buy any PTO driven implements 1023, and this distinction is news to me. I believe that my 1023 has around 14-15 pto hp. Any thoughts as to if what the seller is saying holds water, and/or if I'd be ok as the seller states in actual practice?
 
#3 ·
In experience if the PTO driven implement is rated by HP it is a requirement of tractor PTO HP.
What ^^^^^ he said.

" If it is a geared tractor then the 18 hp is PTO if it is hydrostatic then it is engine. The reason is the hydro can set engine speed / pto separate of the forward speed."


The comment made by the seller makes no sense. PTO HP is PTO HP, it makes no difference whether hydro or geared. And to the best of my knowledge, ALL tractors, regardless of transmission type can set their engine speed/PTO speed separate from forward speed.
 
#4 ·
That's what I had figured originally, but they had some other implements rated differently.

Anybody heard of this type of distinction of hp differences though with having a hyrdostatic vs geared tractors though? Not sure if I should take this guy for his word or look for something smaller.
 
#5 ·
Back in the day, tractors were rated by PTO HP and drawbar HP. The drawbar rating isn't used much anymore, at least not on smaller tractors. Engine HP ratings are the brainchild of someone with a marketing degree that's never set foot on a farm.

The reason engine HP numbers are pretty much worthless is due to the drivetrain. A geared tractor will have less parasitic loss through the drivetrain so a 20 HP engine might put 18 to the PTO. A hydrostatic drivetrain has a higher parasitic load so that same 20 HP engine in a hydro tractor may only put 15 HP to the PTO because running the hydro pump saps more power than a clutch and gears. I'm just making up numbers to illustrate the principle, but at the end of the day when shopping for PTO implements you need to match them to the PTO HP your tractor has. :good2:
 
#8 ·
It relates to the actual pulling power of the tractor. Takes in many factors including engine HP, weight of the tractor, and gear ratios.
 
#15 ·
So I decided to call the guy back to get some clarification on that reply he gave me. He was out today, but I spoke to another sales girl who said the exact same thing that hydrosatic being able to handle it due to engine control, ect, ect. I'm wondering if they are rating the hydrostatic at different rpms compared to geared tractor for their HP figures. The guy that emailed me supposedly has 35 years experience when it comes to this stuff and I'm supposed to call him back tomorrow.

They do have a lighter duty model for 14-15hp tractors. I'd be using it to predominantly tame some kudzu growth and other brush so I figured I'd probably want to go with the heavy duty model if possible.
 
#16 ·
Get the heavy duty, your 1023 will handle it no problem.
 
#18 ·
Hi All
I can understand where the sales man is coming from. You must drive the flail mower at design speed (540 RPM).
With hydrostatic drive you can vary ground speed independently of engine speed. So if you set the engine at pto speed you have infinite speed control between zero and max speed.
Where as with a conventional gear box you are restricted 3 of 4 usable speeds as long as you keep the PTO at 540 RPM.
With the Hydrostatic drive, as the flail mower loads up you can slow the tractor down much easier than a manual transmission which you will have to change down gears.
I think you will find a Flail mower takes a lot more HP to drive than a slasher of equal width.:dunno:
Regards John
 
#23 · (Edited)
Hi All
I can understand where the sales man is coming from. You must drive the flail mower at design speed (540 RPM).
With hydrostatic drive you can vary ground speed independently of engine speed. So if you set the engine at pto speed you have infinite speed control between zero and max speed.
Where as with a conventional gear box you are restricted 3 of 4 usable speeds as long as you keep the PTO at 540 RPM.
With the Hydrostatic drive, as the flail mower loads up you can slow the tractor down much easier than a manual transmission which you will have to change down gears.
I think you will find a Flail mower takes a lot more HP to drive than a slasher of equal width.

Regards John
Thanks so much. So in essence I can drive slower with my tractor. That makes sense. I have definitely heard that the flails take more HP than a brush hog, which is why I wanted to double check what the dealer was telling me.

Unfortunately a brush hog is not a viable option as the property needing attention is in the western NC mountains and there are too many slopes, undulations, nooks, crannies, ect for a rotary. I also need the mulching capabilities of a flail to destroy as much old kudzu growth as possible.
 
#19 ·
The correct way to determine how much PTO horsepower your tractor has is to hook it to a dynamometer. Most ag dealers have them.
 
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#27 ·
Spoke to the dealer again and again they reiterated that I should be ok with the medium duty unit. What they were saying is that in essence with the hydrostatic I could go slower and increase power to the PTO without speeding up the tractor and the workout load on the cut simultaneously as with a geared tractor. They felt that a lot of brush work would be a stretch for the lighter duty unit. So I went ahead and placed the order medium duty unit.

I only have about an acre and half that needs to be cleared and was planning on doing a slow as possible job with it anyway, probably setting aside a couple days. I plan to first pull up as much of it as possible to loosen things up with a ratchet rake on my loader and then go over it with flail mower. They said to call when I get it and they will give me some pointers on how to best set it up and use it to best match my tractor.
 
#33 ·
I believe drawbar horse power is something that is calculated for geared tractors in a given gear. As hydrostat tractors have an infinite range of speeds in there transmissions drawbar horse power doesn't mean anything. Years ago a lot of implements were rated for HP at a given speed so drawbar HP was important as one tractor may be in 4th gear where another is in 3rd to get that rated speed. That is how you could tell if your tractor was up for the job or not.
Ron
 
#38 · (Edited)
Hey all, just wanted to post an update. Got back from the mountains yesterday after going after the property and the kudzu for a couple days with the 1023 and the flail mower. Everything worked exceptionally well. Not only did I get all the growth cleared in the spot that 'had' to get done, but it also cleared 500' of the old overgrown driveway going up the mountain with as much as a 17% grade in two days of work!

Here's a before and after video. Note that the before videos were taken in January and all the dead growth was already overtaken by new green growth as seen in the last picture. The trickiest part was the back part of the build site (looking up around 3:10 of the 'after' video). It was steeper than other areas, still nowhere close to the driveway up the mountain however, but was covered in rocks, ruts, bumps, humps, soft ground you name it. The rough terrain coupled with the grade was quite tricky. You definitely had to keep track of where every wheel was and where it was going at all times. The first time going up the driveway probably my had my heart up a good bit as well, fortunately other than some fallen trees there terrain wasn't too bad.

All and all the tractor and the 'cheap' flail mower performed phenomenally well. There's was literally a couple inches of dead growth of kudzu everywhere but the mower and tractor ate it up great, to the point where the only hiccup was all the dust it was making clogging up the radiator filter and the grill several times. There were instances of it bogging down, but it was pretty easy to familiarize yourself with and staying within a comfort zone of both the tractor and the mower; going slow, downhill as much as possible and taking on the heavy brush in conjunction with the overgrowth in several passes. I don't think a couple more PTO HP would really have made a difference either way. I even ran the mower going up the driveway once!

Before.....

https://www.youtube.com/watch?v=-1qTqy8USq4

https://www.youtube.com/watch?v=klQlYk5_xOQ
 

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#42 · (Edited)
.....also should mention that I decided to mow my lawn with the flail mower when I got back. It had been two weekends since I had cut it due to getting everything lined up for the trip. This usually leads to quite a messy job with clippings everywhere eventually making their way into the house.

Not sure how these 'before' and 'after' pics will come out but, again, it performed great!Even with the installed 'hammer' blades for extreme brush the quality of the cut was not that worse than my 54" MMM and virtually left no noticeable clippings. It may have taken a bit longer with the flail, but it got into many spots I can't get with the MMM and cut a good bit of time off my much despised follow up with weed eater.

I'm seriously considering purchasing some grass or mulching blades and retire retiring the MMM.
 

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