Green Tractor Talk banner

1 - 20 of 42 Posts

·
Registered
Joined
·
138 Posts
Discussion Starter #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?
 

·
Premium Member
Joined
·
12,765 Posts
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.
 

·
Registered
Joined
·
138 Posts
Discussion Starter #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.
 

·
Premium Member
Joined
·
10,067 Posts
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:
 

·
Old Pa-pa
Joined
·
11,843 Posts
My little 1982 IH 274 is rated 30 HP Nissan engine, but 27.4 HP PTO.
All gear driven.

Guess that's why it's named a 274.
 

·
Registered
Joined
·
536 Posts
Drawbar HP.
Haven't heard that in a loong time, never did completely understand it. :dunno:
It relates to the actual pulling power of the tractor. Takes in many factors including engine HP, weight of the tractor, and gear ratios.
 

·
Senior GTT Super Slacker
Joined
·
37,841 Posts
It relates to the actual pulling power of the tractor. Takes in many factors including engine HP, weight of the tractor, and gear ratios.
Well there ya have it. Exactly why I never understood it. :lol:
:thumbup1gif:
 

·
Registered
Joined
·
12,090 Posts

·
Old Pa-pa
Joined
·
11,843 Posts

·
Registered
Joined
·
138 Posts
Discussion Starter #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.
 

·
Registered
Joined
·
1,317 Posts
Get the heavy duty, your 1023 will handle it no problem.
 

·
Premium Member
Joined
·
1,492 Posts
Get the heavy duty, your 1023 will handle it no problem.
This.

I'd bet anything these things are underrated to avoid emissions regs as much as possible.
 

·
Registered
Joined
·
356 Posts
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
 

·
Registered
Joined
·
12,090 Posts
The correct way to determine how much PTO horsepower your tractor has is to hook it to a dynamometer. Most ag dealers have them.
 
  • Like
Reactions: rtgt and Gizmo2
1 - 20 of 42 Posts
Top