What range of HP does 1-3/8" 6-spline PTO cover?

[strantor]

I wouldn't be surprised to learn that it's all over the map, but generally speaking, if someone says they have a 1-3/8" 6-spline PTO without saying anything else about their tractor, what size/HP bracket do you assume their tractor is in?

 

[Hay Dude]

Could be just about any size. I have a 200HP tractor and run a 1-3/8 6 -spline on some stuff. Other I have the 1000 small and large.
Its all over the map. My rear mowers are 540. My front mower is 1000, but runs off a 540 stub.
Generally speaking, really large, high HP implements, like large square balers are 1-3/8” 1000 or 1-3/4” 1000.

 

[Rustyiron]

I didn't realize until recently that higher rpms will endure higher loads without a proportional increase in the size of the mechanism itself.
Now I'm no "EINSTEIN" but noticed that looking at 90* gearboxes and their HP ratings such as on a bushog then further questions to those that I believe would know.
I'd be very curious to hear from others with an actual schooling on this for a correction or explanation
It makes sense that you only see the 21 spline 1000rpm on higher HP tractors, at least here in the US.

 

[strantor]

I didn't realize until recently that higher rpms will endure higher loads without a proportional increase in the size of the mechanism itself.
Now I'm no "EINSTEIN" but noticed that looking at 90* gearboxes and their HP ratings such as on a bushog then further questions to those that I believe would know.
I'd be very curious to hear from others with an actual schooling on this for a correction or explanation
It makes sense that you only see the 21 spline 1000rpm on higher HP tractors, at least here in the US.

Horsepower = Torque x RPM / 5,252
So if you want to double the HP you can either double the torque, or the rpm (or adjust both proportionally).
200HP = (540RPM × 1,946ft×lbs)/5252
200HP = (1,000RPM × 1,051ft×lbs)/5252

 

[Texasmark]

Another way of judging the size of the gearbox by the RPM rating is that a 1:1 ratio means that the number of teeth in both gears, thus the diameter of both shafts gears are identical. On a 10:1 ratio for an example, since the teeth have to mesh, they have to be the same size but you need 10X the number of teeth on the output shafts....that means that the "circumference" of the mounting surface for the 10:1 is much larger requiring a much larger casting even though the HP (as mentioned above) rating remains constant. Don't confuse housing size with HP rating. You want any implement HP rating to exceed the max PTO HP applied........and when you don't do that and wind up accidentally high centered on a berm....poof goes a gear box!!!!!!

 

[Tx Jim]

It makes sense that you only see the 21 spline 1000rpm on higher HP tractors, at least here in the US.

Some older JD tractors such as model 1010 with HP as low as 35 had dual speed(540/1000) rpm pto speeds.

 

[Rustyiron]

Horsepower = Torque x RPM / 5,252
So if you want to double the HP you can either double the torque, or the rpm (or adjust both proportionally).
200HP = (540RPM × 1,946ft×lbs)/5252
200HP = (1,000RPM × 1,051ft×lbs)/5252

I knew someone here didn't miss that class in school

 

[Farmer495]

I would assume they have anything from a compact and up.

I'd just assume anything under 200 PTO HP.

 

[mcfarmall]

Answer to the OP's question: 0 to approximately 200 hp.