HP Rating: Gross or PTO???

Neophyte · Aug 12, 2003

When looking at attachments, they often have recommended HP ratings. However, they don't specify if gross or PTO HP. Are these Gross HP ratings for the tractor overall or PTO HP ratings?

Gatorboy · Aug 12, 2003

I'm not sure, but I always use my PTO HP as the number I want to compare attachment HP numbers to when deciding if I am within the limits.

HayDR · Aug 12, 2003

If an implement requires the power if a PTO, IE a tiller, then the PTO HP is what is needed to safely operate that implement.

cowboydoc · Aug 12, 2003

CCI is right. Gross hp really doesn't mean alot. It's how much power you put to the pto that matters. Doesn't do you any good to have say a 60 hp tractor and only have 40 hp at the pto if you need 50 hp at the pto. Depending on the engine and tractor make the gross hp is anywhere from 20-40% greater than the pto hp.

Neophyte · Aug 12, 2003

OK, that makes sense.

Non-PTO implements (box blade, rake, etc.): Use Gross HP
PTO Implements (rotary cutter, tiller, etc.): Use PTO HP

Is this correct?

slowrev · Aug 12, 2003

I would use Net HP for Non PTO implements instead of gross. Gross HP is the HP the engine produces without any water pumps, Alternator,etc. Net HP is the HP that the engine really puts out to the tranny.

Neophyte · Aug 12, 2003

For 20-40HP tractors, is it safe to assume that Net HP is usually only 1-2HP less than Gross HP?

Golfgar4 · Aug 12, 2003

( For 20-40HP tractors, is it safe to assume that Net HP is usually only 1-2HP less than Gross HP? )

I wouldn't assume that.

It seems to me that, generally speaking, you can expect about that much of a difference for a gear tranny tractor. Then knock off a couple more hp for a shuttle shift transmission, and even a few more for a hydrostatic transmission. I think I've seen as much as a 10 hp difference in gross vs. pto for a hydrostatic transmission.

I'm sure others will have even more accurate inforrmation. But it's easy enough to check out the specs when you're shopping around. /forums/images/graemlins/wink.gif

Gary_in_Indiana · Aug 12, 2003

For 20-40HP tractors, is it safe to assume that Net HP is usually only 1-2HP less than Gross HP? 

Garry gave you some great insight above. The example to which I'll refer is my own JD 4200. I believe the gross HP rating is something in the 26-28HP range. My PTO is rated at 20HP. That translates into a gross HP rating 30-40% higher than the PTO HP rating. Quite a difference, to say the least. /forums/images/graemlins/smile.gif

fivestring · Aug 12, 2003

As Garry and Gary (and now this Gary) have said, the PTO hp drop from a gear tranny is a bit less than with hydro. PS also takes up hp. My tractor (gear) is 20-21 hp at the engine and 17 at the PTO. Not as much drop. If you use the PTO listing for your tractor, you should be ok when buying implements that need XX hp. Now, do the Garys have you confused?