# What is drawbar horsepower?



## IslandBreeze (Nov 6, 2012)

I know what engine hp & pto hp is & what it relates to but don't know what drawbar hp is. When I think draw bar I think of the bar that runs across the back of a tractor that is hooked up to hydraulics & is used to pull a trailer, rake, baler etc. Maybe I've been calling that the wrong thing all my life. Any info would be greatly appreciated, especially if I'm wrong. Haha

Thansk, Randy


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## deadmoose (Oct 30, 2011)

Reserving the right to be wrong it is pulling power.


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## mlappin (Jun 25, 2009)

What deadmoose said.

Where is a somewhat comprehensive article on the various measurements of horsepower.

http://en.wikipedia.org/wiki/Horsepower


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## IslandBreeze (Nov 6, 2012)

I will definately check that out mlappin because that doesn't make a whole lot of sense to me. I never heard of it before today


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## slowzuki (Mar 8, 2011)

Yup drawbar power = pulling power, note that drawbar pull is what some people really mean when they say drawbar power. A horse has a high amount of drawbar pull, but only 1 hp, an old antique heavy but low hp tractor has high drawbar pull. This is a lot of what people get confused with when comparing lawn tractors etc.

The measure of horse power was set in england using a rope and pulley system with lots of different horses to raise a weight. On average a workhorse could raise 550 lbs at a rate of 1 ft per second.


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## IslandBreeze (Nov 6, 2012)

Well slowzuki, I've already learned something today & it's only 7am. It's going to be a good day.


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## NDVA HAYMAN (Nov 24, 2009)

It is the amount of power available to pull a drawn piece of equipment such as a plow, disc, etc. When manufacturers state that it takes 30 horsepower per shank or etc. to pull something, they are talking about drawbar hp and not pto or engine horsepower. Hope that clears it up for ya. Mike


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## slowzuki (Mar 8, 2011)

I should add, just because you have enough drawbar hp to match the specs, doesn't mean you can pull it, if you can't generate enough drawbar pull to get to the speed that your drawbar hp was achieved at... then you're sunk. You can generally ballast a tractor heavier to raise the drawbar pull if it isn't being limited by available engine torque. Used to see some of the old tractors heavy enough they run out of engine before they run out of traction, they won't get anymore drawbar pull with more weight.


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## mlappin (Jun 25, 2009)

Torque does the work, HP is how fast you can do the work. Lets say if you could drop a 40hp kubota engine in a BIG four wheel drive, if you could get it reduced enough you could pull the same load as a 400hp engine, the small engine would end up with the same torque with enough gear reduction, but it lacks the horsepower to do the work in a timely manner.

Or take an auger handling corn. A 1hp motor would normally handle the load unless you increase the load by running a grain that doesn't handle as well or increasing the length of the auger. You could do one of two things, you could change pulley sizes by either running a smaller pulley on the motor or a larger on the auger, either way you decrease the speed of the auger and the required HP to run it, BUT you also get less work done. Had this exact same thing this fall, old batch dryer would dump corn at 16.7% moisture and 120 degrees. New continuos flow dumps 18% moisture corn at 140 degrees, hotter wetter corn is much "stickier" and handles harder. The 1hp motor we've had on the auger for years feeding teh grain cleaner couldn't handle it and was blowing overloads constantly, changed to a 2hp and end of problem. I could have reduced the speed of the auger thru changing pulley sizes and thereby giving the motor a mechanical advantage because of the reduced speed of the auger, but then it would not have handled dryer corn fast enough so more HP was needed to run at the same speed.

Clear as mud?


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## JD3430 (Jan 1, 2012)

Then there's torque rise, off pedal torque. low rpm torque.....
I like a diesel that makes torque down low. I've got a little DT466 in my dump truck. Only 250HP, but it'sd a "HT" model (high torque). It makes like 90% of its' torque right off idle to get the load moving or a nice "hole shot".
I like to look at an engine's ability to make torque down low because it also generally uses less fuel. less revs=less fuel.
Never cared much for the Ford v-8 powerstroke diesels compared to the 5.9L Cummins. They just can't match an in-line 6 torque down low.
In my never-ending tractor search saga, I found a great tractor-the Ford/NH 8340. It's only 130HP, but 7.5L of displacement. Gotta love a big 6cyl turned down to about 1/2 of its' power potential. Would last a long time and live an easy life in a 10,000lb medium sized tractor.


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## slowzuki (Mar 8, 2011)

That doesn't sound right, I've been around two different 7740's, the 4 cyl version, which is about 85 or so pto hp, I thought the 8340 had about 20 more hp?



JD3430 said:


> In my never-ending tractor search saga, I found a great tractor-the Ford/NH 8340. It's only 130HP, but 7.5L of displacement. Gotta love a big 6cyl turned down to about 1/2 of its' power potential. Would last a long time and live an easy life in a 10,000lb medium sized tractor.


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## Mike120 (May 4, 2009)

slowzuki said:


> That doesn't sound right, I've been around two different 7740's, the 4 cyl version, which is about 85 or so pto hp, I thought the 8340 had about 20 more hp?


You're right, the 7740 was the European version of the 7710 when they quit making it in NA. It had the 5.0L-4 cyl instead of the 4.4L in the 7710. They both tested a little over 86 hp at the PTO. The 8340 is European also and tests at 110 hp at the PTO. That big 7.5L 6 cyl can be cranked way up, it makes 210 hp at the PTO in the 8970.....just takes a lot bigger fuel line.


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## JD3430 (Jan 1, 2012)

Big jump to the 8340. Not a very good looking tractor, but powerful and CHEAP.


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## Mike120 (May 4, 2009)

JD3430 said:


> Big jump to the 8340. Not a very good looking tractor, but powerful and CHEAP.


Beauty is in the eye of the beholder...It's a jump, but those extra two cylinders make all the difference in the world when you need the power. Cranking the PTO on the 8340 only uses a tad over 1 gal/hr more than my 7710 but the hp and response is much better. Being European, it also comes with the reinforced, heavy duty "sun roof".


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## JD3430 (Jan 1, 2012)

I don't think it's a UGLY tractor, but the blue Ford color never appealed much to me. Neither does Kubota orange, but I own one!!
I really like the idea of that 7.5L NH diesel, though. Lots of displacement means long life, lugging power and extra weight to keep the tractor stable.


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## JD3430 (Jan 1, 2012)

slowzuki said:


> That doesn't sound right, I've been around two different 7740's, the 4 cyl version, which is about 85 or so pto hp, I thought the 8340 had about 20 more hp?


You're right, it's about 20-25 more at PTO, I was talking engine HP. The bigger point is that I'd rather have a bigger engine turned way down than a smaller engine turned up.


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