Tractor horsepower curiosity

Hey guys

I've noticed that the newer tractors seem to be advertised with engine horsepower; older ones were commonly rated by drawbar or pto horsepower. Is there a "rule of thumb" for comparing these ratings? When did this rating change?

Thanks

Lew

I think that the tractor companies should be sued for doing this. The horse power that they are quoting is a worthless number. It is gross engine horse power at the flywheel.
Example John Deere 8430 250 pto hp
replacement John Deere 8295 245 pto hp. but advertised as 295 hp.
As for a rule of thumb: take about 80% of engine horse power and that will be close to pto.

Thanks JD

I doubt I'll ever buy anything new enough to hafta worry about it but it just seems like the hp ratings they advertise in these new "compact tractors" (I see the TV ads like probably everyone else does) looks awfully high.

Lew

John Deere started advertising tractors at engine HP instead of pto HP because other manufacturer's from other than the USA were doing it. One that comes to mind is Kubota. I think JD went to engine HP after the 55 series models as my 4255 is rated at 120pto hp.

It's all about hype. Using engine hp numbers allows manufacturers to use a bigger number. The first place I remember noticing the change was with compact tractors. In many cases, the difference there might only be 3 or 4 hp with those small tractors. (compared to pto hp)

Some of us are old enough to remember when the standard was how big of a plow a tractor could handle. Or before that even, how big of a thrasher it would spin.

Interesting point. My 22 HP Kubota is 17 pTO HP. My 4830 Ford is 70 HP, but when I bought it, it was advertised as 62, which is the PTO HP. My 8N (with the 9N engine) is questionable, but they all perform admirably at their assigned tasks.

I think you have to try them to see if it does what you need and ignore sales pitches.

You just have to read more closely with tractors sold to consumers and not farmers.

One example is a new Deere 4005 compact-utility tractor. Deere's main ad shows it as having a 41.5 horsewpower engine and does NOT say it's a 41.5 horsepower tractor. When you look at the Deere specs, it shows:

Gross engine horsepower - 41.5
SAE PTO horsepower - 35
Engine size - 133.6 cubic inches

Real farm tractors are still rated by PTO and drawbar horsepower. Figures for compact utility and garden tractors have alway been "consumer" rated - and often done so in a fictitious way.

Nebraska Testing put an end to wild claims by farm tractor makers.

SAE net horsepower also put an end to many wild claims in cars and small trucks around 1973.

But with the class-action settlement with lawn and garden stuff- I think things now will be even more confusing, not less.

With compact utility tractors it seems - it's still "anything goes" with advertising and which figures they want to stick up front. When

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It changed a while ago. Just get a spec sheet and look at the pto
hp. Also note if its DIN or ISO rated. One has the engine belted up
to everything, the other is a bare engine.

when I worked at Case the MX series came out, they told us pto hp was 15% less than engine hp due to power loss for the trans. and hydraulics, we found they were putting out more than they were rated, for example the MX 240 was supposed to be 200hp pto but found they were putting out a full 240 at the shaft, not suprising, it's a Case!!

John Deere started a new numbering system for their farm tractors (utility) that displays the bare-engine HP on the side of the hood (sort of). i.e., "6115D" identifies a six series tractor that has 115 bare-engine HP. (it really has 117 HP but they round to the nearest 5) They say it has 95 PTO HP but in the Nebraska Test it pumped out 99+. Max drawbar HP at Nebraska came in at 81.05. I hope this cleared things up. (;>))

Europe has uses gross rather than net power ratings. North America is just catching up.
Auto industry has rated vehicle engines at flywheel HP instead of rear wheel HP for decades

I beleive all the 4wd tractors are and were rated as engine power and the row crop tractors were rated as pto power.

They've been rating combines at flywheel hp for years.