[AT] Horsepower question

[Cecil Bearden]

The horsepower data on tractors has changed in the last few years.  I found 
out this by accident and it cost me a few thousand dollars.  I bought a Case 
JX85  85hp tractor.  It would not pull a 9 ft disc mower in JUly with the 
air conditioner on without getting hot.  I traded it for a TS110 New Holland 
that is rated at 110 HP.  However, both of these tractors are rated at 
engine hp, not PTO as they were rated for 50 years or more...  There is a 
lot of loss in the drive train.....  I would not own another Case/IH again..

Cecil in OKla

----- Original Message ----- 
From: "Larry Goss" <rlgoss at insightbb.com>
To: "Antique tractor email discussion group" <at at lists.antique-tractor.com>
Sent: Wednesday, October 06, 2010 10:45 PM
Subject: [AT] Horsepower question


It's hard to "draw rules of thumb" out of the Nebraska tests. But here 
goes --- Drawbar pull is generally in the range of 50% to 60% of the weight 
of the tractor. Some Caterpillars drop as low as 45%. Drawbar horsepower is 
in the range of 50% to 70% of Belt or PTO horsepower. Slippage of the drive 
wheels varies from 2% to 15% regardless of steel or rubber, but rubber 
generally runs a bit higher than steel I don't know that the tests were ever 
run with the intent of maximizing the balance, traction, weight, etc, the 
way we do as pullers. I'm sure the slippage values would be much higher if 
they did.

I found out a few months ago that a one of my wife's close personal and 
professional friends is the daughter of one of the men who ran the Nebraska 
tests for years. I hoped she would be able to tell me stories from Lincoln 
about those tests. Unfortunately, she studied music and had no interest in 
what her father was doing at the University.

Larry




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