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Old 06-13-2023, 05:24 AM   #5
Bill
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Join Date: Feb 2003
Location: The mountains of Scottsdale, AZ, and the beaches of Maine
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Quote:
Originally Posted by Wavery View Post
HP shouldn't be the deciding factor. Stopping power is the most important aspect of any tow vehicle and the hardest to determine.
Wavery -

You are right, of course. Horsepower is not the only thing to consider. These days, there is a formal definition of tow rating, and an exhaustive proof test, known as SAE spec J2807. All manufacturers use it, and all the definitions and vehicle configurations used in the proof tests are tightly controlled. A manufacturer cannot claim or advertise a tow rating number until his vehicle has passed the J2807 test at the proposed rating.

J2807 concentrates on a grueling 11-mile uphill run on a road called the Davis Dam road in Arizona, which of course involves horsepower, as well as torque, engine and transmission cooling, speed, acceleration, and all the other things we tend to think of as the muscle part of towing. But less known is that J2807 also has a braking section. In other words, a manufacturer cannot claim a tow rating of, say, 5000 pounds until his vehicle has passed both the Davis Dam road test and the braking part off the test, with a 5000 pound trailer.

At 27 pages, J2807 is fascinating reading, readily available from any number of sources. Just Google it, and enjoy.

Bill
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