What is the difference between engine horsepower and PTO horsepower?
Several terms are used by equipment manufacturers to describe the capacity of their tractors. The basic
definitions are:
Horsepower (HP): A measure of the rate with which work is done. By definition one horsepower is the amount of energy required to move 33,000 pounds a distance of one foot in a time span of one minute or likewise,
to move 1 pound 33,000 feet in one minute. It is the measure of a machine's ability to move a load.
Power-Take-Off-Horsepower (PTO): The power as determined at the power-take-off shaft.
Of the various kinds of horsepower, maximum PTO horsepower is the one most commonly used in designating the size of a tractor. On tractors that do not have a PTO shaft, brake horsepower, or maximum
drawbar hp ratings may be used.
How much horsepower do I need?
There is no set amount of horsepower for every person. Ideally you need to match the tractor to the job you want to do. If you want to operate a five-foot cutter (shredder), a good rule of thumb is 20 PTO horsepower (not engine horsepower). A six-foot cutter requires roughly 30 PTO horsepower. Click here to see our tractor comparison based on implement need. It can help you get a handle on what you might need. Remember, we're here to help, so please call us to talk to one of our experienced salesmen personally to help determine your needs.
Is two-wheel drive or four-wheel drive better?
Tractors can be divided into 3 categories: 2-wheel drive, front-wheel assist or unequal 4-wheel drive, and
equal 4-wheel drive tractors. Each one of these tractors has different tire configurations and different ballast
requirements.
Two-Wheel Drive Tractors (2WD) are most commonly used in dry or upland farming situations and for transportation. They range in size from 5 HP - 200 HP and need 80% of the weight distributed over the rear axle
to maximize traction. The biggest advantages of this type of tractor over other 4-wheel tractors are smaller turning
circle, simplicity of design, fewer mechanical parts and lower purchase price. However, a 2WD tractor does not
work at all well in wet, hilly and muddy conditions.
Front Wheel Assist (FWA) is commonly known as 4WD or unequal 4-wheel drive. It is the most popular 4-
wheel tractor in many parts of the United States and worldwide. These tractors range in size from 5 HP - 240 HP
and are capable of delivering between 50-55% of the rated power at the drawbar. Typically, between 75% and
85% of the rated engine HP is delivered to a rear PTO (Power Take-Off) on any diesel tractor. On a FWA tractor the front drive tires are smaller than the rear tires. These tractors require 40% of the
weight distributed over the front axle and 60% over the rear axle. The major advantage in using this type of tractor
is that it can deliver 10% more power to the ground at all 4 tires for the same fuel consumption, and thus has
much better traction and flotation capabilities than 2-wheel tractors of the same size. FWA tractors normally cost
about 15-35% more than the same horsepower two wheel drive tractor.
Equal Four-Wheel Drive (4WD) tractors have all four tires of equal size and range in size from 35 HP - 600 HP. This tractor type has the greatest power to weight ratio and can deliver between 55-60% of power at the
drawbar. It is challenging to maneuver and often the size and expense makes these tractors impractical.
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