GMC Sierra Instruction Manual page 351

350 Driving and Operating
United States
Canada
The front axle reserve capacity for
the vehicle can be found in the
lower right corner of the
Certification/Tire label, as shown.
In order to calculate the amount of
weight any front accessory, such as
a snow plow, is adding to the front
axle, use the following formula:
(W x (A + W.B.)) /W.B.= Weight the
accessory is adding to the
front axle.
Where:
W = Weight of added accessory
A = Distance that the accessory
is in front of the front axle
W.B. = Vehicle Wheelbase
I n f o r ma t i o n P r o v i d e d b y :
For example, adding a 318 kg
(700 lb) snow plow actually adds
more than 318 kg (700 lb) to the
front axle. Using the formula, if the
snow plow is 122 cm (4 ft) in front of
the front axle and the wheel base is
305 cm (10 ft), then:
W = 318 kg (700 lb)
A = 122 cm (4 ft)
W.B. = 305 cm (10 ft)
(W x (A + W.B.)/W.B. =
(318 x (122 + 305))/305 = 445 kg
(980 lb)
So, if the front axle reserve capacity
is more than 445 kg (980 lb), the
snow plow could be added without
exceeding the front GAWR.
Heavier equipment can be added on
the front of the vehicle if it is
compensated for by carrying fewer
passengers or less cargo, or by
positioning cargo toward the rear.
This has the effect of reducing the
load on the front. However, the front
GAWR, rear GAWR, and Gross
Vehicle Weight Rating (GVWR) must
never be exceeded.