GMC 2006 Sierra - Manual (Page 369)

For example, adding a 700 lb (318 kg) snow plow
actually adds more than 700 lbs (318 kg) to the front
axle. Using the formula, if the snow plow is 4 ft (122 cm)
in front of the front axle and the wheel base is
10 ft (305 cm), then:
W = 700 lb (318 kg)
A = 4 ft (122 cm)
W.B. = 10 ft (305 cm)
(W x (A + W.B.))/W.B. = (700 x (4 + 10))/10 = 980 lbs
(445 kg)
So, if your truck’s front axle reserve capacity is more
than 980 lbs (445 kg), you could add the snow plow
without exceeding the front GAWR.
Q:
What if I want to add heavier equipment to my
vehicle?
A:
You can add heavier equipment on the front of the
vehicle if you compensate for it by carrying fewer
passengers, less cargo, or by positioning cargo
towards the rear. This has the effect of reducing
the load on the front. However, the front GAWR,
rear GAWR and the gross vehicle weight
rating (GVWR) must never be exceeded.
{ CAUTION:
On some vehicles equipped with certain front
mounted equipment, such as a snow plow, it
may be possible to load the front axle to the
front GAWR but not have enough weight on the
rear axle to have proper braking performance.
If your brakes can not work properly, you could
have a crash. To help your brakes work properly
when a snow plow is installed, always follow
the snow plow manufacturer or installer’s
recommendation for rear ballast to ensure a
proper front and rear weight distribution ratio,
even though the actual front weight may be
less than the front GAWR, and the total vehicle
weight is less than the GVWR. Maintaining a
proper front and rear weight distribution ratio
is necessary to provide proper braking
performance.
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