875 / 2440
12-14 Edition 47
On-Highway Trucks
GVWR AND GCWR
GVWR
= Gross Vehicle Weight Rating. This rating
is used for a Straight Truck.
GCWR
= Gross Combination Weight Rating. This
rating is used for Tractors with 5th wheels.
Procedure to Determine GVWR or GCWR
1) Determine the maximum expected load on each
axle (see Weight Distribution section).
2) Select Axles, Suspensions, Brakes, Wheels and
Tires that are sized to take the load predicted by
the Weight Distribution Study. All components
must be rated equal to or greater than the expected
axle loading. See Appendix D, E, F, H, I, J, K, and
L for component ratings.
3) The lowest rated component for each axle (includ-
ing the axle), is the Maximum
Axle Rating
for
that axle.
GVWR
= Front + Rear + Lift (Axle Rating for each
axle)
GCWR
= Front + Rear + Lift + Trailer (Axle Rating
for each axle)
Example: Front Axle Rating
Expected Front Axle Load
12,420 lb
Axle rated for
13,200 lb
Suspension rated for
14,000 lb
Wheels rated for
14,000 lb
Tires rated for
13,800 lb
Brakes rated for
14,000 lb
In this example the front axle is the lowest rated com-
ponent that will carry the load predicted by the Weight
Distribution Study. Thus, the Front
Axle Rating
is
13,200 lb in this example.
Bridge Laws
Careful attention must be given to laws governing
overall weight, maximum axle loading, and axle spacing.
These laws are commonly referred to as Bridge Laws,
and are different in every State, Region, or Province.
This handbook does not cover these laws. The reader
is advised to refer to their local Bridge Law formulas.
GVWR and GCWR