Chevrolet 1979 Light Duty Truck Owner's Manual page 94

I nflation Pressure
The cold inflation pressures for your factory installed tires are listed
on the Certification Label. Your tires must be inflated to these
pressures to obtain the GVWR (Gross Vehicle Weight Rating) or
G A WR (Gross Axle Weight Rating). Incorrect tire inflation pressures
can have adverse effects on tire life and vehicle performance. Too low
an air pressure causes increased tire flexing and heat build-up. This
weakens the tire and increases the chance of damage or failure and can
result in tire overloading, abnormal tire wear, adverse vehicle handling,
and reduced fuel mileage. Too high an air pressure can result in
abnormal wear, harsh ride, and also increase the chance of damage
from road hazards.
Lower inflation pressures can be used for light truck-type tires with
reduced vehicle loads. After finding the load on each tire by weighing
the vehicle on a scale, the minimum cold inflation pressures can be
found in the Tire/Wheel Load
of this Section.
Tire inflation pressures should be checked at least monthly (including
the spare if so equipped). Always check tire inflation pressures when
tires are "cold".
1 .
The "cold" tire inflation pressure applies to the tire pressure when
a vehicle has not been driven more than one mile
after sitting for three hours or more.
2.
It is normal for tire pressures to increase
(30
inch to 60 kilopascals) or more, when the tires become hot
from driving.
after driving your vehicle. Bleeding serves to reduce "cold"
inflation pressure and increase tire flexing which can result in tire
damage and failure.
3. Passenger-Car-Type• tires:
For sustained driving at speeds of 75 mph to 85 mph (1 20
km/h to 1 40 km/h), in countries where such speeds are
permitted by law,
(30
kPa) above the stated cold inflation pressures on the Certification
Label up to the maximum for each load range stated in the chart below.
Sustained speeds of 75 mph to 85 mph (1 20'km/h to 1 40
km/h) are not advised
require pressures greater than the maximum pressures stated for each
load range in the chart on the next page .
speeds over 85 mph (140 km/h), where such speeds are
permitted by law, is not advised
with special high speed tires available from
Truck-Type• Tires:
For sustained driving at speeds over 65 mph ( 1 00 km/h),
where such speeds are permitted by law,
pressures should be increased
Tire/Wheel Lqad and Inflation Pressure Charts for the load being
carried. Do not exceed the wheel capacity limit shown in the Wheel
Code and Limits Chart.
&
Inflation Pressure Chart at the end
Do not
"bleed" or reduce tire inflation pressures
cold inflation pressures must be increased
when the
10
psi
5-14
4 to 8 pounds per square
4 (30
psi kPa) adjustment would
Sustained driving at
unless your vehicle
many t
(70
kPa) above those stated in the
( 1 .6
kilometres)
4
psi
is equipped
i e ealer
r d s
.
cold inflation