Ford 2013 F-650 Owner's Manual page 256

Checking Tire Pressure
Always check inflation pressure when tires are cold. Never bleed air from
hot tires to relieve normal pressure build-up. Normal increase in pressure
due to service conditions is 10–15 psi (69–103 kPa), which is allowable
in truck tires.
Tires should be properly inflated to manufacturers' recommended
pressure for the size and service load in which the vehicle is being used.
See the specific tire manufacturer with which your vehicle is equipped
with for the latest information concerning service load and inflation
pressure.
It is particularly important to keep moisture from the inside of tires, and
proper selection of air compressor equipment, proper air line routing,
and the use of shop air dryers is strongly recommended to avoid
moisture in the high pressure air used for tire inflation.
Under-inflation
Tires should not be permitted to become under-inflated. Increased
flexing due to under-inflation causes heat build-up within the tire
components. This leads to reduced strength, breakdown of the rubber
compounds, and possible separation of the tire components (i.e., ply and
tread separation and reduced retreadability).
Under-inflation is the primary cause of premature tire concerns including
sudden loss of air. In addition, low inflation causes an increase in rolling
resistance. This results in reduced fuel mileage, a loss in tread mileage,
and uneven wear due to increased tread movement. To determine proper
inflation, see the tire manufacturer load and inflation guide which can be
found on the tire manufacturer website or at your local truck tire dealer.
Tire Inspection
Check the tires for abnormal wear patterns and proper inflation
pressures. Cut or broken tire casings must be repaired or replaced.
Tires should also be inspected for the following conditions. If any are
present, the tire should be removed and repaired, retreaded or scrapped
as the condition indicates.
• Any blister, bump or raised portion anywhere on the surface of the
tire tread or sidewall (other than a bump made by a repair). These
indicate the start of internal separation.
• Any cut that reaches to the belt or ply cords, or any cut that is large
enough to grow in size and depth.
• Any nail or puncturing object.
• If any stone or object is held by a tread groove and is starting to drill
into the tread base, remove the object.
2013 F-650/750 (f67)
Owners Guide gf, 2nd Printing, March 2013
USA (fus)
Wheels and Tires 255