Tire pressures should be checked at regular and frequent intervals and the pressures maintained to specifications.
Use an accurate tire pressure gauge and check when tires are cool.
Over inflated or under inflated tires will reduce the service life of the tire.
Never "bleed" air from hot tires. The pressure will be reduced by an increase in temperature will result as soon as
3-17.3 Loads. Loading tires beyond their rated capacity decreases tire life, requiring
more frequent replacement of tires.
Dual tires should be matched using tires of equivalent size. Tires which differ more than 6.35 mm( 1/4") in
diameter or 19.05 mm (3/4") in circumference should not be mounted on the same dual wheel. The larger or less
worn tire should be mounted on the outside.
When mounting tires on tandem drive axles follow the same instructions as specified for dual tires. However,
never install the four largest tires on one driving axle and the four smallest on the other. This method of tire
mounting will cause high axle lubricant temperatures which may lead to premature axle failures.
Replacement tires must have same rolling radius as original equipment tires in order to avoid damage to the drive
3-17.5 Mixing. It is recommended that for best overall performance that only bias or only radial tires be used on a vehicle.
However, different heavy truck tires may be used under the following conditions:
Bias or radial tires may be used on either axle of two-axle vehicles if the vehicle has dual rear wheels, or is
equipped with wide base single tires.
Either bias or radial tires may be used on the steering axle of vehicles with three more axles.
Never mix different tire sizes or constructions on the same axle.
Never mix bias and radial tires in a tandem drive axle combination.
Rotation is advisable:
If front (steering) axle tires become irregularly worn, move to rear position.
In a dual assembly, if one tire wears much faster than its mate, reverse position of tires.