space-saver or temporary use spare tires, tires with nominal rim
diameters of 10 to 12 inches or limited production tires as defined in
Title 49 Code of Federal Regulations Part 575.104(c)(2).
U.S. Department of Transportation-Tire quality grades:The U.S.
Department of Transportation requires Ford to give you the following
information about tire grades exactly as the government has written it.
Treadwear
The treadwear grade is a comparative rating based on the wear rate of
the tire when tested under controlled conditions on a specified
government test course. For example, a tire graded 150 would wear one
and one-half (1 1/2) times as well on the government course as a tire
graded 100. The relative performance of tires depends upon the actual
conditions of their use, however, and may depart significantly from the
norm due to variations in driving habits, service practices, and
differences in road characteristics and climate.
Traction AA A B C
The traction grades, from highest to lowest are AA, A, B, and C. The
grades represent the tire's ability to stop on wet pavement as measured
under controlled conditions on specified government test surfaces of
asphalt and concrete. A tire marked C may have poor traction
performance.
The traction grade assigned to this tire is based on
straight-ahead braking traction tests, and does not include
acceleration, cornering, hydroplaning or peak traction characteristics.
Temperature A B C
The temperature grades are A (the highest), B and C, representing the
tire's resistance to the generation of heat and its ability to dissipate heat
when tested under controlled conditions on a specified indoor laboratory
test wheel. Sustained high temperature can cause the material of the tire
to degenerate and reduce tire life, and excessive temperature can lead to
sudden tire failure. The grade C corresponds to a level of performance
which all passenger car tires must meet under the Federal Motor Vehicle
Safety Standard No. 109. Grades B and A represent higher levels of
performance on the laboratory test wheel than the minimum required by
law.
Maintenance and Specifications
297
Tire inflation pressure
Use a tire gauge to check the tire inflation pressure at least monthly
(check the tire inflation pressure in the spare tire every 6 months) and
before long trips. You are strongly urged to buy a reliable tire pressure
gauge, as automatic service station gauges may be inaccurate. Ford
recommends the use of a digital or dial type tire pressure gauge rather
than a stick type of tire pressure gauge.
Use the recommended cold inflation pressure for optimum tire
performance and wear. Under-inflation or over-inflation may cause
uneven treadwear patterns.
Under-inflation is the most common cause of tire failures and
may result in severe tire cracking, tread separation or9blowout9,
with unexpected loss of vehicle control and increased risk of injury.
Under-inflation increases sidewall flexing and rolling resistance,
resulting in heat buildup and internal damage to the tire. It also may
result in unnecessary tire stress, irregular wear, loss of vehicle control
and accidents. A tire can lose up to half of its air pressure and not
appear to be flat!
When weather temperature changes occur, tire inflation pressures also
change. A 10 degree temperature change causes a corresponding drop of
7 kPa (1 psi) in inflation pressure. Check your tire pressures frequently
and adjust them to the proper pressure which can be found on the tire
label or certification label.
If checking tire pressure when the tire is hot, (i.e. driven more than 1.6
km [1mile]), never ªbleedº or reduce air pressure. The tires are hot from
driving and it is normal for pressures to increase above recommended
cold pressures. A hot tire at or below recommended cold inflation
pressure could be significantly under-inflated.
To check the pressure in your tire(s):
1. Make sure the tires are cool, meaning they are not hot from driving
even a mile.
Note:If you have to drive a distance to get air for your tire(s), check
and record the tire pressure first and add the appropriate air pressure
when you get to the pump. It is normal for tires to heat up and the air
pressure inside to go up as you drive. Never ªbleedº or reduce air
pressure when tires are hot.
2. Remove the cap from the valve on one tire, then firmly press the tire
gauge onto the valve.
Maintenance and Specifications
306
