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9.0 SIMPLE EASY AUTOMOBILE REPAIR AND MAINTENANCE BY DON PATTEN
By
Don Patten
Don
Patten is a leading expert in automotive education. His text book Automotive Service
Basics published by Prentice Hall is used in automotive instruction courses world
wide.
9.0.1 SIMPLE CAR MAINTENANCE CHECK YOUR TIRES AND SAVE MONEY; AUTOMOBILE REPAIR AND
MAINTENANCE
By
Don Patten
Don
Patten is a leading expert in automotive education. His text book Automotive Service
Basics published by Prentice Hall is used in automotive instruction courses world
wide.
Tires
have several important jobs; they hold up all the weight, make road contact, and help stop
the vehicle. They work under extremely harsh conditions and if neglected will fail
rapidly. Tire maintenance is important from the standpoint of both safety and economy. One
of the items checked when an accident occurs is the condition of the tires on each vehicle
involved. If the tires are not legal, the vehicle owner could be held liable and forced to
share responsibility for the accident no matter who was originally at fault. Improper tire
maintenance can be the direct cause of certain types of accidents. Reduced vehicle
response, uneven braking, loss of road contact, pulling from side to side, separation of
the tire from the rim, and uneven tread wear are some problems caused by improper tire
maintenance. At this point, lets walk through a complete inspection and service of the
tires. Here's what to look for and why.
==
1. Check the cold inflation of each tire. Do this with a tire gauge. These are inexpensive
and available at most local parts or automotive chain stores. Refer to the vehicle
operation manual or the tire inflation decals placed on the drivers side door edge or
glove compartment door. This will give you a good starting point. Inflate each tire to the
correct pressure. Carefully inspect the tires over a period of time and mileage to
determine if any abnormal wear is showing on the tread. Tire tread wear is the final
determining factor on how much tire pressure is correct. An over inflated tire will show
excessive tread wear in the center. An under inflated tire will wear on both the outer and
inner edges and leave the center tread. Correct tire pressure will result in even tread
wear across the tread width. Start at the recommended pressure and either increase or
decrease pressure until normal wear is achieved. Always use tread wear as the deciding
factor on what the correct pressure should be for your vehicle.
==
2. Make a complete tire inspection. Look for uneven wear between the tires, inside or
outside tread wear, cupping wear on the tread, sawtooth tread wear, nails or glass in the
tread, tire separations and defects, sidewall cuts and defects. It is better to raise the
tire off the ground but if this is not possible, move the vehicle enough to inspect each
area.
==
3. Look for tire wear indicators. Built into the tread are bars that will show up when the
tread is worn down to an unsafe level. This will show up as a straight line across the
tread width. Tires worn to this condition are not legal to run in most states.
==
4. Make a road test. As the speed increases check to see if there is any vibration or
movement of the steering wheel. Tires that vibrate should be balanced.
==
5. Perform a bent rim check. Spin the tire and look for a side to side movement of the
tire which indicates a bent rim.
==
6. Rotate your tires on a regular schedule. The tires should be rotated according to the
manufacturer's recommendations to achieve maximum tire mileage or wear. 40,000 mile tires
should be rotated at least twice during the forty thousand miles. If you have a regular
tire for a spare, you can use a five tire plan. Most vehicles will be restricted to a four
tire plan because the spare is a "space saver" and not to be run except in an emergency.
Always have the tire balance rechecked when they are rotated.
==
7. Know the signs of alignment or worn parts problems. Saw toothed wear usually means
either cornering wear or toe-in problems. Inside or outside tread wear should be checked
out on an alignment machine. Camber ( the inward or outward tilt of the tire at the top)
is the primary cause of this condition. Worn front end parts can cause cupping. Excessive
caster alignment can cause vibration or pulling to the right or left. Alignment should be
corrected when the tires show wear, or on a regular schedule of at least once a
year.
==
8. Check the torque (correct tightness) of the lug nuts. Failure to correctly torque lug
nuts is one of the primary causes of warped rotors and drums. This will result in pedal
pulsation when the brakes are applied.
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