Automotive Smog Check Tips
It Happened To Him - It Could Happen To You
Once during routine service, the Author of this book ( James Halderman )
rotated the tires on a Pontiac Trans Am.
Everything went well and he even used a Torque Wrench to properly
Torque all of the wheel /tires Lug Nuts.
When he went to drive the car out of the Service Stall ,
he heard a horrible grinding sound. When he hoisted the car to invest-
igate, he discovered that the front wheels were hitting the Outer Tie Rod Ends.
( What he didn't realize is that both Rear Tires Diameter were larger than the Front.
That's how the Vehicle came Brand New from the Factory with Zero Miles on the Odometer. )
The 16" wheels had a different backspacing Front and Rear , therefore ; these
wheels could not be Rotated Front to Rear.
Tip : Always check replacement or Aftermarket wheels for proper fit before driving the vehicle.
And , the Drivers Door Panel Jamm will display the correzt size of Tires for this vehicle .
Automotive Principles Technology - James D. Halderman ( 1999 Edition )
https://www.sokule.com/blog/cbarkwell
The Vibrating Ford Van
A Technician was asked to solve a vibration problem on a Ford Van.
During a test drive , the vibration was felt everywhere - the dash ,
steering wkeel , front seat , shoulder belts ; everything was vibrating !
The Tech. balanced all four tires on a Computerized Balancer, even
though wheel weights were put on all four wheels and tires, the vibration
was even worse than before.
The Tech. rebalanced all four wheels, time after time, but the vibration
was still present. The Shop Supervisor then took over the job of solving
the mystery of of "The Vibrating Van". The Supervisor balanced one wheel/
tire assembly and then tested it again after installing weights.
The Balance was still way off !!
The Supervisor broke the tire down and found about 1 Quart of liquid in
the Tire !! Liquid wqs found in all four Tires ! . This is why the tires couldn't
be balanced, every time the Van stopped, the liquid would settle in
another location.
The Customer later admitted to using a Tire Stop Liquid in all "4" Tires !
Besides Stop Leak, another common source of liquid in the tires is water
that accumulates in the Storage Tanks of Air Compressors, which often
gets pumped into tires when Air is added. All air compressors storage
tanks should be drained of water reguraly to prevent this from happening.
Automotive Principles Technology - James D. Halderman (1999 Edition)
Is The Age of a Tire Important ?
Youbetcha !..The National Highway Traffic Safety Administration
(NHTSA) recommends that any Tire SIX YEARS OLD or older
should be replaced , regardless of Tire depth. This means that tires
that look almost like new but are 6 years or older should be replaced
because the NHTSA determined that age, not tread depth, was a
major contributor in tire failures.
Automotive Principles Technology - James D. Halderman (1999 Edition)
https://www.edmunds.com/car-care/how-old-and-dangerous-are-your-tires.html
https://m.tiretrack.com/tires/tiretech/techpage.jsp?techid=11
https://www.popularmechanics.com/cars/cars/a4047/how-old-are-yourtires-15441034/
The Author of this book was looking at a 3 year old vehicle
when he noticed that the Right Rear tire had a build date code
newer than the vehicle.
He asked the Owner, "How badly was the vehicle hit ? The Owner
stumbled and shuttered a little, then said,"How did you know that
an accident occurred ?" He told the Owner that the Right Rear
tire, while being the same exact tire as the others, had a date
code indicating that it was only One year old, whereas the original
tires were the same age as the vehicle.
The first "2" numbers of the DOT code on the Tire indicate
the week of the tires Manufacture and the last "2" digits
of the FOUR Digits indicate the Year the tires are manufactured.
The Owner immediately admtted that the vehicle slidon ice and
hit a Curb , damaging the Right Rear Tire and Wheel Rim. Both
the Tire and Wheel Rim were replaced and the Alignment checke.
The Owner then dropped the price of the vehicle $500 !
Knowing the Date Code help assure that Fresh Tires are purchesed.
It also helps Techs and Vehicle Owners determine if the Tires have
been replaced.
Automotive Principles Techology - James D. Halderman (1999 Edition)
https://www.sokule.com/blog/cbarkwell
Tire Tread Wear
Tread Wear - Tread wear grade is a comparison rating based on the wear rate
of a standardized tire, tested under carefully controlled cinditions , which is
assigned a value of 100. A tire rated 200 should have a useful life twice as long
as the standard tires.
Note : The standard tire has a rating for tread wear of 100. This vehicle has
generally been accepted to mean a useful life of 20,000 miles of Normal driving.
Therefore, a tire rated at 200 could be expected to last 40,000 miles.
Tread Wear Rating Number Approximate Number of Miles
100 20,000 miles
150 30,000 miles
200 40,000 miles
250 50,000 miles
300 60,000 miles
400 80,000 miles
500 100,000 miles
The tread wear life of any tire is affected by driving habits ( fast stops, fast cornering
can decrease tread life ), Tire Rotation or lack of Tire Rotations, under inflated, wheel
alignment, road surfaces and climate conditions will play a role in your Tires life.
Traction - Traction performance is rated by the letters AA , A , B and C.
AA is the best.
Note : The traction rating is for Wet Braking distances only ! It does not include
cornering traction or Dry Braking performance. The traction rating is only one of
many factors that affect wet braking traction, including air inflation, tread depth,
vehicle speed and brake performances.
Temperatur Resistance - Temperature resistance is rated by the letters A, B and C ;
with A being the best rating. Tires generate heat while rotating and flexing during
normal driving conditions. A certain amount of heat buildup is desirable normal
drivung conditions. A certain amount of heat buildup is desirable because tires
produce their highest coefficient of traction at normal operating temperatures.
Forexample, rare car drivers frequently swerve their cars left and right during
pace laps, causing increased friction between the tire and the road surfaces,
which warms their tires to operating temperature. However ; if temperatures
rise too much, a tire can start to come apart -the oils and rubber in the tire
starts to become a liquid !
Automotive Principles Technology - James D. Halderman
https://www.sokule.com/blog/cbarkwell
