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Tires are round, tires are black, we all need tires that don't go flat.

With all of the Firestone tire problems becoming bigger every day, I figured that some people might not know that tires are embossed with a wealth of information.

A brand name does not imply quality. Tires seem to fall into the category “my brand is better than your brand” as GoodYear, Michelin, Firestone, Kelly, Continental, and all the others spend millions in advertisement dollars to convince the busy consumer that their brand is your best choice.

Given that tires are generally of a high quality, how does an informed consumer shop for a tire?

The most important tire buying factor is size. Look on the trunk lid or the driver's side door jam and purchase tires that are the same size as the one listed on the sticker. The ONE listed on the sticker. You will not see a choice.

Location …… Speed …..Pressure
Front (FRT)
P205/55R15 ……...S……..32psi
Rear (RR)
Spare (SPR)
T125/70D15 ……...F……..60psi

Changing the size will effect the speedometer (accuracy), traction, suspension, cornering, handling, and loading capability of the vehicle. I do not recommend the popular low profile tires.

The second most important item is the tire's Date of Manufacture. This one is tough. We go into the store, some saleman (PC-Salesperson) writes you up a ticket for tires, you pay $554.23, then you go to the waiting room because you are not allowed into the bay - insurance reasons - and then you are called when you car is ready. It's magic.

I hate that and do not go to places where I cannot talk to the technician directly. (a.k.a. dealers).

Well, if you go out to your car, look at the tires before driving off, and see that they are three years old, what are you going to do. You are going to wait until another bay comes open and they will replace the tires –right?

No. you are going to inspect the tires before they go on the car. That right! As much as you do not like it, you will look the tires over before they go on the car. You are not going to see the inboard sidewall (all the way around) again for a long long time. Look at them now, smell the newness of the rubber, feel the tread for uniformity, at least act as if you know what you are doing. Look for blemishes. Demand a discount if you suspect a second or send one back like a bad bottle of wine; you are the connoisseur. At the very least you will know what they are suppose to look like when you see improper wearing later on.

What are all those other things stamped on the tire?
Well there is the white wall lettering which means your smart for buying GOODYEAR XZY tires.
Of course, I am kidding you. I like the White Lettering out and Whitewalls on older cars.

Get out you Captain Crunch Decoder Rings:
Here is the key to the secret tire codes;
P205/55 (R) 15 (88V) (A1 324) XGT V
[Code][Width]/[Aspect][Construction][Size] (Load Index & Speed Rating)(DOT#)[mfg code designation)

Code: Example P
P = Passenger
LT = Light truck
T = Temporary
LTP = Light truck, personal use

Width: Example 205
Width at widest point, sidewall to sidewall, in millimeters

Aspect Ratio: Example 55
Tire height in millimeters, measured tread to bead, divided by width above, multiplied by one hundred. Damn algebra.

Construction: Example R
R - Radial ply
B - Bias belted
D - Diagonal bias

Size: Example 15 (Note; always in inches)
The diameter of the rim needed to mount to.
Not the tire diameter.

Load Index: Example 88 [Ranges from 65 –104 = 639 lbs – 1984 lbs]
80 - 992 lbs
88 – 1235 lbs

Speed ratings: Example V
(The maximum speed the tire can maintain at its maximum load rating)
Ranges B – ZR = 50 – 150+ mph
B - 50 mph
Q - 100 mph
R - 106 mph
S - 112 mph
T - 118 mph
U - 124 mph
V – 150 mph
H - 130 mph
V - 149 mph
W - 168 mph
Z - more than 168 mph

Free spinning tires, tires spinning without a load, will self destruct over 35 mph.
That is why computer spin balancing is not run at a high speed or for very long.

DOT Serial Number Example (A1 329)
Michelin, Poitiers, France 32nd week of 1999.

The last three digits show the year and week that the tire was manufactured. Hopefully, it will not be too difficult to tell the difference in a tire made in 1989 from one made in 1999. Especially, since the format for displaying, the information has changed. The old method looks like (205/60HR15) where H is the speed rating.
Tires suffer from sunlight, ozone, and aging deterioration.
You should not settle for a tire that is two years old or older.

Manufacturing Code Example XGT V
This mean nothing to anyone except the manufacturer.

Other items on the tire wall;

Maximum Air Pressure - This is the max pressure the tire is designed to hold
(note this is more than the recommended inflation pressure)
Do not inflate to this pressure.

Maximum Load
Weight the tire can support. You do not have to have an index with you.

Tread Wear Index
A rating of the tire's resistance to wear.
100 is the reference.
250 rating indicates 2.5 times the wear resistance of the reference tire.
This number cannot be accurately translated to mileage.
Means nothing to the consumer.
Look at the guarantee; 80,000 mi, 60,000mi, 40,000 mi. That will tell you the tire mileage.

Traction Index
A rating of the tire's ability to stop on wet pavement.
There are three grades, A, B, and C, with A being the best.
This index does not reflect the tire's traction performance on dry, snowy, or icy pavement.

Temperature Index
A rating of the tire's ability to dissipate and resist heat.
There are three grades, A, B, and C, with A being the best.

Plant codes; too many to list

So, are you going to go down to the store and just get some tires? Probably. Just understand, like all things, tires are not simple. How many lost their lives in this Firestone fiasco? Make sure your tires are properly inflated.

Remember where the rubber meets the road is only the width of you palm. (Size 8).
Motorcycles = a pack of cigarettes.
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