Tire Aging Alerts
With the summer months upon us one of the main concerns drivers should have is for their tires. When tires fail, the result can be devastating injury and even death. The most common results of a high speed tire failure include rollovers , collisions, loss of vehicle control and post collision fires.
Tires can fail for a vast number of reasons including:
- Uneven tire tread wear
- No printed expiration dates
- Manufacturer defects
Checking for Uneven Tire Tread Wear
Tires are built with wear bars (flat spots) that can be found in the tread grooves. These wear bars are there to visually indicate wear. If the tire tread is worn down so the flat spots are flush with the surrounding tread, this indicates the tire is worn out and should be immediately replaced. If cords are showing through the rubber, the tire is not only unsafe to drive on but most likely on the verge of failure. If a tire has bulges, deep cracks or the tread is separating from the casing this can also indicate impending failure.
Tread wear is most easily measured by using a penny. Place the penny with Lincoln's head upside down in a groove between the treads. If you can't see the top of Lincoln's lead, the tire is okay and still has some wear left in it. If the top of Lincoln's head is flush with the tread, the tread depth is 2/32-inch (1.6mm) or less, indicating the tire is worn out and needs to be replaced.
Some experts now say the same test should now be done with a quarter. If the top of Washington's head is flush with the tread when you place a quarter upside down in a groove, the tread depth is 4/32-inch (3.2mm). Though the tire still has some tread wear left, braking, traction and handling are significantly reduced compared to a tire with more tread on it.
Because of this, many experts now recommend replacing tires when the tread depth is worn down to 4/32-inch or less.
Tire Expiration Dates
The Rubber Manufacturers Association , explains tire expiration dates may be hard to determine because there are numerous factors that can affect tire aging.
Many tire experts believe printed tire expiration dates would be worthwhile. Tire manufacturers worry consumers won't pay any attention to an expiration warning anyway and would not replace old tires with new ones. The concern among industry insuders is that people may think the tire industry is trying to pressure the public into buying more tires by stamping an expiration date on them.
Tire makers say expiration dates would complicate their distribution systems because new tires often sit on shelves for two years or more. Tire industry manufacterers say tires vary in chemical makeup, so one expiration date would not fit all tires. The National Highway Traffic Safety Administration says additional research is needed to come up with an appropriate aging test for tires.
Translating Tire Date Codes
What's the best way to determine the age of the tires on your vehicle? Look at the last group of digits in the DOT manufature code on the sidewall of your tire, these numbers indicate the date of manufacture. The number usually is stamped in a recessed rectangle. This DOT code indicates the tire manufacterer, the tire's date of manufacture and place of origin. The last group of digits in the code is the date code that tells when the tire was made.
Before 2000, the date code had three digits. Since 2000, it has had four. The first two digits are the week of the year (01 = the first week of January). The third digit (for tires made before 2000) is the year (1 = 1991). For most tires made after 2000, the third and fourth digits are the year (04 = 2004).
The date of manufacture is essential information for car owners and tire buyers because tires deteriorate even if they are not used. European automobile manufacturers recommend replacing ANY tire that is more than six (6) years old, including the spare tire. No such recommendations have yet been made by domestic vehicle manufacturers.
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Rob Ammons is Board Certified in Personal Injury Trial Law by the Texas Board of Legal Specialization, in addition to being Board Certified in Civil Law by the National Board of Trial Advocacy. Rob Ammons’ law practice, The Ammons Law Firm, is located in Houston, Texas. The Ammons Law Firm practice is exclusively personal injury law, handling such cases as: tire defects , oil rig explosions , truck accidents , plant explosions, refinery accidents, wrongful death , post-collision fires , seat belt defects, airbag defects , SUV rollovers and workplace accident injury.
How To Read A Tire Sidewall