Tire Safety And Age: How Old Is Too Old?

When thinking about tire safety, it is important to consider two things: age and use.  Vehicles driven daily are typically driven 15,000 miles a year.  But there are situations where cars put on even fewer miles. 

This includes: being driven only on the weekends, never driving in the rain, “show” cars, and cars that are stored for extended periods of time.  So, some tires on these types of cars put on less than 100,000.  But it doesn’t mean that they are safe tires.  

Tires deteriorate over time and can “age out” wear out before they wear out.

In a statement from the British Rubber Manufacturers Association (BRMA) issued on June 5, 2001 regarding the age of tires they state, "BRMA members strongly recommend that unused tires should not be put into service if they are over 6 years old and that all tires should be replaced 10 years from the date of their manufacture."

Tire age can be accelerated by a variety of environmental factors, such as sunlight exposure and coastal climates.  Poor storage and infrequent use of your vehicle are other things that can accelerate tire age. 

If you keep your tires in ideal conditions, the tire age can go as high as 10 years from its manufacture date.  But ideal conditions are the exception rather than the rule. And the worst part is that you cannot tell the safety of an old tire just by looking at it since there are no conclusive tests for the safety of tires without destroying the tire itself!

Due to this, some European car manufacturers of high performance sports cars, coupes and sedans have hedged their bets, stating in their owners manuals that the tire age should reach no higher than 6 years.

How Better Rubber Makes Tires That Are Safe

There have been a lot of changes in rubber compounds since Charles Goodyear discovered how to cure rubber when he baked a combination of natural rubber and sulfur on his family’s kitchen stove.  Thus, he would convert an unappreciated raw material into many useful products.

Goodyear cross-linked sulfur with polymers that, when exposed to heat, would help make rubber durable and at the same time maintain its elasticity. The main focus of new research has been finding tire age inhibitors.  Sulfur molecules are one such tire age inhibitor that is reactivated every time they are exposed to heat, making the rubber harder.

Nowadays, rubber in tires has oil in it that tends to migrate into the tires’ under tread/casing and evaporate into the air. In the process of this, the tire compound releases oil and gets harder.  If you can’t quite visualize this, go into any tire store and take a big whiff.  You’ll smell the oil there.  

Before curing, most tires are coated with a mold release agent that is makes it easier to remove from their mold after curing.  If it’s a little hard to visualize, think about spraying “Pam” on a fry pan before pouring on the batter for pancakes.   

This increases the safety of tires because some of the mold release agent gets “cooked” onto the surface of the cured tire, which prevents all the oil from evaporating.

What Is The Right Tire Age?

In most cases, most street tires are good for 6-8 years if maintained properly. Don’t forget though that this includes the time the tires spent from the manufacturer’s plant to the dealer to you.  So, keep this in mind when you are determining tire age. 

Most tires get to you anywhere between 3-6 months.  Some stay longer with the tire manufacturer, but generally all tires that go on your car are less than a year old.  So, you should not get an old tire from any tire manufacturer.

Which Tires Last Longest?

If you want to buy a tire based on how long it will last, you have to consider thread compound.  The more aggressive its compound … the shorter tire life. Below is a list of tires from longest-lasting to shortest-lasting:

• Max Performance tires
   
• Ultra High Performance tires
   
• DOT legal competition tires

Bottom line: if you want to avoid safe tire issues go with tires that last long and properly maintain them.