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Tire life is usually indicated by something called tread life, or tread depth.
Tread depth is the length of tread left on the tire. Tread is the rubber left on the outer part of the tire, which is usually called the tread face.
The tread on a tire will deteriorate or simply go away as you drive. This rate of tread disappearance is tire wear rate or tread wear rate.
The rate at which your tread wears and tears is the length of time you can drive on your tire.
Tread depth is usually measured in 32nds of an inch. And a new tire comes with about 10/32 of tread on them before they are driven.
As a tire is driven on, the rate of tread disappearance is about 1/32 for every 5,000 to 8,000 miles. This is usually how a tire ‘dies’ and is considered no longer usable.
How Does A Tire Die If It’s Never Driven On?
A tire dies if it’s never driven on by drying out. Tire manufacturers place oils in the tire that lubricate the rubber innards of the tire when they are driven on.
When a tire’s tread never hits pavement, or is not driven on for long periods of time, this oil never gets a chance to reach the rest of the rubber in the tire and the tire dries out.
As a tire’s rubber ages and the rubber is exposed to oxygen for long periods of time, the tire becomes stiff and can crack when used. This cracking can cause the cords in the tire to start separating and lead to tire failure.
How Should Tires Be Stored?
There are a couple ways to smartly and intelligently store your tires instead of just stacking them in your garage.
If you just stack them, you will have to replace tires quicker than you would if you just stored them correctly.
- Store tires in a cool, dry place, directly out of the sunlight. Storing them where sunlight can hit them will affect the rubber compounds in the tire and cause the car tires to age quicker than normal.
- Keep tires away from heat sources such as radiators and vents and away from chemicals like gasoline and oil. Fumes and heat waves can greatly affect the rubber compounds and affect the tire’s shelf life.
- Store the tires away from sharp objects and abrasive surfaces as these can damage the car tires.
- Tires should be stored on their sides, and not stacked on top of each other as stacking them can cause them to become misshapen. At a tire shop you may see them stacked, but this is because they are about to be thrown away.
- Use a protective converting in order to keep dust and debris away from your tires.
Driving On Old Tires
Like most tires, old tires provide traction to the vehicle. Whether the old tires were new when you stored them or used, as long as they have ample tread and are less than 5 years old, you should not notice any difference driving on them.
Driving on stored tires is no different than driving on tires stored in a shop for a couple months.
That’s because a tire’s chemical makeup doesn’t start changing until around the 5th year.
And the chemical change up of a tire might even be the same after the 10th year if the tire is stored properly according to some experts.
“Well what about winter tires?” you might ask, since they have different rubber compounds than most tires.
Well the answer is the same. The oil that tire manufacturers place into the tire are good to be stored unused for around 5 years.
Should Or Shouldn’t You?
Should you drive on tires stored more than 5 years? Well according to some experts, it’s ok to drive on tires stored more than five years.
According to others, it’s not ok to drive on them. In my opinion, it’s up to the owner of the tires.
Do some tests on the tires yourself to see if the stored tires seem safe. One test you can do is to hold the tire up as high as you can go and drop it on it’s tread face and see how resilient the rubber is.
If the tire doesn’t bounce and respond like a set of new tires would, consider trashing the old tires and buying a set of new ones.
Do a visual inspection of the tires. If the rubber seems to be corroded and there’s metal sticking out of the tires, do yourself a favor and trash the stored tires.
But if everything seems to be in good working order, take them to your mechanic and put them on and go for a small drive to see how they handle.
Drive around a parking lot and do some quick cornering tests and see how the tires handle.
They may not handle like new tires you just purchased off Tire Rack, but if they get the job done, you should be able to use them.
There’s no reason as to why you can’t other than obvious visual failures or performance based failures.
Seeing a set of aging tires will be quite apparent to the tire owners.
Not only will there be cobwebs in the center of the tire, but there will be cracking in the side wall, and they will feel stiff.
The tire will almost look soggy and you will know right away that this item is not safe to put on your car. It would be an innate response to the condition of the tire.
There are some common signs to look out for such as dry rot and cracking, but once again, once you see these signs and symptoms you will know right away not to put these items on your vehicle.
Tire aging happens because the oil in the rubber dries out and cannot lubricate the rubber it’s supposed to so the soggy look comes from the tire drying out and looking as if it just came out of a swimming pool.
It will also feel as if it is inflexible and hard to the touch. When you press down on the tire it will show no signs of flex and will almost start to feel like it’s crumbling.
About The Author
Christopher Sparks has been servicing vehicles since 2012. After completing the automotive studies program at Camden County College, he was awarded an Associates's Degree in Applied Science. His first job was a lube-tech at Jiffy Lube, and is currently an independent B-Technician servicing vehicles for the United States Postal Service. Christopher is ASE certified and loves rebuilding engines.Read more about Christopher Sparks