How Long Do Tires Last?

Here's a question that came up recently in a Madison rewrite and reminded me of a similar question in Earth Abides. How long do rubber tires take to decompose? How long are they usable?

Naturally, these are two different questions.
1. How long does rubber exist as a discrete compound?
2. How long do rubber tires hold air and maintain their integrity?

The guys at Tire Tech Information present findings from several manufacturers. To quote:

"How many years will tires last before aging out? Unfortunately it's impossible to predict when tires should be replaced based on their calendar age alone."

Many things contribute to the wear of tires including usage, environmental conditions, sunlight and pollution. For instance, going at top speed may wear out the tires, but not using them at all may also damage them. Living near the ocean is bad for tires, but so is living in places with lots of air pollution. I would guess that driving or parking near industrial areas would be bad for tires. You should see the cars driven by paper mill employees in my town. Hardly a lick of paint is left on the hoods of these cars. Imagine what it does to the rest of the vehicle.

The British Rubber Manufacturers' recommendations as quoted by Tire Tech:

"Environmental conditions like exposure to sunlight and coastal climates, as well as poor storage and infrequent use, accelerate the aging process. In ideal conditions, a tyre may have a life expectancy that exceeds ten years from its date of manufacture. However, such conditions are rare."

In Madison, usable tires are hard to find but still available. This is Oregon, one of the sweetest climates for automobiles. No salt on the roads, no excessive heat. Very little sunshine (not today, thank goodness). So I push for the upper end of tire usability—ten years and a little after.

Since bicycle tires aren't as heavily bonded to other materials, are easier to maintain, and their use isn't as extreme, I would guess they last more than ten years.

Rubber itself lasts a very long time. In fact, we don't know exactly how long it lasts or when it decomposes, since we've only been throwing it in our landfills for a little over a hundred years. This is a good reminder when visualizing what's left in the PA world. Evidently, tires will be breeding mosquitoes in ditches and junkyards forever. Think about the reefs that were supposedly "stabilized" with old tires. The stupid things are still there after decades, grinding away all life. Go here to read what recyclers say about tires.

I had a very kind and thoughtful rejection from an agent today—timely too, if anyone's paying attention. It's given me a lot to think about, and I may have more to say such things later. In the meantime, Yola is holding forth on her blog, cracking the whip and being generally disgraceful. Go kiss the ring and debase yourself in whatever way you think she'd like.