First published November 2006, updated June 2011

There's a common perception the tires we put on our vehicles are made of rubber, a renewable resource. Unfortunately, well over 90% of all tires are made from synthetics - and they have certainly proved to be an environmental headache.

Once tires have reached the end of their serviceable lives, they tend to be dumped in huge piles. If these piles should be set alight, the smoke is an extraordinarily toxic cocktail and the runoff from melted residue can contaminate groundwater.

Tires left sitting around in the open also collect rainwater and become perfect breeding grounds for mosquitos.

In the USA, about 300 million tires are scrapped or dumped per year. While there's been a lot of talk about recycling tires, 25% still wind up in landfills and nearly half of reclaimed tires in the USA are utilized as "Tire Derived Fuel" (TDF), usually burned alongside other fuels such as coal.

Burning tires creating huge amounts of air pollution, containing toxins such as:

- benzene (carcinogen)
- lead
- polycyclic aromatic hydrocarbons
- butadiene (central nervous system damage, carcinogen)
- styrene (potential carcinogen)
- dioxins
- furans

So unfortunately, taking tires to recycling centres mightn't be that earth friendly after all. Check with the centre that you go to regarding what happens to the tires they collect.

While tires are a necessary evil in our modern lives, there's some things we can do to reduce the number of tires that may wind up being used as a toxic fuel alternative or just dumped in landfills. You can also save some cash in the process.

You can extend tire life substantially by:

- checking to see if they are inflated to proper levels
- check inflation levels weekly
- don't speed
- corner, brake and start off gently
- ensure your tires are properly balanced and rotated regularly
- don't overload your vehicle.

Just an important point on tire inflation - temperature differences will affect pressure levels; even just during the span of a single day. If you check your tires in the morning, chances are the pressure level will be noticeably lower than in the afternoon. This doesn't mean that you should adjust inflation umpteen times a day; but it's why they should be checked regularly - as the seasons change, so will your tire pressure. This will also be the case when you travel from an area of low elevation to high elevation.  Aside from environmental and financial reasons, ensuring your tires are properly inflated is an important aspect of safe driving.

Tires can be recycled into more tires or repurposed for many other applications, including:

- insulation blocks
- building homes known as "earthships"
- drainage aggregate
- clean fill
- planters for tomatoes and potatoes
- floor mats
- belts
- gaskets
- shoe soles
- seals
- washers.
- garden edging
- compost bins
- retaining walls
- ute/truck mats

One of my favorite uses it the potato planter. Lay down a tire, fill with soil and plant a seed potato. When the potato has sprouted and the leaves reach higher than a width of a tire, then add another tire and put in more soil, covering the plant except for the topmost leaves. Repeat the process throughout the life of the plant and you'll have a huge crop of potatoes.

In regard to concerns about chemicals leaching from tires when used in such a way, it's my understanding that old tires aren't such a problem - new tires will offgas volatile compounds; but this decreases and stops over time; while it is in serviceable condition on the vehicle. So when using tires to grow potatoes, the older the tire the better it would seem.

Do you have any other tips for recycling or repurposing tires? Please share them below.