Let’s be honest: Tires make the world go round. Unless you’re a professional speed walker, your method of transportation probably involves tires of some sort.

But these tires don’t last forever. Whether it’s an irreparable flat or loss of tread, eventually tires need to be replaced. Some tires can be retreaded for a second life, but what happens to those that are due for disposal? Let’s break down the ins and outs of recycling and properly disposing of your worn out wheels.

The Great Rubber Mountain
If you don’t see value in recycling tires, let us introduce you to the concept of stockpiles, acres of tires stacked by the thousands in one concentrated area.

Tires on a truck
IN THE U.S., 920 MILLION TIRES WERE USED FOR NON-COMMERCIAL VEHICLES ON THE ROAD IN 2005. ON AVERAGE, 290 MILLION TIRES ARE DISPOSED OF EVERY YEAR.

Tire stockpiles can lead to a number of unpleasant situations:
They are breeding grounds for mosquitoes and vermin, especially when they are filled with rainwater.
They are prone to catching fire. Since tires are made largely of oil, they are difficult to extinguish (some can last for months) and produce an acrid, black smoke.
Stockpiles are of such concern that states must spend money to clean them up, and there are businesses that focus solely on collecting tires for recycling.

Fuel ‘er Up
The EPA estimates that 45 percent of all scrap tires are burned for energy, also known as tire-derived fuel (TDF). Since the average tire contains five gallons of oil, they can generate comparable energy to crude oil or coal.

More than 40 percent of TDF goes to cement kilns, but other uses include paper factories and electric companies. This means that keeping tires out of landfills affects the ground you walk on, the paper you write on and the lights in your home and office.

The trick with TDF is that tires must be shredded first since whole tires would be too large for a furnace. Shredding recovers much of the metal in a tire, such as a rim and lead weights used for balance. The metal can be extracted and recycled, leaving crumb rubber to use as fuel.

The Dirt on Disposal

There are ways that tires can be recycled into new products, and most of these uses take place after shredding since there is more demand for crumb rubber than whole tires.

Crumb rubber can be used as the surface for playgrounds because its soft padding helps prevent injuries. However, there has been recent debate over this use because of the potential toxins that tires may release, including lead and mercury.

Shredded tires are also used as an additive for playing fields since they provide a strong retaining wall that improves drainage. This leads to stronger grass and a reduced chance of field-related sports injuries.

Tires even have a purpose in construction, because rubber tends to absorb sound. Rubberized asphalt can be used to make longer-lasting roads that produce less traffic noise and is popular in many states. Its absorbing qualities also make it ideal for running tracks, causing less stress for legs.

Lastly, tires can be recycled into new tires by converting them back to synthetic rubber. This is not a common solution because of the cost involved. But in the future with improved technology, it could be a more mainstream solution.

The Next Time You Get a Flat

The most important question still remains: How do you actually recycle tires? For starters, many retailers that sell tires will accept a limited number when you make a purchase. If you’re in the market for new tires, be sure to ask if recycling your old ones is an option.

Your state may also have a waste tire plan, which would be headed by your state environmental department. Many states require recyclers to file for a permit to accept tires, so they will also know of locations that accept tires for recycling.

If you can’t find anywhere to dispose of your old tires, consider a way to reuse them. You can build a tire swing for the kids, use them as a planter in your backyard, or even build a house!