The Hidden Life of tires

By Jennifer Hattam

At the dawn of the automotive age, it wasn’t uncommon for motorists to carry six spare tires on a long journey. Thanks to poor design and bumpy roads, the average driver in 1900 chewed up 37.5 tires each year. Although both tire quality and roads have improved dramatically over the past century, tires still don’t last forever. Americans discard some 280 million annually, creating serious problems.

Many of these scrap tires are "recycled"—but that often means they are burned for fuel in a cement kiln, paper mill, or industrial boiler. About 115 million tires are incinerated every year, a dirty process that can generate benzene, toluene, methylene chloride, PCBs, dioxins, and other toxic chemicals. Only 80 million tires are actually reprocessed into new products, mostly in civil-engineering applications like exit-ramp embankments and cushioning for roads.

That leaves nearly a third of all old tires to be landfilled, stockpiled (due to landfill restrictions or prohibitive disposal costs), or illegally dumped. Some 300 million to 500 million are strewn around the United States. Stacked on top of each other, they would reach a quarter of the way to the moon.

Tire piles aren’t just unsightly; they’re unhealthy. Made primarily of oil and rubber, tires are flammable. Once a pile starts burning, it traps oxygen, making the blaze difficult and expensive to put out. A large tire fire can smolder for up to a year and spew millions of pounds of contaminants into the air. A tire’s curved shape also readily collects rainwater, creating ideal breeding conditions for bugs and vermin. The Asian tiger mosquito, an invasive species that carries encephalitis and dengue fever, spread into 17 states within two years after its initial 1985 sighting—in a Houston tire pile.

Tires take their toll while in use, too. The average tire sheds about a pound a year of tiny rubber particles into the air, soil, and water. This particulate pollution has been implicated in rising rates of asthma, now the most common chronic childhood disease in the United States.

What Next?
BUY THE BEST Since 84 percent of scrap tires are generated by passenger cars, drivers’ choices can make a difference. Better tires last longer, saving you money and lessening your environmental impact. A tire with a high tread-wear grade such as 400 should last about twice as long as one from the same brand graded at 200.

Another thing to look for is a manufacturer’s mileage warranty: Coverage for 80,000 to 100,000 miles is considered good. Replacement tires should be the same size as the originals: Tires even 10 percent too small for the vehicle can wear out significantly faster.

DRIVE SAFELY Regular maintenance and good driving habits can double a tire’s life span—halving the number of discards—while conserving fuel. Simply inflating your tires to the proper level can increase gas mileage by 3.3 percent. Check tire inflation at least once a month, or before every long trip. When out on the road, avoid potholes and fast starts, stops, or turns. Driving above normal highway speeds will reduce gas mileage and deteriorate tire rubber more quickly.

RETREAD Once common nationwide, retreading tires (instead of replacing them) fell out of favor as the price of both oil and tires plummeted. But truck, bus, aircraft, and fire-engine tires are still regularly and safely retreaded, and yours can be too. Since a retread replaces just the outside, reusing the body, it requires 70 percent less oil and energy than producing a new tire. The Tire Retread Information Bureau lists dealers who do retreads at www.retread.org/guide.

RECYCLE If retreading isn’t available in your area, make sure your tires are sent to reprocessing companies that will give them a second life in other products. Ask your tire retailer about its policies; if it doesn’t recycle this way, call your local solid-waste-management or sanitation department for proper disposal instructions. (The EPA lists these agencies at www.epa.gov/epaoswer/non-hw/muncpl/states.htm.) Then close the loop by buying recycled goods. The Rubber Manufacturers Association lists companies that use recycled tires in everything from purses to garden hoses at www.rma.org/scrap_tires/scrap_tire_markets/recycled_catalog.cfm.

ON THE WEB
The EPA factsheet "Your Car (or Truck) and the Environment" (www.epa.gov/otaq/consumer/car-env.pdf) contains extensive tips on buying and maintaining tires. The Rubber Manufacturers Association also offers safety and maintenance advice (www.rma.org/tire_safety/tire_maintenance_and_safety). Of course, if you drive less, you’ll need to worry less about tires. Just another reason to put down the keys and stroll to the store once in a while.

Jennifer Hattam is Sierra’s associate editor.