Tired of Tires?
by Andrew Meblin, copyright April 1, 2023
The plant is called guayule, and despite sounding like a Christmas avocado dip, it can be used to make tires. Yes, automobile tires can be produced from the branches, bark, and roots. Bridgestone is the company investing in this row-crop to car tire venture.
Guayule, a row-crop from which tires can be made.
It is actually not as weird as it sounds, considering that rubber comes from trees. Vast tracts of French Indochina were planted with rubber trees in the period between the wars, 1920-1930. British interests harvested rubber from trees in Malaysia. According to historical accounts, French rubber plantations in Indochina had the effect of deforestation of huge swaths of land. It is a bit odd to think that planting trees resulted in deforestation, but the rubber trees need space to grow and produce high-quality sap.
Similar to the process of harvesting maple syrup, rubber precursor is collected from trees in Vietnam
By the 1900s, a German chemist with Bayer chemical company synthesized rubber from petroleum. The product soon found use in the manufacturing of tires. Today, tires are made from 19% natural rubber, and 24 % plastic polymer. Add in braided steel cord, and a bunch of other stuff and you get a hefty, sometimes awkward to handle, doughnut. Today an average car tire uses 7 gallons of oil, whereas a truck tire (think big rig) takes 22 gallons of petroleum to produce. Of the 32 million metric tons of rubber produced in the United States, about 20 million of that is synthetic, produced from petroleum, using some exotic-sounding names like styrene butadiene, and chloroprene.
No comment needed
According to the US Tire Manufacturers Association, USTMA, 335 million tires were produced and sold in 2021 in the United States. Of those, 216 million tires were replacements, meaning the equivalent of 216 million tires were retired (I am so sorry). Additionally 65 million truck tires (from pick-up trucks to semis) were replaced.
Old tires, a problem of disposal
Used tires are a waste disposal problem, but lately more are being recycled into new tires or other products. As I understand it, the metallic belts make the process of breaking down the old tires very difficult. Years ago I tried to use a reciprocating blade electric saw to carve up an old tire to fit it into my garbage can. It was a serious chore. Used tires are discarded in marshland, creeks and rivers, and on other people’s property.
A gun club once took in a large number of truck tires and placed them in the impact area of some of the shooting ranges. The tires were stacked in an interlaced pattern, with an angle of repose designed to retain the embankment, and then filled with soil. The bullets would penetrate the curved section of the tire, and then be captured in the soil for recycling. It didn’t work that way. Even with the reduced bulk from tread wear, the thickness of the truck tires, resisted the bullets, and sent some of them “right back at ya.” Since the bullets had been bounced back, the velocity of the returning bullets was not lethal. But still! The club incurred a great expense as it had to pay to legally dump the tires.
But not all of the tire is properly discarded; some of the tire just goes away, sort of. Tire replacement is called for when the tread has been reduced to 1.6 millimeters, or 3/50ths of an inch. Since most new tires are sold with tread depths of eight or nine millimeters, 5/16th or 11/32nds of an inch that means that a substantial amount of rubber is turned into a fine dust. The dust sits on the roadway and stays there for an eternity. Actually, no. Tire dust settles on the asphalt, and adjacent landscape, where rain removes it and deposits this dust into creeks, rivers, bays, and eventually the oceans.
Time to retire this tire, and retire the car
Is the tire dust inert? According to the science people, no. In an article in The Guardian, we learn that salmon die when exposed to water permeated with tire dust. Washington State University’s Jenifer McIntyre and her team were trying to determine what caused the death of salmon before they could spawn. They collected run-off from a road close to the stream and exposed salmon to it. Death. A motorized cheese grater applied to a tire produced shavings, which were then soaked in water. Yes, salmon were exposed to that water. Death.
McIntyre’s research seems to have narrowed down the toxicity to a rubber preservative, 6PPD. And tires are the second biggest source of micro-plastics in the ocean, exceeded only by your Lulu Lemon yoga pants.
On the east coast, at The Citadel, way back in 2014, biologist John Weinstein and his graduate students looked for micro-plastics in seawater. And they found plenty. But more than half the micro-plastics were from a source not readily apparent. These were microscopic, black, and tubular in shape. Testing water closer to the main road and found an even greater abundance of the cigar-shaped particles. Then it dawned on them; tire residue. This gets us back to guayule. Could the by-product of guayule tires actually be fish food? Wouldn’t that be cool?
Maybe edible tires are not such a great idea. Recently I pulled an electrical extension cord out of my garage. It had fallen off of its hook. Numerous tiny teeth marks and holes down to the copper told me the insulation was made out of soy. The same problem exists with automotive wiring. Soy and squirrels, and/or rats eat the insulating “rubber” because it has some residual food value, or so the rodents perceive. Heck, maybe it just tastes good. Where I live now, bears routinely open unlocked car doors, and rummage for food. Can you imagine bears just start eating tires off the cars?
So, since tires are ubiquitous, and the automobile is vital for our daily commuting, and delivery of goods, what is the solution? In the short term, creating catch basins off of major thoroughfares, as have been constructed on portions of Interstate 80 near where I live. Would the soil adjacent to these catch basins be mined to remove the micro-plastic particles from the environment? Maybe a more high tech recapture system could actually result in recycling of the micro plastics. Instead of poisoning fish, we might reduce the energy required to manufacture tires, by catching the run-off from freeways.
Top, Image from ABC7 (San Francisco) report on side-shows; Bottom, another responsible use of tools
Given the proclivity of our young adults to engage in “side-shows”, which involve the gross destruction of automobile tires in a display of excessive risk-taking and disdain for the environment, maybe we are fighting a losing battle. A “side-show” involves a disorganized and random exhibition of spinning doughnuts, and tires in cars as passengers sit on window sills, and spectators venture forth into the clouds of tire smoke, to place themselves close to the lurching vehicles.
I worry about the health of those young people as they age, with tiny tubers of tires in their lungs. I mentioned that concern to my students at Richmond High School on several occasions, and many nodded in acknowledgement of the potential health risks. One student pointed out that since his face and hands had been coated with black particles after watching a “side-show”, it stood to reason that dust had also been inhaled. N-95 masks?
Presumably magnetic levitation on an industrial scale is still a long way off. Or is it? In the 1860’s balloons were used in the American Civil War, and it was less than fifty years later that heavier-than-air, powered flight came to be. The way technology advances, how long until tires, and indeed road surfaces, are no longer going to be a source of concern for humans?
https://www.nationalgeographic.com/environment/article/tires-unseen-plastic-polluter?loggedin=true&rnd=1680315112442
Re-caps! I remember watching that process in East Palo Alto. Recaps were accused of failing more often, but the recap industry organization conducted a "study" and its results showed that most of the "gator backs" (tire treads) on the highway were from new tires. Of course, new tires were more prevalent, so...
Tires paid for my Chico State education. I worked at a tire store in high school and DVC JC. We even “re-capped” old tires right there in the middle of Lafayette, Ca. We added an interesting aura between KFC and Mr Steaks!