Environmentally Friendly Tires
With billions of vehicles on the road right now, the environmental impact of personal transportation is huge. Most of the focus in the automotive industry has been on making the engines cleaner and more sustainable. But what about the things that wear the most, the tires?
Increased Automotive Sustainability
The increased sustainability of the automotive industry has primarily been achieved through the use of electric motors, hybrid gasoline/electric engines, hydrogen fuel cells, and many other combinations intended to reduce or eliminate emissions from their propulsion systems.
But what about the tires? The one thing all road-going vehicles have in common, regardless of their engine, is a set of rubber tires that carry the vehicle’s weight and help it adhere to the road’s surface. They have a significant impact on the performance, safety and efficiency of the car. In the case of electric or high-efficiency vehicles, the tires are designed for as low of rolling resistance as possible, intended to help the EV eke out the most distance possible from every kWh battery capacity it has.
Historically, tires have been made with natural rubber compounds, but in recent years the technology of tires has increased to the point that some contain hundreds of compounds and components intended to increase lifespan and safety. They are high-tech and expected to deliver us safely to our destinations on dry roads and in wet or snowy conditions and last for thousands of miles before they wear out.
Toxic Chemicals Found
But they do wear out. Friction from the hot roads of summer and varying surface conditions means that the average set of tires will only last a car owner three to five years. The road’s surface grinds away at the tires in turns and braking. All that material makes its way into the environment, often ending up in ditches or storm drains, leading to rivers and other aquatic habitats.
Recent research by the University of Lethbridge shows that some of the compounds in tire dust are toxic to fish. The study found that sloughed-off particles contain a chemical compound called 6PPD, which becomes 6PPD-quinone when it interacts with ozone. 6PPD-quinone is toxic to various fish species, including trout, char and salmon. Research is ongoing to determine which species are vulnerable and what concentrations affect them.
Sustainable Tire Alternatives
Thankfully, the major tire manufacturers are taking sustainability seriously. Many are currently reformulating tires to take advantage of new knowledge in natural components that can provide the same safety and anti-wear properties to the finished tire but by using compounds derived from natural sources that are less toxic to the environment.
According to Goodyear, 17 sustainable ingredients in their newest formulations include things like recycled polyester and plant-based components like soybean oil, rice husk waste, and “bio-renewable” pine tree resin. It also uses steel with “high recycled content” and “ISCC-certified mass balance polymers from bio- and bio-circular feedstock.”
This area is also a focus of a dedicated program at Michelin. Known as the BioButterfly project, research is being conducted with industry partners and the support of ADEME (French Agency for Environment and Energy Management). The aim is to produce butadiene (an anti-wear compound) using ethanol derived from biomass to replace petroleum-derived butadiene, a key component in the synthetic rubbers used to make tires. According to Michelin, 4.2 million tonnes of wood chips could be integrated into Michelin tires annually.
Ultimately, it would be best if tires would never wear out or if humans could use some form of mass transit instead of cars, but that will never happen practically. We are addicted to the convenience of getting into a car and driving safely and economically wherever we need to go.
Vehicles like electric or hydrogen-powered cars will take care of the emissions from the engines, autonomous-assisted driving will reduce the need for higher speeds, and AI will direct us to more efficient routes. Now, bio-sourced compounds for the tires will help the other, less talked about source of pollution from cars. Thankfully, we have the ability to make it a reality with little to no noticeable difference to the end user.