Tyre manufacturers are under pressure to almost literally reinvent the wheel as regulators focus on tyre pollution, which is expected to rise with the rise of electric vehicles (EVs) and threatens to undercut those vehicles’ green credentials.

Tiny particles are abraded and released when tyres make contact with the road. Because of the additional weight of EVs due to their batteries, this little-discussed source of pollution – from an estimated 2 billion tyres produced globally each year – is becoming a significant issue.

Major manufacturers such as Goodyear, Bridgestone, Michelin, and Continental are also battling cheaper Chinese competitors.

“It’s not quite a perfect storm,” said Gunnlaugur “G” Erlendsson, CEO of UK-based startup Enso, which has developed more durable tyres specifically for EVs and rents out tyres that it takes back to recycle at the end of life. “But it’s close.”

Tyre manufacturers are scrambling to develop alternatives to emissions regulations.

New research is demonstrating the toxicity of tyres, which contain an average of 200 components and compounds, many of which are generated from crude oil.

While detractors claim that tyres contain numerous hazardous and carcinogenic chemicals, there is currently only agreement on one – 6PPD, an antioxidant and antiozonant found in all tyres that decreases cracking.

California is set to be the first government to insist that tyre manufacturers demonstrate that they are looking for a replacement to 6PPD, a degraded form of which is harmful to some fish and has been identified in human urine in South China.

For the first time, the European Union’s impending Euro 7 emission laws will establish tyre criteria.

Complicating matters, manufacturers will need to design low-emission tyres for heavy EVs, which, according to Michelin and Goodyear, can wear out tyres up to 50% faster.

“The unintended consequence of electric cars is we’ll have more tyre pollution unless we have better tyres,” said Enso’s Erlendsson, whose tyres, in testing emit 35% less than premium EV tyres from major manufacturers.

He claims that this is due to their reliance on higher-quality, more expensive materials, which make them more durable.

Bridgestone and Goodyear declined to comment on the industry’s pollution issues.

However, Michelin, Continental, and Pirelli all told Reuters that they are looking into alternatives to 6PPD, with Michelin and Continental saying that collective industry action may be required to develop solutions.

When asked about Euro 7 restrictions, Michelin stated that it wants global standards to push higher emitting tyres, which are typically cheaper, out of the market. Continental supports a global abrasion standard with consumer-friendly labelling.

The “dirty end” of the list of tyres tested, according to Nick Molden, CEO of British-based testing business Emissions Analytics, are “cheap Chinese imports” widespread in the European market.

Rockblade, Mazzini, and Ovation, which are among the worst-performing tyre brands on Molden’s list, did not respond to calls for comment.

According to Emissions Analytics data provided to Reuters, new tyres created thus far are unlikely to remedy the problem.

While tests on Continental bicycle tyres made from dandelions reveal a 24.5% reduction in carcinogenic aromatics – which help cars hug the road – the compounds in the particles they emit are similarly harmful overall, according to Molden.

“They are just differently bad,” he added.

Continental stated that its dandelion tyres were created to find a sustainable kind of natural rubber, with 6PPD being a secondary goal.

“It’s our responsibility to take care of this and to find a solution” to 6PPD, said Thomas Kramer, Continental’s head of material wear.

Research demonstrates that when 6PPD combines with oxygen or ozone, it generates 6PPD-quinone, which has been implicated for huge fatalities of Coho salmon off the West Coast of the United States.

California authorities said the impact of 6PPD on human health is unknown, but they are finalising documentation that might oblige tyre producers to investigate safer options.

According to the tyre industry, finding a substitute for 6PPD is difficult because any new chemical must prevent tyres from degrading and cracking without impacting other properties.

“Tyres are a compromise” between safety, noise, handling and abrasion, said Adam McCarthy, secretary general of the European Tyre and Rubber Manufacturing Association.

Enso CEO Erlendsson stated that if pressed, the industry may have a solution on the market within five years, but at a cost.

Moving away from tailpipe emissions, EU and UN authorities are developing Euro 7 requirements to reduce emissions from brakes and tyres. According to EU MPs, they might be reached as early as next year.

According to research published for the European Commission, tyre particles are predicted to be the main source of microplastics potentially detrimental to aquatic life by 2050.

According to Michelin’s technical and scientific communications director Cyrille Roget, tyres emit roughly 3 million tonnes of particles each year and create another 3 million tonnes of particles from road surfaces.

According to Michelin’s tests, if you drive 200,000 kilometres (124,274 miles) a year on its tyres, you’ll produce about 1.5 kg (3.3 lb) of particles, compared to a market average of 3.6 kg.

Michelin has evaluated the worst-performing competition tyres so far, and they emit roughly 8 kg per year.

If Euro 7 were used to prohibit the sale of the most polluting tyres, “you would already remove a lot of particles from the market,” according to Roget. “That’s the first step, and it’s something we believe can be done more quickly.”

Michelin and Continental both stated that they are already working to make their tyres more durable; Michelin, for example, lowered its tyre emissions by 5% between 2015 and 2020, according to Roget.

However, Emissions Analytics’ Molden believes that the change to EVs will compel tyre manufacturers to build more durable tyres – a daunting issue without natural rubber, which would be difficult to develop sustainably enough to support the entire industry.

Enso has a recycling agreement with the Norwegian company Wastefront as part of their efforts to be as environmentally friendly as possible.

“The advent of the EV is the time to make this change,” to improve tyres,” Enso’s Erlendsson said. “We’re never going to end up having zero tyre pollution, but we can reduce it.”

(Adapted from Reuters.com)