Michelin – All our tyres are EV-suitable

Although the Society of Motor Manufacturers and Traders (SMMT) indicates that battery electrics will hold a 17.8 per cent new car market share by the end of 2023, vehicles powered from the socket remain the subject of lively debate and sensational headlines. Tyres aren’t exempt from such discourse, as the Daily Mail made clear in July when maligning these as the “dirty secret behind your electric vehicles.” To bring some common sense back into the EV tyre conversation, Michelin has shared its views on the subject.

It’s no dirty, tabloid secret – the additional weight of batteries and greater torque mean that tyres fitted to electric cars typically wear comparatively faster. Marika Hoflund shared a few figures with us at an event in Sweden, a country where plug-in EV market share exceeds 60 per cent. According to the Michelin Nordic managing director, compared with ICE vehicles, tyre treads wear up to 20 per cent faster when fitted to EVs.

“Tyres with a lifespan of 50,000 kilometres on a combustion engine car will roll 12,000 kilometres less when used on an electric car before wearing to the legal limit of 1.6 millimetres tread depth on summer tyres.” Hoflund considers this a “very significant difference” but is quick to point out that not all tyres are created equal. She adds that Michelin has worked hard to find solutions to this and other challenges.

The solution we’re seeing across the industry is EV-suitable tyres, and here Hoflund has some good news. “All Michelin tyres are suitable for electric vehicles thanks to their intrinsic qualities such as rolling resistance, wear, noise, abrasion and grip. These are qualities not only relevant to EVs, but to all cars.”

Marika Hoflund, MD of Michelin Nordic (Photo: Tyrepress / Stephen Goodchild)

Hoflund comments that “a good rule of thumb is that there is a correlation between price and quality,” which is one way of describing the premium pricing of Michelin products. The managing director adds that “EV-suitable tyres will come at an added cost for consumers” but stresses that tyre buyers need to look at whole-life cost rather than just initial purchase price. She also warns that equipping EVs with “average ICE tyres” will be “more expensive in the long run” due to their faster wear and the effect this has on rolling resistance. Equally important for Hoflund and Michelin is the “very heavy” impact of standard tyres upon our planet through wear-related particle emissions.

A big difference

With microplastic emissions from tyres an issue that’ll be addressed by upcoming Euro 7 standards, Michelin’s interest in this area is more than piqued. Hoflund’s colleague Richard Andermyr confirms the tyre maker’s support of set thresholds for tyre particle emissions. Andermyr, sustainability manager for Michelin in Sweden, points to a “big difference” between the best and worst performers in this area.

Using figures gleaned from Dekra testing of more than 2,000 tyres between 2013 and 2018 as well as results extrapolated from Auto Bild all-season tyre testing, Michelin estimates that a set of four CrossClimate 2 tyres driven for 20,000 kilometres (12,427 miles) will release 1.5 kilograms of particles into the environment. Andermyr shares that the “market average” particle emissions over 20,000 kilometres is 3.5 kilograms while the worst-performing tyres release 8 kilograms of particles.

“There is a big difference, and it can have a huge impact,” he comments. Solutions to the problem of tyre abrasion focus on materials and construction, and these have resulted in Michelin reducing its tyres’ particle emissions by some five per cent since 2015. And when German motoring association ADAC recently examined almost 100 summer and winter tyres in a range of popular sizes and patterns, it found that average abrasion and thus particle emissions would decrease by 28 per cent if all vehicles ran on Michelin tyres.

Driving to the last millimetre

In addition to minimising wear and particle emissions through tyre construction and materials, Michelin champions another practice – one that also reduces average rolling resistance.

Michelin began focusing on rolling resistance more than three decades ago and brought its first optimised tyre to market in 1992. The Michelin Energy achieved rolling resistance of approximately 12 kg/T, which was very low for the time. Rolling resistance for current products such as the Michelin e.Primacy and Pilot Sport EV is just half this. Andermyr says the tyre maker “wants to go further” with optimisation measures and aims to decrease rolling resistance by a further ten per cent between 2020 and 2030. Tyre construction and materials will continue to play a role here, but so will Long Lasting Performance.

We’ve covered Michelin’s Long Lasting Performance campaign on various occasions over the years. At the heart of the campaign is a commitment to develop tyres that offer safe driving performance right up until the legal tread depth limit of 1.6mm. Michelin is arguably the strongest supporter of 1.6mm tyre changes, with some manufacturers and tyre associations recommending the replacement of tyres at a much more conservative 3mm or even 4mm tread depth.

The lower the tread depth, the more slowly a tyre wears and emits microplastics, as there is less movement in the tread blocks and less heat build-up. The final 1.4mm of tread before the legal limit may account for a fifth of the tyre’s lifespan. And as Andermyr explains, replacing tyres at 1.6mm also substantially reduces average rolling resistance.

Before Michelin considers a tyre sustainable, it must maintain key performances, including safety at a low tread depth (Photo: Tyrepress / Stephen Goodchild)

Tyre use & rolling resistance

Using a table comparing the wear characteristics of two tyres, one that is removed from service with 3mm of tread remaining and one that continues in use until reaching 1.6mm, Andermyr explains that although rolling resistance declines in tandem with tread depth throughout the entire life of the tyre, the biggest drop in rolling resistance occurs during the final millimetre or so before 1.6mm. “As the tread depth is lower there is less movement in the tread, which results in less rolling resistance.”

Whereas the tyre used until 1.6mm (we’ll call this Tyre A) continues in service and encounters less and less rolling resistance, the other tyre (Tyre B) is removed at 3mm and replaced by a new tyre. This substitute Tyre B brings with it a new, unworn tread whose blocks move more and result in higher rolling resistance. “All this energy that is saved with Tyre A is lost to Tyre B, reducing battery range,” says Andermyr. Michelin calculates that a fleet of 50 vans (each weighing up to 5 tonnes) could save 1,000 litres of fuel by demounting tyres at 2mm instead of 4mm, an amount equal to 9,800 kWh.

Source: Michelin

“A huge amount of energy is lost by not using tyres all the way down, and that is why we are working so hard on lasting performance so that our tyres become better when they are worn and are safe when they’re worn,” Andermyr adds. “This is extremely important.”

Blazing a trail

Andermyr concludes by summarising the Michelin solution to the weight, wear and range challenges posed by electric vehicles. “We want to create tyres that reduce their environmental footprint. We want the tyre to maintain key performances, including safety at a low tread depth, and we need to mass produce those tyres. Only then can we call them sustainable.”

Several tyre makers have adopted sidewall logos to denote their tyres’ EV compatibility and we’d be thrilled to see a jaunty design such as, say, Bibendum the Michelin Man sticking his finger into a power socket. But Michelin has, so far at least, resisted the urge to mark its tyres as EV-ready. As Marika Hoflund already pointed out, all Michelin tyres are suitable for fitment on electric vehicles.

No special logo – the entire range is EV-suitable (Photo: Tyrepress / Stephen Goodchild)

“With the help of tougher yet flexible rubber compounds in combination with other new materials in the tyre, we’re striving to counteract the extra wear and tear on electric cars,” Hoflund continues. “As of late, many other tyre manufacturers have started on the same journey as us, introducing different versions of tyres for hybrid and electric cars that promise to reduce rolling resistance and to give more kilometres on a charge. This trend shows that we’ve been on the right path all along with our tyre development, and I’d say we’ve blazed a trail for the tyre market in this regard.”

Still looking youthful & charged up despite his 125 years – Bibendum, the Michelin Man (Photo: Tyrepress / Stephen Goodchild)