Michelin calls for worn tyre testing

If Michelin is right then the world could be about to change the way it looks at tyres.

It wants buyers to use braking performance with worn tyres on a wet road — not dry-road grip on a new tyre — as their primary consideration for rubber choice.

It’s also keen to see real-world testing of tyres, in a similar style to NCAP crash tests and Europe’s new WLPT fuel consumption tests, to give consumers a better chance of choosing the safest rubber for their vehicles.

“The problem is that all testing is now done with new tyres. We need testing with worn tyres,” says Cyrille Roget of Michelin.

“The only time a tyre is new is when it is on the shelf. After that it is always worn to some degree.”

Not surprisingly, Michelin has a vested interest in a new scoring system and Roget, the company’s worldwide director of scientific and innovation communication, is pushing the message.

It is about to launch its new Primacy 4 tyre in Australia after extensive research and development that’s reflected in the slogan ‘Safe when new, safe when worn’.

It’s a point Michelin proves during a press preview in Thailand, where the Primacy 4 comprehensively outscores rivals from Dunlop and Bridgestone during wet-weather braking exercises, which are the toughest challenge for any heavily-worn tyres.

In an 80km/h panic stop on a soaked road a heavily-worn Michelin even outscores brand-new tyres from one of its rivals.

But there is no real chance to test the other claims for the Primacy 4, which include more comfort and less road noise.

We do get a chance to speed around a motorkhana in a Mercedes-Benz wearing the Primacy 4, and about 5km in a Toyota Camry — including a 200-metre ‘comfort test’ — but there is zero chance for a realistic assessment of the tyre.

Michelin is not revealing pricing or exact sizing for the Primacy 4 until it hits tyre dealerships next month, but local spokesman Angus Thompson promises “no significant change” from the existing Primacy 3, which is likely to mean around $130 for a 205x55 R16.

The Primary 4 is a mid-level tyre in the Michelin range — not nearly as grippy as its headliner Pilot Cup Sport 2, but intended for regular family cars and offering mileage in the 40,000-50,000km range.

But it has a stronger focus on safety and particularly wet braking, which Michelin research shows is a significant worry for owners who — it says — can feel the difference well before the tyre is worn down to the legal limit.

“A lot of people have anxiety about the safety of used tyres. As soon as you start to drive the tyre performance changes. A little bit at the start, then faster and faster,” says Roget.

But there are a couple of advantages to worn tyres.

“When worn, grip will improve on a dry road. This is like a racing tyre.

“When worn, the fuel consumption also improves. One tank of five is consumed by the tyres because they are generating heat. There is less heat in a worn tyre from the tread.”

Michelin spends more than $1 billion a year in research and development by around 6000 technical experts. It 11,700 active patents and filed for 416 in 2017 alone.

It says its ‘innovation’ program now covers everything from replacing oil in tyres with wood and futuristic 3D-printing of tyre treads to cut environmental impact and improve safety.

“We need to think about the future. Tyres should be designed to perform well throughout the useful life,” says Roget.

Improving worn-tyre performance, so that people can get closer to the 1.6mm safety level than the 3mm level where most people currently replace their tyres, could save 35 million tonnes of CO2 a year, says Michelin.

“That’s enough to run New York City for six months. It’s a big city,” says Roget.

The research that resulted in the Primacy 4 included everything from better silica bonding in the rubber to an improved tread design, which protects the piping and grooves that remove water, as well as slightly better wear and quietness.

It talks about ‘Evergrip’ technology that boosts the pumping of water by 50 per cent when worn, compared to a worn Primacy 3.

Testing was originally focussed on Europe but now includes China and Thailand, using cars including the Camry and Honda Accord, including comparative testing with other Tier 1 and Tier 2 brands — which Michelin does not confirm officially but include Bridgestone, Dunlop, Hankook and Goodyear.

Michelin is chasing original-equipment contracts for the Primacy 4 but is currently focussed on the aftermarket with plans to sell the tyre in more than 170 countries with an extensive advertising program that focusses both on the tyre’s wet strengths and the concerns of ordinary drivers.

“Michelin starts a discussion around the worn-tyre performance. We think it is important, as an industry,” says Roget.