Eco-friendly tires are something of a holy grail in the car industry, as these essential wear items have long suffered from confoundingly problematic production, emissions and disposal issues. At this week's IAA Munich Motor Show,debuted its Conti GreenConcept, a retread-ready smart tire made from renewable, recycled and traceable materials designed to combat exactly these problems. Packed with future tech that belies its ordinary appearance, the Conti GreenConcept offers a look at what could be rolling beneath your car in anywhere from 8 to 10 years -- and bits and pieces of this tire's underlying construction and tech will likely find its way into production far sooner.
Comprised of 35% renewable and 17% recycled materials, the GreenConcept does away with most conventional silicates (traditionally made from sand heated to 2,500 degrees Fahrenheit) in favor of silicates derived from the ashes of rice husks -- normally a waste product in the grain's production. The tire also includes natural rubber produced from the roots of dandelions, a technology Continental has been researching since 2011. Further, the sidewalls employ polyester strands derived from recycled plastic bottles -- each tire uses about 15 bottles' worth of materials. Finally, the GreenConcept also greatly curbs the usage of crude-oil-based resins and oils, substituting vegetable-based plasticizers instead.
These new materials have the side benefit of creating a substantially lighter tire; the GreenConcept tire weighs around 16.5 pounds, roughly 40% less than an equivalent normal rubber tire. This should not only improve a vehicle's ride and handling by reducing unsprung weight, this tire is also claimed to have 25% less rolling resistance than many of the best-performing tires today (those with an EU Class A rolling-resistance rating). Continental claims that this translates to up to 6% better range on EVs -- frankly, a massive improvement in an industry that sweats over single-percent increases.
The likelihood of a production model being that light depends heavily on the tire's usage case. As Continental's CEO, Nikolai Setzer, told me in a media roundtable in Munich, "This [the GreenConcept] is obviously a very lightweight construction. You have to look into 'where I can use it' and 'how can I use it?' Is [the tire] stiff and stable enough to be used on Michigan roads, for instance, after winter? Or do you combine it with a sensor assembly [telling you] where the potholes are so that you don't risk a flat tire? So you have to balance [weight] with performance, and then you might reduce a little bit from the weight to ensure [performance]."
That said, this isn't all pie-in-the-sky technology. Continental will begin rolling out tires produced with its so-called ContiReTex technology -- including reclaimed steel and recovered carbon black, as well as reclaimed PET bottles -- in 2022.
Are retreads the future?
One of the more interesting possibilities that the GreenConcept brings up is the idea of retreads -- reusing the base tire casing and refurbishing the wear surface to reduce material usage and lower costs. For the purposes of this concept tire, Continental built the GreenConcept with an inner green layer to indicate the replaceable portion of the tire. A sensor inside the carcass monitors tire health, including pressure, temperature and tread depth, meaning it's capable of telling owners when it's time to add air or even consider a retread.
Today, retreads are commonly found on heavy-duty commercial truck tires. Rightly or wrongly, however, when it comes to traditional passenger-car tires, retreads have historically been the subject of considerable suspicion, with consumers viewing the refurbishment process as inferior and potentially less safe than all-new tires. The GreenConcept aims to change that perception with better performance and reduced resource consumption.
It's important to note that Continental isn't necessarily signaling that it sees passenger-car tires moving to retreads, but it is investigating the idea, using the GreenConcept to test public opinion on the matter. According to Setzer, "We are not saying that ultimately this will come, but it is an option. It's clearly in the concept [that] we show it's possible, [but] whether the market is really coming up for this, with all the difficulties of distribution ... [including] how you refit [the treads], how do you do this in the [tire] store. That is [possible] on the B2B on the trucks. That's why it's still so strong over there."
As Setzer noted, the repair and service infrastructure that's in place to support the trucking industry favors retreads more than traditional passenger cars. But it's also the differing construction of commercial truck tires themselves that make retreads viable. "Maybe [it's] because trucks' [tires] have steel carcasses, a much stronger underneath casing where you can renew [them] ... [passenger] cars have textile carcasses where typically, the underneath is, after retreading, is not that strong enough that you still have the same integrity in terms of rolling resistance and the same performance."
Continental's wider goal is for all of its plants to produce zero carbon emissions globally by 2040, and by 2050, the company aims to have a completely carbon-neutral supply chain. It's here where the increased traceability of the company's raw materials become important. It's also where not having to source rubber from tropical parts of the globe (versus dandelions, which grow just about everywhere) could pay big dividends. That's not just true for curbing emissions generated by the material's harvesting and shipping, but also in terms of reducing potential environmental concerns like deforestation -- not to mention tackling the related human rights violations that dog today's rubber trade.
Plenty of challenges lay ahead on the road to volume production, but compared to more recent fantastical future-tire ideas like, commercializing at least parts of Continental's revolutionary GreenConcept tire seems downright reasonable. What's more, the potential upsides for the manufacturer, consumers and mankind alike all seem far too big to ignore.