Vulcanised Technology: Ride Long and Prosper – Movin’On 2021 (Part 1)

There are many more electric cars on the streets and motorways. Notwithstanding their much cleaner propulsion, there is another key difference – electric cars weigh about 1,000 pounds/454 kg more than comparable internal combustion engine (ICE) equivalents. That impacts the tyres, and henceforth tyre design.

Furthermore, electric vehicles (EV) still lack the range of their internal combustion engine (ICE) cousins. Thus much research and development is going into optimising EVs’ efficiency, and therefore range. One aspect hitherto that has not much attracted much research and development to date is their tyres. Reduced road-tyre friction means longer EV range. But it’s not that simple.

Despite what you might think (if you indeed ever thought about it), tyres are often tailored to individual vehicle makes, and even models, due to the interaction of the weight, the torque, and the chassis of the vehicle.  This is particularly important for EVs, for which range is the highest concern of manufacturers and drivers.

Not content with just range improvements, Michelin has already started equipping many of its tyre lines with sensors and transmitters to monitor wear.  As well, the French conglomerate is working to make tyres fully recyclable.

Movin’On Summit

This is the third instalment of reporting on the Movin’On Summit, the annual conference which covers all forms of mobility. This Summit generally leaves railway and bus topics to those industries, but does cover related transport issues, including energy efficiency, digital optimisation, and artificial intelligence, amongst others. As for most events, 2020 was a bye year, but this 2021 event was virtual.

Herein we return to a topic covered at the 2019 Summit, non-inflatable tyres. But this year, the Summit looked at a different approach how to make inflatable tyres more environmentally friendly and durable.

Tyre advances could be even more significant for electric buses and trucks, as EV car improvements have generally scaled up well to larger vehicles so far. Given the number of 18 wheelers on the world’s highways and roads, tyre improvements would provide significant fuel savings and extend EV range.

Design trade-offs

Designing tires for an electric vehicle involves the subtle art of tradeoffs. Minimising rolling resistance directly reduces energy consumption. But too much tyre stickiness to the road and the EV won’t travel as far on a charge. Too little stickiness and the vehicle can dangerously slide off the road. The majority of road noise comes from tyres sticking and unsticking themselves from the road. That sound is not going away.

How is an electric vehicle tyre different?

As ICE cars and SUVs overall average nearly 4,200 pounds/1,905 kg, a 1,000 pound/454 kg battery raises vehicle weight almost 25%. So the materials used have to be increasingly lighter, to counteract this. But the tyres also need to be even stronger to handle the additional weight, whilst still being robust over years of harsh weather, road conditions, and often drastic driving styles.  Such are the engineering tradeoffs.

In March 2021, Michelin unveiled its e.PRIMACY tyre for electric SUVs which will increase range up to 7%. Its high-tech tyre composition reduces road resistance whilst maintaining the performance. The company also developed the Pilot Sport tyre for electric sports cars, which adds up to 37 miles of additional range. However, no company is giving any hints as to the composition of their new high-tech tyres.

Not the same tyred approach

Michelin is not the only company looking to reducing rolling resistance. UK tyre startup ENSO has developed a tyre designed to increase electric vehicle range by up to 11%, and to shed less particulate matter (PM) pollution than normal tyres.

At least one study has found that air particulate pollution from car tyres can be up to 1,000 times worse than from engine exhausts. Medical researchers estimate that PM pollution costs the average person 2.2 years off their life. Unfortunately, tyre pollution is an even bigger problem for EVs than ICE cars, as the formers’ increased weight and torque wears down tyres faster, emitting more particulates.

To address this, ENSO’s is developing tyres made from environmentally friendly raw materials, and utilising innovative compound development techniques. The goal is to greatly reduce the quantity and toxicity of harmful particulate emissions that tyres release, reducing both air and microplastic tyre PM pollution. Preliminary testing started with ENSO’s partnering with logistics and delivery company DPD to conduct full road trials with their electric vans.

This was promising, and ENSO was also one of the winners of TfL’s London FreightLab Innovation Challenge, which is enabling testing of new tyres shortly. A collaboration with Royal Mail will trial the tyres on 15 of electric delivery vans at their West London Delivery Office near Wembley, in a six- to nine-month trial.

Not to be outdone, Michelin has been working on its own sustainable tyre recipe since 2017. This is part of its goal to strive for 100% of its tyre materials being sustainable by 2050. With the interim target of achieving 40% sustainable materials by 2030. The company unveiled a tyre on that evolution at Movin’On 2021, unveiling a tyre demonstrating concrete technological advances in the integration of sustainable materials. These advances were stress tested in Michelin’s motorsports participation. 

One example of Michelin’s work is to produce butadiene, a key component in the synthetic rubbers used to make tires, from biomass (waste wood, rice husks, corn stover, etc.) instead of from petroleum. This is just one of over 200 materials used to fabricate its tyres, including natural rubber, synthetic rubber, metal, textiles, reinforcing agents (carbon black, silica) and resins, as well as sulfur for vulcanisation.

Billions and billions

There are 1.4 billion cars and trucks currently on the world’s roads, and an estimated 2 billion by 2035 (not including motorbikes, auto-rickshaws, or other non-standard vehicles). Multiply these numbers by four tyres per vehicle (as these are the predominant type) means over 5.6 billion tyres on the road now, all spewing particulates.

So tyres are an excellent, and a hitherto too long overlooked, component to improve upon.

In the second part of the MovinOn 2021 Summit report, we will look at global shipping sustainability advancements.

Thanks to the Movin’On Summit for providing access to the virtual proceedings.