Tyres

Safety first when it comes to tyres. We trust them with our lives. The law in the UK is clear. The tyre tread depth must be at least 1.6mm across the centre ¾ of the width and around the whole circumference.

There are many sites and automotive sites that recommend changing tyres when they approach 3mm tread depth. So is this good safety practice or a cynical ploy to get us to replace tyres before they really need to be replaced? The safety case comes down to worn tyre performance, especially in wet weather (dry weather stopping distances might actually improve with wear, just like the slicks used in motorsport on dry days). As consumers we really need to be able to understand what wear does to our tyres, and in particular how it changes our wet weather stopping distances. This consumer information would help us make informed choices on the level of wear we can accept for the type of tyre we have. Otherwise we could be scrapping tyres that have good performance and increasing unnecessary consumption of raw materials.

Tyres are not all the same. A premium tyre with fantastic wet weather performance when new may well have good wet weather performance when fully worn, whereas a cheap budget tyre may not be much better when new. As we are on average driving on part-worn tyres then the new wet weather performance might not be that relevant anyway! This reinforces the point that worn tyre performance would be useful consumer information. The rate of wear of tyres is different too. So maybe a tyre wear test to establish a comparable wear rate would be a welcome piece of consumer information. From 1 May 2021, the EU tyre label covers energy efficiency, wet weather performance (when new), noise and now snow and ice performance [1]. Wear or durability and worn performance is still not presented.

Truck and van tyres are heavily used and in the past the economics have made it easy to retread tyres to give them an extended life. Premium tyres designed to be retreaded may have their lives extended twice, tripling the distance covered and potentially achieving 660 thousand km per tyre [2]. The European retreading industry has provided jobs for this circular economy activity. Unfortunately when cheap poor quality imports arrive on the market that cannot be retreaded, the result is a reduction of jobs in retreading and an increase in consumption of raw materials. A report reviewing this little known part of the economy that has traditionally practised repair and reuse may be of interest [2].

The other thing about tyres is that this is a non-fuel purchase that will continue as people start to switch to electric vehicles. Added to that, as electric vehicles are generally heavier than their older internal combustion engine cousins, the level of tyre wear might actually increase slightly in future. Concerns on the tyre wear and brake wear dust in the vicinity of roads are now more likely to be talked about as tailpipe emissions are eliminated. Electric vehicles with regenerative braking may reduce brake wear substantially, but not tyre wear.

And then we come to the environmental concerns associated with tyres. Where does the rubber come from? How easily are they recycled? What happens to all that wear dust? An overview of these concerns coinciding with the increase in awareness of microplastics is discussed in the National Geographic [3]. A paper reviewing the lifecycle environmental impact of a passenger car tyre is [4].

There are three things we can do: consider tyre safety first (look after the tyres, their inflation pressures and so on); buy tyres that will last longer (this may mean buying more expensive premium tyres but less often); and moderate our driving style to reduce wear.

[1] Tyres, Energy Label, EU website, https://ec.europa.eu/info/energy-climate-change-environment/standards-tools-and-labels/products-labelling-rules-and-requirements/energy-label-and-ecodesign/energy-efficient-products/tyres_en, retrieved June 2021.

[2] The socio-economic impact of truck tyre retreading in Europe: The circular economy of tyres in danger, October 2016, EY, https://www.etrma.org/wp-content/uploads/2019/09/201611-ey_retreading_lr.pdf, retrieved June 2021.

[3] Root, T.; Tyres: The plastic polluter you never thought about. National Geographic website, https://www.nationalgeographic.co.uk/environment-and-conservation/2019/09/tyres-plastic-polluter-you-never-thought-about, retrieved June 2021.

[4] Piotrowska, K.; Kruszelnicka, W.; Bałdowska-Witos, P.; Kasner, R.; Rudnicki, J.; Tomporowski, A.; Flizikowski, J.; Opielak, M. Assessment of the Environmental Impact of a Car Tire throughout Its Lifecycle Using the LCA Method. Materials 2019, 12, 4177. https://doi.org/10.3390/ma12244177

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