Electric cars are typically 23% heavier than equivalent gasoline cars because of their battery. For the moment, it is estimated that this additional weight is associated with 15% faster tire wear, reports Denis Rodrigue, professor at the Faculty of Science and Engineering, whose laboratory is working on the recycling and the revaluation of tires.
To better understand the phenomenon and the factors that influence this difference, further studies are underway. They consider the type of driving, i.e. acceleration, braking, in the city or on the highway, the type of tires (winter, summer, all-season), the manufacturer and the weather conditions, such as temperaturerain or snow. There power of these vehicles is also a factor of wear, as the tires experience more friction when starting. “For a gasoline car, let’s say we should be able to do 100,000 kilometers on the tires. With a electric vehiclewe are only going to make 85,000, or 15,000 less, illustrates the professor. This is significant considering that this represents what motorists travel in average par year. So we’re doing the equivalent of one year less with tires.”
To overcome this problem, with a view to a shift towards electric vehicles, cars would need to be made lighter or tires more durable, in particular by changing their size. “We must keep in mind that the larger the tires, the more difficult they are to manufacture, handle and change. With the congestion in garages for changing tires, this is an important factor,” underlines Professor Rodrigue .
In Quebec, a car must be fitted with winter tires before December 1. Denis Rodrigue reminds us that we cannot bring forward our appointment at the garage to unclog it, because the tires have an optimal temperature range. “Summer tires have harder rubber and winter tires have softer rubber. A hasty change can lead to premature wear,” explains Denis Rodrigue.
The challenges of recycling
To make tires more durable, their composition can be modified, but this makes recycling more complex. “Each company has its own secret recipe, with varying products and concentrations. When we collect the tires, all the brands go to the same place, it’s all shredded ensemble. It’s the same thing for summer and winter tires,” underlines Professor Rodrigue.
In his laboratory, when he receives a new set of tires, his team analyzes them to get a rough idea of the compositions. This makes it possible to determine how to treat them, particularly when choosing the temperature. According to Professor Rodrigue, variations in composition become especially a problem for retreading, which consists of replacing the worn tread of a tire with a new one. “If you want good grip between the new tread and the old one, you have to know the composition of the tire.” The simplest recycling method currently is reuse. “Tires are often cut and then reused into pieces. For example, the outer part of the tire can be used as a support for orange cones, stacking two or three pieces to add weight to the base.”
The tread can be used for stable or arena carpets. A company makes dumbbells out of them. Rubber particles are sometimes embedded in asphalt or concrete.
The number of tires that are collected increases every year. This trend is therefore on the rise. According to Denis Rodrigue, this currently poses a problem, because there are not enough companies in Quebec to locally recycle all the available quantities, and especially to recycle entire tires that contain metal, fibers textiles and rubber. We must therefore find better outlets to create added value instead of burning or burying the material.
