One of the significant benefits of an EV is reduced mechanical component wear and maintenance. Unlike a car powered by a conventional petrol or diesel engine, an EV has no reciprocating engine parts. Or the need for fuel and air filtration or hoses to guide them. An EV is much cheaper to run from a maintenance perspective without moving parts or filters that wear and clog, requiring replacement.
Tyres are one aspect where EVs and conventionally powered vehicles are similar and owners only think of tyre costs and issues when it’s usually too late.
Data from UK breakdown service provider, Start Rescue, tallied 29% of its EV-related callouts for last year being related to flat tyres. Regarding the cost of ownership, tyres can be an unappreciated part of your calculation because EVs have specific characteristics that can make their tyres live quite a harsh life.
EV tyres are different
Tyres are wear items but are also a crucial safety and performance feature of any car. As the contact patch, tyres must manage a vehicle’s acceleration, braking and turning. Often, those inputs from the driver must be fulfilled by the tyres in challenging road conditions covered by rain runoff or snow.
Great tyres can make a car of average design feel more stable and agile, while poor tyres can make an excellently engineered vehicle platform feel compromised.
EVs and tyres have a peculiar relationship with each other. In conventional petrol or diesel cars, tyres are optimised for mechanical grip, which means they sacrifice some efficiency. The logic is simple: the grippier a tyre is, enhancing braking and cornering, the more rolling resistance it must have, creating greater drag and higher fuel consumption.
For EVs, efficiency is the highest principle of engineering. From aerodynamics to tyres, an EV design and engineering team want to optimise everything possible to increase range. And that means tyres with the lowest possible rolling resistance and less grip.
Most cars, especially those with a lot of power, roll tyres designed for the specific model. Car brands, their R&D teams and tyre companies work to produce tyres optimised for a vehicle’s specific weight, power, centre of gravity and safety systems. For EVs, there is the additional requirement of range, and that’s why a new generation of tyres is needed.
Instant torque and tyre wear
EVs are heavier for a given set of dimensions and feature more available powertrain torque than a similarly sized petrol or diesel vehicle. And that creates issues regarding tyre requirements and wear.
To optimise range, engineers choose tyres with the least drag for an EV but also need to consider the additional vehicle mass and powertrain torque delivery issues.
Where petrol- and diesel-powered cars need gears to manage the discrepancy between linear torque build-up and engine speed, EVs instantly deliver all their torque. And that means the tyres are exposed to a much higher load from pull away. With a powerful petrol or diesel vehicle, the driver can modulate torque deployment much better because it increases linearly with engine speed, which is not the case with an EV.
Because there’s so much more torque available, from the first moment those electric motors start rotating the wheels, it’s virtually impossible to drive an EV ‘gently’ from pull away to the legal road speed. This surplus of powertrain torque, flowing abundantly to the drive wheels from pull away, is creating some of the accelerated tyre wear some EV owners are experiencing.
Some EVs have throttle response settings, which drivers can select to make throttle response milder but it’s a marginal difference.
Weight and tyre pressure
An avalanche of instantaneous torque burdens EV tyres, increasing wear, but weight is an issue, too. As we’ve mentioned, EVs are heavy, which means more point loading on your tyres, increasing wear.
The weight loading of EV tyres is one of the reasons why pressure discipline is crucial. Tyres companies conduct exhaustive testing to find the ideal pressure range for a specific tyre type, size and its corresponding target vehicles. If you keep tyres correctly inflated, they will operate optimally, but when under or overinflated, tyre performance degrades – and wear can increase.
Considering the weight of EVs, it’s even more critical to ensure that your zero-emissions vehicle is always running at its correct tyre pressure. Checking and inflating tyres isn’t a chore and ensures your EV doesn’t suffer excessive tyre wear.
2WD or 4WD? It matters
Your EV’s drive configuration appears to significantly influence its tyre wear. Research by Continental, the German tyre, automotive component, and safety systems specialist, has shown that two-wheel drive EVs have the worst tyre wear. Whether front- or rear-wheel drive, EVs with a single-drive axle deliver tyre wear up to 25% more.
But what about all-wheel drive EVs? That’s where the Continental tyre wear research becomes interesting. With the instantaneous torque of an EV powertrain distributed among four wheels and their tyre contact patches, there’s less specific load per tyre. And that means less typical wear, too.
The most remarkable outcome of the Continental EV tyre research is that all-wheel drive configured vehicles conserve their tyres better. How much better? Owners of all-wheel drive EVs could see 10% greater tyre life.
Beyond the benefit of distributing wear across all four tyres, instead of concentrating torque-loaded wear onto only two, there’s another reason why you might be better served by an all-wheel drive EV – safety. When driving in wet or snowy conditions, all-wheel drive has far superior traction, especially considering the immense torque delivery of most EVs, making it the superior choice for driving in all conditions, year-round.