Tyres on an EV: why they wear faster

A tyre wears because the tread slips a little across the road surface with every revolution. How much depends on the forces passing through the contact patch: the load resting on it, the force with which it drives or brakes, and the force with which it holds the car in a bend. On an electric car the first two are usually larger than on a comparable combustion car, and they act more often.

Three traits are responsible. The battery makes the car heavier. The electric motor delivers full torque from standstill, with no clutch or torque converter to soften it. And regeneration brakes through the driven axle only. On a combustion car the braking system spreads deceleration across all four wheels, biased to the front; on a rear-wheel-drive electric car the rear axle carries both the drive and a large share of everyday deceleration.

How much faster a tyre wears on an electric car cannot be put into one figure. Driving style matters more than the drivetrain: drive smoothly and use regeneration gently, and a set of tyres lasts about as long as on a combustion car of the same class. Use the acceleration at every traffic light and you watch the tread disappear. Understanding the mechanics helps with both: buying the right tyre and spotting when something is wrong.

An electric car is often considerably heavier than a combustion car of the same size, because the battery weighs several hundred kilograms. More load means more flexing in the sidewall, more heat in the tyre and a contact patch that scrubs harder in corners. That is one reason for the wear, and one reason why load capacity is not a detail when buying tyres.

Load capacity appears on the sidewall as an index after the size, directly before the speed symbol. It is a table value: each number stands for a maximum load per tyre at a defined pressure. The minimum index your car requires is in the registration documents or the certificate of conformity. A tyre below it is not permitted, even if the size fits.

Two additions are common on electric cars. XL, for Extra Load, marks a reinforced tyre that carries more than the standard version of the same size at a higher pressure. HL, for High Load, is a newer level above that, created for heavy vehicles; the marking sits in front of the size designation. If a car left the factory on HL tyres, the replacements must be HL again. An XL tyre of the same size carries less.

On a used car it pays to look at what is fitted. A cheap set that matches the size but not the index is a defect you can see at the viewing, not only at the next inspection.

An electric motor delivers its torque instantly. Traction control stops the wheel from visibly spinning, but it allows slip below that threshold, and that slip is what rubs rubber away. Hard launches from standstill, repeated at every light, are the biggest wear factor on an electric car that you control yourself.

Regeneration works in the other direction. In one-pedal driving the car slows through the driven axle every time you lift off, often more firmly than you would coast in a combustion car. That spares the brakes, but not the tyres on the driven axle. A gentler regeneration setting lets the car roll more and reduces the load; if you drive with anticipation, you still rarely need the friction brakes more often.

It follows that the axles wear at different rates. With rear-wheel drive it is usually the rear, with front-wheel drive the front, and with all-wheel drive it depends on the split the software chooses. Where front and rear run the same size, swapping wheels between axles evens out the wear; whether and how often is in the owner's manual. With different sizes front and rear, as some models have from the factory, that is not possible, and the tyres on the driven axle simply get bought more often.

Rolling resistance arises because the tyre deforms with every revolution and part of that work is lost as heat. It grows with weight: the rolling resistance coefficient times the weight force gives the force that must be overcome all the time. On a heavy electric car that item is therefore larger, and because the drivetrain is otherwise very efficient, it weighs more heavily.

At low speed rolling resistance makes up a large part of consumption; on the motorway aerodynamic drag dominates. If you drive mostly in town and on country roads, you will notice the choice of tyre more clearly than someone who is usually fast on the motorway. As an order of magnitude, switching between an efficient and a thirsty tyre of the same size can change consumption by a few per cent, enough to see on the trip computer over a week.

In the EU the tyre label tells you. It rates rolling resistance in classes from A to E, wet grip likewise, and states rolling noise in decibels. The classes are comparable because they are measured by a common procedure. One trade-off remains: a compound tuned for very low rolling resistance may grip less well in the wet. The label shows both side by side, and for everyday use it is worth sacrificing neither entirely.

Besides the tyre itself, three things play a part:

Without engine noise you hear what used to be drowned out: rolling noise and above all a drone that builds up in the air inside the tyre and travels through wheel and axle into the cabin. Many manufacturers therefore fit electric cars with tyres that have a layer of foam bonded inside the tread. It damps that resonance. It changes little on the label, because the label measures noise outside the car, not in the cabin.

Each tyre maker has its own name for this version on the sidewall, often with words like “Silent”, “Acoustic” or “Sound”. On top come manufacturer markings showing that a tyre was developed for a particular car, such as a star for BMW, “MO” for Mercedes-Benz or a “T” with a digit, such as “T0”, for Tesla. Such a marking is not mandatory, but it tells you which tyre the car was developed on. A different tyre can be permitted and still sound and roll differently.

The foam matters when you get a puncture. Not every sealant from a repair kit is compatible with it; the maker of the tyre or the kit says which is approved. A permanent repair takes more work because the foam has to be removed at that spot, and not every workshop will do it. Since many electric cars come without a spare wheel, it is best to check beforehand what is on board for a flat.

Measure tread depth at several points across the width, not only in the middle. The main grooves contain small bars, the wear indicators; once they are flush with the tread, the tyre is finished. The legal minimum depth is set by each country and published by its road traffic authority. For wet roads and winter, the legal limit is not a good yardstick.

On an electric car it is worth comparing the axles and the inner and outer edges. The most common patterns:

Besides depth, age counts; how to read it from the DOT code and why a tyre with plenty of tread can still be finished is covered in the piece on tyre age. On a used car, four tyres of the same type with similar depth say more than any assurance. On Carvexia a seller can state when the tyres were last replaced. That appears as the seller's statement, not checked, and does not replace a look at sidewall and tread.

When new tyres are due, take the size, load index, speed symbol and additions such as XL, HL or the manufacturer marking from the old tyre or the registration documents. In the parts catalogue, tyres are listed under wheels and tyres. If the right version is not there, you can post a parts request that dealers carrying parts for your make can see; whether one of them sends an offer is up to them.