Electric vehicles and varying tyre dimensions – these topics were thoroughly checked by the Swiss technical journal “auto-illustrierte”. Different tyres in sizes of 18 and 19 inches were tested. The test subjects included the Goodyear Eagle F1 Asymmetric 6 in 18 and 19 inches, the 19-inch budget tyre Matador MP 47 Hectorra 3 from Continental, and the Goodyear EfficientGrip Performance 2 in 17 inches. The neutral experts from TÜV Süd (a technical inspection authority) accompanied the tests.
“The tyre market has demonstrated that electric vehicles can be considered as norm”, says Michael Stamm, tyre expert at TÜV Süd. He adds: “There are hardly ever tyres that are used for electric vehicles only. Electric drivers would like to have access to the whole range of products when buying tyres.” This is also caused by the big variety of available vehicles and the different driving profiles. Whoever has to cover long distances with an electric vehicle or would like to go faster every now and then, appreciates a sporty style when using an electric car too. The market has been adapting: “Thus, running smoothness, stability and less rolling resistance can be found in each product specification when developing new tyres. Tyres with smaller dimensions are, however, useful for urban use in order to protect the environment and the purse.“
Different test requirements
During the tests on hot summer days in Mireval, the editors of auto-illustrierte mounted different tyre dimensions and brands to a BMW i4. The following variations were tested: the BMW had a mix of the Goodyear Eagle F1 Asymmetric 6 245/40 R19 on the front axle and the Matador MP 47 Hectorra 3 in 255/40 R19 on the back axle. Another tyre combination in 18 inches consisted of the Goodyear Eagle F1 Asymmetric 6 and the sizes 245/45 R18 on the front axle as well as 255/45 R18 on the back axle. The Goodyear EfficientGrip Performance 2 in 225/55 R17 was mounted all around the car as basic tyre equipment.
Wet braking
When braking on wet roads with 80 kilometres per hours, the Matador shows considerable weaknesses. It is able to stop the test vehicle only after 41.1 metres. For a comparison: the 18-inch tyre from Goodyear needs 31.4 metres and the 19-inch one from Goodyear 31.5 metres. When comparing, the car with 18-inch tyres from Goodyear is already standing while the vehicle with Matador tyres is still moving at a speed of 38.6 km/h.
Dry braking
Concerning dry braking, the Goodyear Eagle F1 Asymmetric 6 (18/19 inches) turns out to be the best. From one hundred to zero, they offer 32.4 and 33 metres to stand still. The Matador needs 35.2 metres, whereas the BMW speedometre gets to zero after 35.5 metres with 17-inch tyres. You can find a similar picture when looking at wet circle tracks – here the two big tyres from Goodyear are in the lead. They finish the 42-m-long round at an average speed of 66.9 km/h (18 inches) and 67.4 km/h (19 inches). The 17-inch tyres and the Matador move much slower in the circle. 64.7 and 64 kilometres per hour respectively.
There is a completely different picture with regard to aquaplaning in about 8mm of deep water. Here the smaller 17-inch tyres and the tyre from Bratislava (Matador) show the best results. The smaller one floats at a speed of 84.5 km/h and the 18-inch low budget tyre from Continental at 83.9 respectively.
In all the further tests, the Matador representative keeps its last position. In the disciplines of dry and wet handling, it is considerably slower on the move and shows less performance in the area of stability in a very noticeable way. And unfortunately, the alternative tyre with the most reasonable price is not really able to convince in the test lab of TÜV Süd either. When looking at the most important criterion of rolling resistance – an indicator for low energy consumption – it finds itself in the last position too. At the same time, a higher rolling resistance certainly costs some kilometres with regard to mileage too.
No compromises
Stamm, the TÜV Süd tyre expert, comes to the following conclusion: “Whoever needs new tyres for an electric car should pay special attention to rolling resistance and running smoothness in addition to general safety parametres“ Moreover, there is always the possibility to buy again the tyres mounted to the vehicle by the manufacturer as first equipment. Usually, it is optimized for the model. “It would have been exciting to have tested a tyre used as original equipment too”, adds Stamm.
The test result has shown as well that compromises should be avoided when buying new tyres for an electric vehicle. According to Stamm, using alternative products at an extremely reasonable price – for electric or other vehicles – could have a huge impact on safety.
