Conti rolls out e-car tyre

TO CATER to the 2.8 million electric cars expected by 2020, representing a market share of 3%, German tyre maker Continental has introduced Conti. eContact for e-cars and hybrid cars. A requirement was to reduce the rolling resistance by 30% to increase the travel range of e-cars and to facilitate longer operation with the
electric motor in hybrid vehicles.

To maintain high standards for directional stability and handling, different tread variants are produced in some
cases, also for use on the front and rear axle.

The tyre sizes also differ depending on the type of vehicle. For example, smaller, narrower dimensions are required for light urban vehicles, while e-cars with more volume use tyres for the 20 in. rims.

Continental engineers achieved the reduction in rolling resistance by using a large and narrow tyre dimension.
Thus, deformation of the tyre is reduced when entering the contact patch, lowering rolling resistance
considerably. This also means that the same load bearing capacity can be achieved as for conventional tyres.

In addition, the side wall of the tyre was designed in such a way that less energy is lost when the tyre
deflects and rebounds and the tyre weight was further reduced. These measures also lower the rolling resistance.

With its combination of four longitudinal grooves, high number of sipes, the absence of traverse grooves and the rigidity of the tread ribs, the tread has been optimised for low rolling resistance and low noise emission.

In this way, precise handling properties and safe braking distances on wet surfaces were achieved as well. The very flat tyre contour prevents the tyre’s belt elements from moving more, thus further reducing rolling
resistance. The side wall has also been designed for low energy consumption. Here, the developers did not use the usual edges and design elements in order to keep air resistance as low as possible.

By reducing rolling resistance, Continental aims to cut the energy required by e-cars and thus increase the
operational radius of this new type of vehicle. The extended range this makes possible will significantly
increase end-consumer acceptance of these vehicles, while at the same time reducing the energy used per 100 km and the time required to charge the batteries.(PRA)