What is caused by driving with winter tyres during the summer months?

Your answer is correct because driving with winter tyres during the summer months can indeed lead to increased fuel consumption and tyre wear.

Winter tyres are designed for colder temperatures and provide better grip on snow and ice. However, when used in warm weather, they can wear out much faster due to their softer rubber compound, leading to excessive wear. Additionally, the rolling resistance of winter tyres is generally higher in warm conditions, which can result in increased fuel consumption.

While driving stability may not be directly impacted as significantly in dry conditions, it can still be affected by the reduced performance characteristics of winter tyres at higher temperatures. Thus, the combination of fuel consumption and tyre wear is key to understanding the impact of using winter tyres in summer, in accordance with German traffic regulations that promote safe driving practices.