Where are you not allowed to use retread tyres on 100 km/h buses?

In German traffic regulations, retread tyres are not allowed on the front axle of buses that travel at speeds of 100 km/h or more. This is because the front axle is responsible for steering and bearing a significant part of the vehicle's weight and forces during driving. Using retread tyres there could reduce grip and safety. On the rear axles, retread tyres may be permitted under certain conditions because they mainly provide traction and support, but the front axle requires new, reliable tyres for safe handling.