The car tyre with different specification, structures and wear degree can't working together, or it will affect the controllability and stability of the car. In order to give maximum play to the design performance of our car, we would better to choose the four same tyre, at least with the same specification and control in the coaxial. If the new car tyres you bought are same with the remain tyres on your car, we advise to install the new car tyres on the back axle.
If just replace one new tyres, we also advise to install the new car tyre on the back axle.