Mixing tyres is not recommended however if you do, please make sure that you stick to the same size on each axle. The rear tyres must be the same wheel diameter size as the front tyres. New set should be fitted on the Rear Axle.
Replacing a single tire on a vehicle can have an adverse effect on suspension systems, gear ratios, transmissions, and tire tread wear. If a single tire replacement is unavoidable, it is recommended that the single new tire be paired with the deepest tread tire from the vehicle (including the full size spare) and both be placed as a pair on the rear axle of the vehicle.
Fact: New tyres provide better wet grip than your half-worn tyres. When new tyres are installed on the rear, it helps reduce the potential for your vehicle to fishtail and lose stability in wet conditions. However, not only does the greater tread depth in the back help maintain control in wet and slippery conditions, as a driver, you are better able to “feel” feedback from the tyres through the steering wheel when the worn tyres are in front.