Got a Friend who has Couple Brand New Tires--235/45-17 He said He's Give me for a few favors I've done for him. Thing is, I still have all my Stock 215/50-17s on and they are Fine. The question is: Could I put these on the Back Wheels w/o any problem or shoud I just look at purchasing couple more of the same size ?

 

do not mix, you will lose control under hard driving!...

by same 4-tires for the 4 rims!

 

Oh yes. Strict unless the car comes from the factory that way.