I dont know if i did right, Yesterday i bought Federal 595 RSR for my rear tires 245/35/18, this model are semislick. I am keeping the front with OEM tires runflat bridgestone potenza. In conclution, i have runflat in the front and non runflat semislick at the rear tires. I didnīt change the front ones because they still have 70% of life. I will appreciate your oppinion about having runflat in the front and regular semislick at the rear tires and also if anybody has tried this tires, please share experience. Later on i will post some pictures.