Search new + high quality used 235 45 R18 Firestone tires online, starting at: $49.38. 235 45R18 Firestone models in stock: 6. All season: 10. Winter: 2. Summer: 2.. Selling all used tires at discount costs. All used tires go through 2 layers of inspection on specialized equipment. One year warranty + free shipping on all inventory ;) Happy shopping!