Search new + high quality used tires online. Size 315 30 R21 starting at: $47.99. Tires in stock: 165. Available brands: 4 with 18 models. All season: 57. Winter: 11. Summer: 97.. 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!