Search new + high quality used tires online. Size 315 30 R21 starting at: $44.32. Tires in stock: 241. Available brands: 4 with 21 models. All season: 67. Winter: 29. Summer: 145.. 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!