Search new + high quality used tires online. Size 315 40 R21 starting at: $25.4. Tires in stock: 299. Available brands: 9 with 30 models. All season: 247. Winter: 4. Summer: 48.. 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!