Search new + high quality used tires online. Size 315 40 R21 starting at: $34.99. Tires in stock: 79. Available brands: 9 with 23 models. All season: 59. Winter: 2. Summer: 18.. 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!