Search new + high quality used 255 40 R21 Continental tires online, starting at: $44.59. 255 40R21 Continental models in stock: 6. All season: 12. Summer: 81. Run flat: 1. 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!