Brand: American Roadstar Model: Sport A/S Size: 315-40R21 315/40-21 315/40R21 315/40/21 315-40-21 315 40 21 3154021 Tread Depth: 10/32 Treadlife: 50,000 miles Season: All Season Performance: High Performance Car Type: Truck/SUV Load and Speed Rating: 111Y Speed Rating Description: Speed Rated Up to 186 mph Section Width: 315 Aspect Ratio: 40 Rim Diameter: 21 Production Year (DOT): N/A