The Shepherd Hardware flat free replacement tires provide a cushioned ride that can also withstand punctures from common objects that cause flats. This helps eliminate all downtime related to flat tires. These tires are extremely durable and can last up to 10 times longer than standard air filled tires. The shepherd 9708 model features a 15″ diameter wheel with a 3-3/4″ knobby tread face and a 500-lb load capacity, and a 5/8″ centered bore.