A wheel structure includes a tire, a hub, pads and fastening elements. The tire has a hollow body with a pair of hub holes to receive the hub therein. Each hub hole is provided with an engaging wall and a securing edge extending outwardly form the engaging wall. The hub has a pair of confining sections at respective ends. Each confining section has a confining groove with a plurality of holes thereon. Each pad is formed with a plurality of locating holes corresponding to the holes of each confining groove so as to secure the pads to the hub and to restrain the tire to the hub securely.