Link wheels are nothing but a group of websites that are interconnected which try to improve the ranking of a target website by linking to target website. For example if you have 50 websites in your link wheel and the website you are targeting is "yourdomain.com", then:
Site 1 links to Site 2 and back to the "yourdomain.com"
Site 2 links to Site 3 and back to the "yourdomain.com"
Site 3 links to Site 4 and back to the "yourdomain.com"
...
Site 13 links to Site 14 and back to the "yourdomain.com"
Site 14 links to Site 1 and back to the "yourdomain.com"
Bookmarks