Throughout Equestria, there is a high amount of respect and knowledge for this pony. A brilliant mental revolutionary in the scientific field, he has devised and built many inventions that are effective substitutes for magic. His main talent isn't inventing, though. It's making ponies think outside the box.
His live-in assistant/adoptive sister is Silver Link, a mare that usually keeps Gearhead on the right track with his ideas, even if she herself can be just as wacky as her brother. And even then, the mare sees him as a father more than a brother.
Both his wings and forelegs were viciously removed in an attack by a mad thunder dragon in Cloudsdale years ago, which said dragon was defeated with the combined forces of himself, Sonic Speed, and Roy G. Biv, both of whom are Rainbow Dash's grandfathers through her parents, Firefly and Bifrost (though he prefers Prism Ash) respectively.
The leg prostheses were fashioned exactly as regular pony legs would work, and have a feature where the hooves can shift into articulate clawed hands, similar to a griffon's. The wings are highly effective, and are able to be detatched for routine inspections and if Gearhead feels the need to wear a different set of wings if he wants to. By far he is not the fastest pegasus in the skies, but he is one of the toughest.
Although he was never looking for a special somepony, he found himself drawn to Princess Luna, an echoing memory of unknown nostalgia when with her.
His past is mysterious, and even he doesn't know much about his family, aside from what his ancestors have done for society. He has his own private library filled with historical accounts and books found nowhere else in the world.
In EQG, he is a respected professor at Canterlot High and someone the students can always talk to about their problems. He is not above reprimanding students when things happen, and does not turn a blind eye to the happenings around the school. He is good friends with the custodian Diz Q. Disarray, and has been known to go over Principal Celestia's authority on certain matters. He also has some very big secrets that no one knows about…