Here's the thing -- the Sheen ARE their bikes. Literally. They're made of some kind of fluid chrome matrix that means they can remake themselves into anything they choose. And what they choose is to tear ass on two wheels.
The Sheen don't work with anyone -- hell, they don't communicate with anyone, either. They're robo-punk teens with attitude and no interest in organic life. Their entire existence is built around some deity they call "Jaimsdeen."
He who can cross the land, controls the land. And somehow, Gila Bill's crew keeps their tugboats running better than any of the other crews scrabbling for control of the desert. That puts him on top.
This is a detestable crew of animutes run by Gila Bill, a local warlord who's literally cold-blooded. They keep the peace, when it suits them. But they're also raging xenophobes against anything without a tail, so...