The Mojave Boot-Riders (simply referred to as the Boot Riders by members) were a nomadic tribe inhabiting the Mojave, before their evolution into the Chairmen.
One of the many nomadic tribes that formed out of the ruins of the Old World, the Boot-Riders inhabited the ruins of Las Vegas. Their situation dramatically changed when they were approached in 2274 by a Securitron. The tribesmen destroyed it in a "minute flat". The following day, twenty Securitrons approached them and they were forced to negotiate with Mr House. In return for shelter, food, and medical care (all the things a nomad always needed), they would settled down, renovate The Tops, and work with Robert House to establish the city of New Vegas. Most of the tribe was against settling down, with the most vocal critics being its chief, Bingo. Benny, on the other hand, saw it as an opportunity.
The disagreement over this issue eventually let to a confrontation between Benny and Bingo. The latter challenged Benny to a ritual knife fight over the leadership of the tribe. The fight went down three days after House had made his proposal. Benny's superior skill with a knife left him as the victor and new leader of the tribe. The tribe moved to Vegas and began renovating the Tops, bringing it back to life. As they worked, a number of House's Securitrons dropped off boxes with suits, ties, and wingtip shoes, together with a message from their employer announcing they were the Chairmen now. The tribe was in uproar over the new name, but Benny used his authority to force them to accept it. As he put it, it was "ciao to the old ways" and "time to swing in style."
Mojave Boot-Riders as such are mentioned in Fallout: New Vegas and actually appear only as the Chairmen. The actual Boot Riders before they became the Chairmen are shown in the All Roads graphic novel.
↑The Courier: "What were the original names of the other tribes?" Robert House: "The Chairmen, as we know them now, went by the unfortunate appellation of the "Mojave Boot-Riders." They were nomads, too. As for the White Glove Society, I afraid I'm contractually obligated not to reveal their original name." (Robert House's dialogue)
↑ 2.02.1The Courier: "Was your tribe always called the Chairmen?" Benny: "Nah, in the way-back we called ourselves the Boot Riders. Silly name, but that's how we rode the Mojave, dig? - on our feet. We were nomadic badasses, not to be trifled with. A gang of ruffians, though with a certain panache. When House gave us the Tops to renovate, his robots dropped off boxes full of suits and ties and wingtip shoes. Told us we were the "Chairmen" now. That caused an uproar. But I said "the name sticks." Ciao to the old ways, baby - time to swing in style. If the shoes fit, you wear them." (Benny's dialogue)
↑The Courier: "How did Mr. House introduce himself?" Benny: "We were east of Vegas when the first Securitron we ever saw rolled up on us. We junked it in a minute flat. The next day twenty roll up. So we listened. Said we'd been selected. Vegas needed us to defend it. In exchange, we'd get cushy digs, full stomachs, medical treatment. Everything a nomad never gets, in other words. Most of the tribe thought we should say no. I thought it was the best idea ever." (Benny's dialogue)
↑The Courier: "How long were you the head of the family?" Benny: "Seven years. Took over three days after Mr. House introduced himself. Our chief at the time, mountain of a guy named Bingo, wanted to stay nomadic. I disagreed, so he challenged me to the knife. He looked so surprised when I stuck that knife in his neck. Thought he was so tough, but he was so slow. That's how I made chief. It's how things were back then." (Benny's dialogue)