Marlon Brando played one in a movie. The Rolling Stones hired some as concert bodyguards. Today, a top American TV show stars them.
Bikers -- and the roaring, rolling, leather-clad motorcycle gangs they form -- are quintessential figures of American lore.
But these days, along with that born-to-be-wild spirit that emerged in the second half of the 20th century as a counter-culture scream, come crimes like weapons and drug trafficking. So do spasms of violence when gangs clash, as they did over the weekend in Waco, Texas.
Members of as many as five gangs turned a restaurant and parking lot into a veritable war zone as they fought with knives, chains, clubs and guns. Nine were killed and 170 were arrested.
A group of gangs had arranged to meet at the restaurant and an uninvited one showed up. Among other possible, initial triggers to the violence, a gang member apparently had his foot run over in the parking lot, Sergeant Patrick Swanton, a Waco police spokesman, said Tuesday.
The US government -- and motorcycle aficionados themselves -- is quick to point out that the vast majority of enthusiasts who form riding clubs are law abiding people who simply share a love of bikes, engines revving and the open road.
The Justice Department uses the term "outlaw motorcycle gangs" to single out ones that use their clubs as vehicles to commit crime, such as drug and weapons trafficking and cross-border drug smuggling.
Perhaps the best known of the gangs, the Hell's Angels, in addition to drugs, is also involved in assault, extortion, money laundering and homicide, the Justice Department says.
That's a far, far cry from Brando character Johnny Strabler's famed wisecrack in the 1953 film "The Wild One," in which Brando plays the leader of the Black Rebels -- one of two rival motorcycle gangs that wreak havoc in a small California town.
Asked by a young woman dancing to juke box music "Hey Johnny, what are you rebelling against?," Brando's character, tapping his hands to the beat, billed cap tipped at a rakish angle, sneers and replies: "Whaddaya got?"
- More than 300 in US -
Today there are more than 300 active outlaw motorcycle gangs in the United States, "ranging in size from single chapters with five or six members to hundreds of chapters with thousands of members worldwide," the Justice Department website says.
Outlaw motorcycle gangs represented just 2.5 per cent of all gang members in the United States in 2013, according to the FBI's National Gang Intelligence Center.
A total of 88 percent were street gang members and 9.5 percent were prison gang members, it said.
But it said the proportions might be misleading. The FBI report said "OMGs are more problematic than their modest numbers suggest. This is likely due to their solid organizational structure, criminal sophistication, and their tendency to employ violence to protect their interests."
The Bandidos, one of the gangs involved in Sunday's mayhem in Texas, is one of the biggest in the United States -- with some 900 members and 93 chapters, according to the FBI.
Over the decades, Americans seem to have been fascinated by this phenomenon. Counterculture icon Hunter S. Thompson embedded himself with the Hell's Angels to write a book about them that was published in 1966.
Even today, the TV show "Sons of Anarchy," about a motorcycle club in a fictional town called Charming, is wildly popular.
Academics who have studied these gangs say they started forming after World War II: US combat veterans returned home in huge numbers, found the transition to peaceful civilian life dull and hard to digest and missed the camaraderie of their military unit.
Military severance pay was good for buying a bike and hanging out in bars.
"Thrill-seeking attracted some returning veterans to choose a saloon society lifestyle centered around motorcycles," writes James Quinn, a professor at the University of North Texas who has studied motorcycle gangs.
"Positive views of military experiences, and the intense camaraderie they bred, also made such a lifestyle attractive," Quinn added.