Making a movie inspired by Danny Lyon’s 1968 photojournalism book “The Bikeriders” offers a filmmaker everything except a sure thing.

A one-time member of the Outlaws Motorcycle Club, photographer and (later) documentary filmmaker Lyon turned the aesthetic notion of Robert Frank’s “The Americans” outside in, capturing images not as a penetrating outsider but a watchful insider.

From this book, working in a spirit of homage, writer- director Jeff Nichols has made an absorbing feature that goes its own way. This is his most visually fastidious film, re- creating images straight from Lyon’s book. The storyline won’t be enough for some audiences; it’s a hangout movie more than a propulsive experience. Yet it lingers in the memory, raising questions about fact versus invention, and the romance of ’60s motorcycle culture versus the cost of all that fossil-fueled freedom.

Outlaws no more, the characters in “The Bikeriders” go by the fictional name of the Vandals, though a key handful of characters carry over from real life.

That starts with Kathy, the tough, perceptive wife of the most charismatic and movie-starry of the Vandals. Jodie Comer plays her, in what you might call a “dialect- forward” turn with a vocal characterization based on Lyons’ interview recordings of the real Kathy. The British actor is exceptionally deft at dialects of all kinds; if there’s anything getting in the way of her terrific performance, it’s the way Nichols uses Kathy as our reiterative tour guide into the subculture.

Comer’s also marvelous and committed, and she’s not alone. I’d call Austin Butler, who plays Benny, more of a marvelous presence than a nimble actor, but what he’s doing in “The Bikeriders” is what the storyline needs: a paragon of cool, torn between two people who love him.

The narrative sets up a triangle with Kathy vying for Benny’s devotion with Johnny, the Vandals club leader (Tom Hardy). Those who elect to leave the Vandals brotherhood rarely live long, since the rules of conduct prevent it. Benny can’t leave, he thinks, though as brutalities and injuries pile up, Kathy can’t stomach what’s happened to him, and them. That’s the chief tension element in “The Bikeriders.” Benny owes his fealty to Johnny, who’s growing older and getting tired. As the ’60s roll on, the club opens its membership to younger, less obedient outlaw wannabes, many coming home from Vietnam with terrible PTSD.

In Lyons’ book, and in Nichols’ movie, the distinction is drawn between the guys who got drunk and violent, and the guys who got high, often on heroin, and got really violent. The Vandals’ house parties grow increasingly sinister as the decade descends into political bloodshed, seemingly taking place on another planet.

Nichols only solves so many of the challenges in adapting a photo monograph into a two-hour drama. There are moments when the dialect collisions get pretty wild. But there’s real texture in the acting. Nichols has yet to make an uninteresting film; this one’s a stimulating mix of myth and realism, and keeping Comer at the core was a very smart move.

MPA rating: R (for language throughout, violence, some drug use and brief sexuality)

Running time: 1:56

How to watch: In theaters