‘I’ve never had a bike before,” says a teenage boy, grinning from ear to ear. This earnest, likable drama is inspired by the real-life amateur cyclist Greg Townsend, a teacher at a Colorado young offenders educational institution. For years, Townsend led boys on 700-mile bike tours from Denver to the Grand Canyon, sleeping out under the stars. His story has been fictionalised here into a formulaic sports movie that unfolds predictably, exactly on cue, with no surprises or upsets. But I warmed to its sensitivity; it possesses an insistence that these difficult boys are vulnerable and scared kids (undermined only slightly by the fact that the actors playing them look well into their 20s).

Matthew Modine is Townsend, who understands childhood trauma. In flashbacks, we watch him repeatedly beaten up as a boy by his physically abusive father. Not that he is touchy-feely exactly; Townsend is a firm believer in discipline and hard work. His young psychologist colleague, Haddie (Cynthia Kaye McWilliams), rolls her eyes at his discipline-heavy teaching approach.

Townsend assembles a peloton of four newbie cyclists from his welding class. There is a nervous boy with an eating disorder and a couple of lads whose bickering is constantly on the brink of becoming physical. Trickiest of the bunch is Woolbright (a nice performance by Jahking Guillory), who has serious problems with authority, but underneath it all is angry and frightened). None of the lads will wear Lycra bib shorts; Haddie is driving the support van.

The odds of making it to the Grand Canyon look slim. But Townsend is a believer in the power of the peloton, grit and team work. As I say, the ending is never in doubt. Still, the film never tries to pretend that this two-week-or-so tour leads to redemption. There is no claim that cycling can miraculously fix the long-term effects of trauma, loss and abandonment, though it may help with self-esteem and confidence. The film leaves a bittersweet taste.

• Hard Miles is in UK and Irish cinemas from 31 May.