"Roll Bounce" is a nostalgia-filled look back at coming-of-age in the late-'70s era of disco music, head radios, "Star Wars," and, most prominently, roller skating. When the film sticks to the swirling neon lights of the Sweetwater Roller Rink, where talented teenage skater X (Bow Wow) hangs out with his trash-talking friends, the film really cooks. There is nary a sign in sight of present-day slang or explicit sexuality or language, and director Malcolm D. Lee (2002's "Undercover Brother") brings an affectionate innocence to the way he views his young characters, hesitant and unsure of themselves as they interact with the opposite sex and still in search of who they are. He also uses an excellent soundtrack of wall-to-wall '70s classics to accentuate the light, all-in-the-name-of-fun mood.

Unfortunately, Lee opts to wander away from the skating Mecca for too long and too often, and that is where he runs into trouble. Even by the standards of a roller skating-centric movie—a fairly limited genre, and for good reason—the screenplay, by Norman Vance Jr. (2005's "Beauty Shop"), is pure cornball, and not in a good way. As the summer of 1978 presses forward in the middle-class Chicago suburb where he lives, X only really feels happy when he's skating because—wait for it—he still hasn't gotten over the recent death of his mother. Add to that a rocky home life complete with a preoccupied father (Chi McBride) in denial who secretively has been jobless for months and takes out his frustrations on his son, and no wonder X prefers losing himself at the rink across town.

This commonplace subplot involving the loss of a parent can be done well with a careful hand (as in 2005's "Because of Winn-Dixie," for example), but here it is driven into the ground over and over with such mawkish emotions and bombastic instrumental strings that it comes close to producing unintentional laughs. The film's worse scene finds X dealing with his anger by taking a bat to his dad's car, only for them to tearfully embrace, destroyed property, smashed windows and broken headlights be damned; it rings with such falseness that it severely detracts from all the good that has come before. Indeed, it is all downhill from there (starting around the end of the second act), with a climactic roller skating competition, followed by two more skate-offs between X and his friends and reigning skating god Sweetness (Wesley Jonathan) and his cronies, that doesn't know when to quit.

If the teenagers inhabiting "Roll Bounce" are fairly realistic creations in the way they act and speak around each other, few of them escape being anything more than broad one-dimensional types. X's buddies are mostly set apart by a single distinguishable trait—Mixed Mike (Khleo Thomas) is often heckled about his half-white/half-black race, Naps (Rick Gonzalez) has a large, unwieldy afro, etc.—and the lone female friend, brace-faced new girl in town Tori (Jurnee Smollett), transforms from a supposed ugly duckling into a gorgeous swan by the end. The problem with this is that Tori is clearly pretty right from the start (aren't they all in the world of movies?), and director Malcolm D. Lee makes the mistake in suggesting a possible romance between she and X that never comes to light. It's almost as maddening as the finale of "Pretty in Pink," when best friend John Cryer, madly in love with Molly Ringwald for the whole film, was thrown to the wayside so she could run after rich boy Andrew McCarthy. This misstep with her character notwithstanding, Jurnee Smollett (1997's "Eve's Bayou") brings a natural joy and light to her role, and possibly gives the film's most solid performance.

The rest of the actors are a mixed bag, most of them either off their regular game or glaring novices. As protagonist Xavier, X for short, Bow Wow (2004's "Johnson Family Vacation") is passable without being a whole lot more than that, and Chi McBride (2004's "I, Robot") wavers between believably sincere and unevenly low-key as his put-upon father. As girl-of-X's-dreams Naomi, Meagan Good (2005's "Venom") is physically cute and emotionally vacant, reciting many of her lines as if she is unsure she's getting them right. Better is Wesley Jonathan (2004's "The United States of Leland"), who gives X's rival of Sweetness a self-deprecating, over-the-top humor that goes along well with his extreme narcissism.

Running past the point of palatability at close to two hours, "Roll Bounce" is great in a silly, breezy, purposefully cheesy way for about 45 minutes of the time, mostly when the top-notch '70s oldies are blaring over the soundtrack and the wheels are rolling across the rink's wooden floor. The rest of the film, overstuffed with side plots that either go nowhere, take up too much time, and/or are as sappy as an oak tree, do no favors to a motion picture that demands simplicity and a speedy pace. It can be assumed that potential viewers of "Roll Bounce" will be going for the skating and the music, and they'll get that in sporadic clumps. What they will have to sit through in order to sift out these peppy, nicely sentimental moments of adolescence, however, eventually becomes more chore than fun. There's a nice little gem of a movie hidden within "Roll Bounce," and a tired, needlessly schmaltzy one that ultimately shields it from ever breaking through as it should.