A bike movie with a difference: no Hell's Angels, no sex, no drugs. Instead, all-rounder Bruce Brown (who made the surfing documentary The Endless Summer) has come up with a feature-length commercial for good, clean motorcycling fun depicting just about every conceivable permutation of motorised two-wheel sport from ice-racing, enduro, moto-cross and road racing to the spectacular, crash-ridden American speciality, dirt-track racing. Spending some time following the progress of Mert Lawwill, one of America's top dirt-trackers, the film also has considerable footage of Steve McQueen playing at moto-cross and desert racing. It abounds with intelligently applied stop-frame, slow motion and colour treatment knick-knacks which heighten the excitement and visual impact. Though a schlocky Country 'n' Western soundtrack and facile narration irritate after a while, this is an imposing essay compared to which the outlaw biker pics are tame travesties of what the two-wheel trip's all about.