A vacuum cleaner has an agitator assembly, a belt drive system coupling the agitator assembly to a motor via a belt, and a belt shifting assembly which selectively shifts the belt between a drive pulley and an idler pulley on the agitator assembly. Trace rotational force transmitted to the agitator assembly when the belt is on the idler pulley is prevented from causing the agitator assembly to rotate by an anti-rotation member of the belt shifting assembly.