Perhaps it's time for the Rolling Stones to find a new lead singer.

It's hard to imagine the Stones without Mick Jagger's bray out front, but his contributions to the band have grown ever more frivolous and distracting. At the same time, it has grown increasingly clear that the essence of the Stones' sound lies not in Jagger's singing but in Keith Richards' guitar riffs and Charlie Watts' drumming. Think back to the Stones' best singles, and you'll realize it is the rhythmic tension between Richards and Watts that makes those records exhilarating.

All this is made abundantly clear on the Rolling Stones' "Dirty Work" (Rolling Stones Records OC 40250), their first album in nearly three years and their first ever under their $40-million Columbia Records contract. Taking advantage of Dave Jerden's crystal-clear engineering at Paris' Pathe Marconi Studios, Richards and Watts sound as sharp and compelling as they ever have. Unfortunately, Jagger's vocals often sound as if they were phoned in as an afterthought.

Coproducer Steve Lillywhite (U2, Big Country) has achieved a resounding smack for Watts' drums. Watts suspends each syncopated beat until the last possible moment to deliver his rifle-shot snare accents. Similarly, Lillywhite has given Richards' rhythm guitar chords a crisper sound, so their melodic content seems to linger a bit longer. On song after song, Richards' catchy guitar patterns and Watts' spare drum backing quickly establish a mood of tension and expectancy.

Then Jagger's vocal comes along. He now sings with a lot of gulped guttural tones and half-rapped lines that tend to muddle the melody. Even worse, he sings lyrics about the extremes of human behavior with no trace of desperation in his voice. When he threatens to punch someone bloody in "Fight," he doesn't sound nasty or dangerous. Instead he sounds like a comfortable old pro who's pleased that he can still assume the role of a street punk.

On "Hold Back," a litany of locker-room pep-talk phrases, Jagger adopts the trappings of passion -- a hoarse, strained voice -- without the passion itself. The result is an embarrassingly tired, hoarse vocal. Only the guitar intro and tag hint at the song's possibilities.

Jagger's lyrics are also a problem throughout the album. When they don't resort to tired cliche's, they endorse a rather ugly form of social Darwinism from the macho posturing of "Fight" to the smug amorality of "Winning Ugly." Even this wouldn't be so bad if Jagger infused these impulses of the id with some real conviction, but both the lyrics and vocals are too perfunctory for that. Even if you didn't know that Jagger is a middle-aged limousine dandy, this tough-guy posturing would sound contrived.

For all its flaws, the album still has its moments. The first single is an appealing update of Bob Earl's "Harlem Shuffle." Instead of gurgling and mumbling, Jagger sings the melody with a sensual ease. When he advises the dancers to "move it to the left . . . move it to the right," Richards' sharply chopped guitar chords push the hips one way and Watts' drum shots knock them back the other way.

As if to prove he can still sing with real conviction when he wants to, Jagger rouses himself for one great performance on "Had It With You." Richards and Watts lay down one of their most mesmerizing rhythm tracks, and for once, Jagger sings with them instead of against them.

Jagger has shown more interest recently in his solo singing and acting careers than in his old band. In the highly unlikely event that the Stones were to go on without Jagger, Richards would not be the best replacement. Though he does a surprisingly good job on his two songs from "Dirty Work," his whiskey-ravaged voice is only tolerable in small doses.

No, the Rolling Stones need a front man whose songwriting and singing can match the rhythm section's brashness and unquestionable conviction -- just as Jagger's once did. Maybe Keith Richards can get hold of Graham Parker's phone number.