When it was announced, a few months after they’d all performed "Walk This Way" on an MTV awards show, that Aerosmith, Kid Rock, and Run-DMC would be touring together, the only question was exactly how many times "Walk This Way" would be played each night. A week ago last Thursday at the Tweeter Center it was done twice, as the first and the last song of the evening, and there was something vaguely Spinal Tappish about the symmetry of that equation. No complaints here, though: I’m not sure I heard anything in between that was better.

Run-DMC are the first hip-hop group to make a living from touring, even though their performances are perfunctory. DMC is buff but has lost his voice; Run sounds exactly the way he used to but has grown fat, bitter, and religious. After they opened with "Walk This Way," you half expected them to call it a night, but they spun it into "It’s like That" into "Tricky" into "Mary, Mary." Then Run set up "King of Rock" with a sidewalk sermon on the importance of Run-DMC. Which was unnecessary. All he had to say was that Run-DMC, like AC/DC (their true rock analogue), cannot be improved upon — they can only be followed.

In any case, at that moment Kid Rock and his entire band materialized in a puff of smoke and stole the show. This moment was obviously choreographed, but it still felt like an invasion. The impression you got was not only that Kid Rock was proclaiming himself the King of Rock but that he was stealing the crown right off DMC’s bald head. After a joint "King of Rock," Run-DMC were ushered off stage and Kid Rock launched into, of all things, "Sweet Home Alabama." Look, I’m not saying Kid is a bad Kid. But if you bogart "King of Rock" — a song that reclaimed pop supremacy for young black urbanites — and follow it up with a reactionary redneck anthem that you didn’t even write, some people might think you were being a bit of a smart-ass.

Kid’s second song was Metallica’s "Sad But True" (Kid’s version is called "American Bad Ass"), and after it was over, a friend pointed out that Mr. Rock still hadn’t played one of his own songs. The thought that crossed my mind was, "Be careful what you wish for" — but almost every time Kid and his band set out to play one of their own songs, they segued into someone else’s: ZZ Top, AC/DC, Zeppelin, even a couple of verses of "Freebird," which should give you an idea of the Kid’s commitment to crowd pleasing. His was a distillation of every trick in the showman’s book: scantily clad women, pyro, call-and-response, self-congratulation, sentimentality, the Prince-derived spectacle of playing every instrument on stage in a single song, and even a carbon copy of the James Brown throw-off-the-cape routine. It was delirious and utterly sincere in the way only desperately needy show biz can be; if there’s anyone in rock right now who’s begging for a year’s engagement in Vegas, it’s Kid Rock.

After that, I was ready to go home. I mean, Kid Rock is exhausting. Aerosmith are the opposite: they’re invigorating. Even if you never bought an Aerosmith album in your life, you can probably hum along from memory with every song they play on a given night. This was the illusion that Kid Rock was striving for, but Aerosmith were a reminder that there’s no substitute for catalogue, charisma, and charm. They’re five old guys with only one special effect, a preening, human-helium-balloon of a singer named Steven Tyler. They have nothing left to reveal, and by necessity their success lies in transforming the known into the majestic.

The image that stays with me comes from a quick, three-song set ("Big Ten-Inch Record," "Dream On," "Mama Kin") they played on a small stage erected near the lip of the Tweeter’s roofed pavilion, facing out into the lawn seats and a torrential downpour. Back-lit and viewed from behind, the gesture felt generous and looked marvelous — hands in air, screaming faces, a sliver of rain carved by a white beam of searchlight. An obvious notion, but the songs were well played, and they carried it off with such style that it felt perfectly natural. Theirs is a deceptively simple gig: just go out and be Aerosmith for a couple hours. Nice work if you can get it.