Changing lead singers midstream tends to have an adverse effect on most rock bands, but Van Halen topped the charts with 1986's 5150 after original vocalist David Lee Roth left.

Two years later, they released their eighth LP, OU812 – and the hits kept right on coming.

With 5150, the questions on most fans' minds were how well new singer Sammy Hagar would fit in with the group and how his presence would affect the pop shift they had started pursuing toward the end of Roth's tenure. By the time OU812 arrived on May 24, 1988 – with a title that seems to take a shot at their former lead singer – fans knew what they were getting with Hagar-era Van Halen.

The only real mystery was whether they'd be able to sustain their momentum – a riddle they solved with the release of the album's first official single, the Top 5 pop hit (and rock-radio chart-topper) "When It's Love." While that track was one of the era's many synth-padded power ballads, the album made room for more than keyboards.

Listen to Van Halen's 'When It's Love'

OU812 offered an expansive mix of sounds that included moody rockers ("Mine All Mine"), uptempo numbers ("A.F.U. [Naturally Wired]"), radio-friendly pop anthems ("Feels So Good"), a bluesy acoustic tune ("Finish What Ya Started") and even a Little Feat cover ("A Apolitical Blues").

They ran the risk of alienating some fans by straying so far afield from their classic sound, but the sales were nothing but encouraging: OU812 followed 5150 to the top of the Billboard charts, going quadruple platinum and spinning off four Top 40 pop hits along the way.

Firmly reestablished as one of the biggest rock bands on the planet, Van Halen closed out the '80s on a high note, and when they returned with For Unlawful Carnal Knowledge in 1991, they picked up right where they left off, debuting at No. 1 with a triple-platinum record that contained no fewer than seven hit pop and/or rock-radio hits.

For a while, it looked like there was no stopping them. Of course, they'd eventually be derailed by Hagar's departure in 1996 (followed by a whole bunch of other stuff), but OU812 still stands as one of the group's most successful records, not to mention one of the decade's smoother blends of heavy rock and light pop sheen.

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