Blink-182 and Box Car Racer drummer Travis Barker spent some time recently running from the police. Not the real ones, but still tough people nonetheless.

"The punk rock police," Barker mused of the purest of music purists, "have a habit of barring things unless that's what they're used to. And that's not what punk rock is about. Punk rock is doing what you want to do and you don't give a f--- what anyone thinks about it."

Barker's run-in with the laws of musical experimentation came when he joined Rancid singer/guitarist Tim Armstrong and singer Rob Aston's side project, the Transplants.

The band's self-titled debut, released Tuesday, fuses drum'n'bass, reggae and hardcore with the traditional punk that fans are used to hearing from Barker and Armstrong. Although there's nothing else out there quite like it, Barker said the Transplants make perfect sense to him.

"I probably listen to more hip-hop and drum'n'bass than I do punk rock music, and same with Tim and Rob," Barker sad. "I grew up on Whodini and Run-D.M.C. and Slayer and King Diamond and the Clash. We've always loved all these types of music. With Transplants ... the record label had no expectations. We had no expectations. So we had no limitations. We could do whatever we wanted."

Some of the material on Transplants is closer to punk, like the thrashing "One Seventeen" and "Sad But True" (about losing a loved one), but other stuff, like "D.J. D.J." and "Weigh On My Mind," is dub music with a kick.

"I grew up playing jazz and Latin, not punk rock," Barker said. "I love playing every style. It's refreshing. And everything came very natural. This whole record was made for less than $30,000. My drums were recorded in four hours. So this isn't something we had a master plan for."

Just as it was recorded in a matter of hours, the music has caught on extremely fast. A few days after Los Angeles' KROQ-FM began spinning "Diamond and Guns," the quirky, piano-driven tune became the most requested song on the influential station. The song features Armstrong and Aston trading verses in their signature raspy growls, as well as a guest appearance by Son Doobie of Funkdoobiest.

Other collaborators on the album include the Distillers' Brody Armstrong (who is also Tim's wife), Rancid's Lars Frederiksen, AFI's Davey Havok and Nerve Agents' Eric Ozenne.

"It was like our friends and family," Barker said. "We didn't ask anyone we didn't know."

So why didn't his Blink counterparts get involved?

"It didn't even cross their minds," Barker laughed. "They knew it was something way out. I played them a track and they said, 'You guys are crazy.' ... Tom [DeLonge] and Mark [Hoppus] were having babies, so I stayed busy. The same month I did Box Car and Transplants I also did Black Eyed Peas (see 'Black Eyed Peas Exhibit New Breed Of Elephunk On Upcoming LP'). But they're super supportive of everything."

Barker doesn't call Transplants a side project and referred to the group several times on Monday as "a band." But it's a band he almost wasn't part of.

Armstrong and Aston were finished with the album, Barker said, "But they felt like it was missing something and decided they wanted live drums. [Armstrong] called me one day, 'Look, I got this project. I've been writing these songs for a year. You're my favorite drummer. I want you to be a part of it.' So I went down and listened to it with them and instantly liked everything. Four days later I went and recorded drums."

On the eve of the album's release, Barker was as excited as ever about the Transplants. His feelings were bittersweet, though, as Tuesday also marked the first night of a five-week Box Car Racer tour.

"Here's something we're super proud of, but you won't get to hear us play it or talk about it," Barker said.

After the Box Car Racer outing comes to a halt, Blink-182 plan to write and record their next album. Meanwhile, Armstrong is finishing the next Rancid record. By February both hope to be done so they can tour as the Transplants.