On the remix for "Kick Push," a hip-hop paean that has been all over urban radio and Black Entertainment Television, Chicago MC Lupe Fiasco and producer-rapper Pharrell Williams trade rhymes detailing an unexpected slice of life in the streets: skateboarding.

Fiasco raps about skateboarding as a form of rebellious self-expression, peppering his vocals with the names of street-skating tricks and common injuries — even some intricacies of skateboard-borne romance. "I don't think this board is strong enough to carry two," he informs a girlfriend.

Williams, by contrast, fills his rap with a prickly issue of racial identity: the loaded condition of being a "black skater from the 'hood."

With the popularity of so-called "skateboard rap" like "Kick Push," the divide separating America's two most influential street-based subcultures is narrowing. Skateboarding, that quintessentially suburban "extreme" lifestyle sport, and hip-hop, in which street credibility is often measured by gunshot wounds and time served, seem to be having a "your chocolate is in my peanut butter" moment.

Skateboarding and hip-hop started kicking each other's tires in the early '90s when skaters adopted rappers' baggy-jeaned look and hard-core rap replaced punk rock as the de-facto soundtrack to the X Games. In the abstract, the two cultures seem to exist in parallel universes — not least because one is overwhelmingly white and the other overwhelmingly black. Yet both share an in-your-face immediacy created by disenfranchised youth. And, not coincidentally, skaters and rappers have turned raging against the machine into multibillion-dollar businesses with global reach.

Skateboard rap arrives at a moment in which hip-hop's most nimble lyricist is white (Eminem) and the fastest-rising star in reggae is a Hasidic Jew (Matisyahu). So what's so strange about Williams becoming a jewelry designer for ultra-luxury goods purveyor Louis Vuitton while changing his nickname to Skateboard P?

Williams is better known as part of the hit-making producer duo the Neptunes, which has helped craft hits for Gwen Stefani, Mariah Carey and others. But leading up to the July release of the rapper-producer's first solo album, "In My Mind" (which reached No. 2 on the album chart this summer), he took to calling himself Skateboard P in interviews and on songs — a transformation no less dramatic than David Bowie's 1972 metamorphosis into Ziggy Stardust.

Williams said he feels justified, in part, by his sponsorship of a skateboard team that has appeared in several of his videos and at events such as November's Vibe Awards.

"Most people think skateboarding is for some kid with blond hair from suburbia," Williams said. "But it's not just that. Skateboard culture is not white or black. Neither is hip-hop."

Berkeley, Calif., teenage rap quartet the Pack already have scored a modest radio hit with their ode to skateboard footwear, "Vans." Group members insist their skate-rap mash-up isn't some novelty hook — they've been skating since junior high. The song's video splices footage of fleet-footed skaters doing kick flips and rail slides at a skate park with scenes of "hyphy" rap enthusiasts extravagantly break-dancing in an alley.

And Fiasco, who was on the cover of July's Billboard riding a skateboard and rolled on to his debut BET performance on one, will release his highly anticipated Atlantic Records debut CD, "Lupe Fiasco's Food & Liquor," this month.

According to Jake Phelps, editor of skateboarding's journal of record, Thrasher magazine, the sport always has been multicultural. "If you're down with skateboarding, it's like the United (Colors) of Benetton out there, bro," he said.

But he wasn't surprised rap music would look to skateboarding for validation. "Hip-hop's kind of commodified now. How real can you keep it? Connect the dots," Phelps said.

The perception lingers, however, that skating's endless-summer image and hip-hop's ethos of "keeping it real" remain fundamentally at odds. On a bulletin board for the hip-hop blog nahright.com, one recent poster sounded off on Williams' and Fiasco's contributions to rap. "Save hip hop," he wrote. "Don't listen to skater rap."

Even Fiasco, the Muslim rapper of West African descent (real name: Wasalu Muhammed Jaco) who has become the poster boy of hip-hop's latest sub-genre, is reluctant to pigeonhole himself as a representative for skateboard rap. Never mind that his design company, Righteous Kung Fu, creates graphics for skateboard decks or that "Kick Push" was intended as a promotional song on a DVD for a Chicago-area skateboard shop.

"As a rapper, you can only go in so many different directions," Fiasco, 24, said on the set for his next single, "I Gotcha." "You can be a gangsta rapper. You can be a cool braggadocio rapper. You can be a hustler. This is just me. I'm a nerdy, skateboard-riding guy who loves fashion and art."

He added: "When you start representing a culture, it gets stigmatized as being phony."

Case in point: The T-shirt company Plain Gravy has begun selling a $32 T bearing the phrase "Pharrell Can't Skate" — the implication being that Skateboard P is using his identification with skate culture as merely a marketing device.

Williams, 33, dismisses any questions of his commitment to the skateboard/hip-hop overlap. The rapper-producer spent his preteen years in Virginia Beach, Va.'s, Atlantis Apartments housing project, then moved with his family to the suburbs, where he first encountered things he had only heard about — Rice Krispie treats, soccer moms and, most important, skateboarding. He became a skater and credits the lifestyle with shaping his worldview. Further, Williams cites his co-sponsorship with Reebok of the Ice Cream Skate Team as proof that he wants to hybridize the cultures, to show black kids that there are alternatives to the gangsta lifestyle. Not coincidentally, four out of five team members are black.

"I send 'em around the world, I put money in their pockets," he said. "I'm trying to open the door so other people can come through and help spread the culture — to offer kids in those areas an alternative. You can do a trick on a skateboard and be cool and earn money. The chicks will love you — just like you're selling dope."