SAN JOSE — There were elegant 1930s-style bombas with candy-colored paint, menacing rat rods, classic 1962 Chevy Impala convertibles of the lowriding golden age, and a car-hopping contest won by a 1984 Oldsmobile Cutless that pumped itself nearly 5 feet above the asphalt.

Decades before Silicon Valley tech companies began developing self-driving cars, this was the region’s most enduring automotive innovation — stylish lowriders that bounced up and down as they cruised along Story and King roads in East San Jose on weekend nights.

“Before the Internet, cruising was the thing to do, whether you had a lowrider or not,” said Jose Valle, 32, who calls himself “The Homeboy Mad.” “It’s bigger than San Jose history, bigger than Chicano history. It’s American history. It created an explosion of entrepreneurship.”

An annual car show at the Santa Clara County Fairgrounds on Sunday was a tribute to one of those entrepreneurs: Sonny Madrid, the founder of Lowrider Magazine who died in June after a two-year battle with cancer.

While most scholars have traced the roots of Mexican-American custom car culture to East Los Angeles in the mid-20th century, Madrid and his South Bay friends helped spark the global spread and commercialization of the scene while also connecting it with the political activism of the Chicano Civil Rights Movement when they published their first edition in 1977. Body shops devoted to the slow-and-low driving trend opened up across the South Bay, as did businesses that sold hydraulic kits worldwide.

“Sonny was our Yoda, our Obi Wan Kenobi of lowriding,” said Isaac Ramirez of San Jose-based StreetLow Magazine, which hosted Sunday’s event.

Early editions of Lowrider had stories about police discrimination, social justice and indigenous culture, but the magazine grew more popular — and controversial — when it began draping its cars with bikini-clad women in 1979, a tradition that continues to this day — though not at Sunday’s event.

Hundreds of souped-up vintage cars — some sizzling in the hot Labor Day weekend sun, others in warehouse showrooms — were on display at the family-oriented festival.

Crowds gathered around a gated pen to watch two hydraulically powered cars battle against each other in a hopping contest. When he was a kid, 53-year-old Pauly Cardenas remembers using yardsticks or beer bottles to measure how high a car could jump. On Sunday, he was an official judge with a special custom-made “hopstick” to decide the winner.

Some car owners prize their vehicles too much to let them bounce around. Mike Solorzano, 53, brought his glittery golden 1939 Oldsmobile on a trailer. Worth about $70,000, the car — known as a bomba, or bomb, for its rounded shape — usually stays in his Oakley garage.

“It’s all about the work, and showing it,” he said.

The music was eclectic, but loud — an elder DJ from the Impalas Club of Salinas Valley playing electro-funk on one side of the fairgrounds, as a younger DJ spun rap on the other. Families and car clubbers huddled under tents near their vehicles, eating street tacos or barbecue food. A handful dressed in the pressed-and-polished formal style of an earlier Latino era, with vests or pompadours. Most, however, wore T-shirts and shorts to beat the heat.

Longtime enthusiasts who have been lowriding since their teenage years brought grandkids to the show.

“It’s about family, kickin’ back,” said Rambo Soto, 51, of Salinas, who was setting up a picnic as he showed off a ’64 Impala with hydraulic lifts — one of several in his collection.

Margarita Mejia, 31, of Fremont dressed in a retro “chola style” for the occasion, wearing creased-up Levi’s with baby cuffs, heavy eyeliner, wristbands that resemble a spider’s web, and a coiffed or “feathered” hairstyle.

A collector of soul and funk music, she said the event was as much about carrying on a social and artistic tradition as it was about hydraulics and chrome undercarriages. She and Valle help run the 5-year-old Soulero’s Ball Revue, hosting social events that celebrate lowrider culture and art.

“We call it carnalismo, which is brotherhood,” she said. “This is the cruising capital of the world, Story and King.”

Police over the years have suppressed the cruising tradition using a 1950s-era California law that bans low-hanging cars, relegating hobbyists to their garages, body shops and fairgrounds. But judging by all the kids and baby strollers at Sunday’s event, lowriding is not going away.

“I think they’ll carry it on,” said Sylvia Bonilla, 53, who began cruising in lowriders when she was a teenager in San Jose. “My grandkids, my nieces and nephews, they all really like it.”

Contact Matt O’Brien at 408-920-5011. Follow him at Twitter.com/mattoyeah.