Jeff Hansen is part banker, part cave man. He likes his bacon with a side of sausage and does household repairs with wire and duct tape.

He loves Dr. Dre and rocks out to Led Zeppelin.

But nothing makes him crank up the volume like Taylor Swift.

“The only time I turn down Taylor Swift is when the police come and turn it down for me,” said Hansen, 26, who is from Syracuse, Utah. “Seriously, why would you turn down the sounds of heaven?”

Hansen is among the Surprising Swifties — rugged individuals who find themselves powerless to shake it off. They drive forklifts, swing axes, power diesel trucks and catch touchdown passes on NFL Sundays.

Some of these burly woodsmen will be singing along with every word from the glittery pop sensation when Swift’s “1989” tour arrives for sold-out shows at Levi’s Stadium this Friday and Saturday.

It won’t be the first time her voice echoes around the venue. Last week in the 49ers locker room, that sweaty bastion of American masculinity, Swift’s music set off a fierce debate among players.

Wide receiver Torrey Smith, a leading advocate for the pro-Swift faction, tried to settle things by marching over to the sound system, connecting “Bad Blood” from his personal playlist and daring teammates not to bounce along.

It was like a slumber party broke out.

“All of a sudden they were in there were nodding their heads saying, ‘I didn’t know this was Taylor Swift!’ ” Smith said. “Yeah, it is. Get with the program.”

Smith, in his fifth NFL season, was reminded that not every tough guy is so willing to publicly declare himself a Swifty.

“That’s what separates the men from the boys,” he sniffed. “You gotta be proud.”

Indeed, Swift’s fan base goes beyond the hella millions of adolescent girls who helped her “1989” album sell more copies in its opening week than any album in the previous 12 years. The songwriter behind irresistibly catchy tunes has shown fans incredible things: seven Grammy Awards, 11 Country Music Association Awards and more than 130 million single downloads.

Still, there are closeted Swifties. One Bay Area athlete last week described himself as a “huge” fan of her music but quickly retreated when he saw a notebook come out. The player backpedaled so fast it looked like the Tour de France in reverse.

Reporter: “But there’s no shame in it.”

Player: “There’s some shame in it.”

Others ruffians, however, are like Swift’s characters in the “New Romantics” — they sing it proudly.

“You can’t Swift Shame me,” said Nate Morgan, 37, a former truck scale weighmaster from Lafayette. “Totally out. Proud. Give me an opportunity to make it uncomfortable for Facebook friends, family and co-workers, and I’m a happy man. Because you know all of these people love her, too.”

“My teenagers hate it when I like the songs I do, but I do not care,” said Adrian Jenkins, a 41-year-old administrative assistant. “She is awesome.”

Adam Sturgeon, 34, works as a sports video editor for Yahoo. He’ll be there at Levi’s Stadium, hoping for a repeat of what happened during his previous visit to a Swift concert. “She came out onto the part of the stage that extended out to the crowd, and we got really close to her,” Sturgeon said. “I was screaming like a little girl!”

Thanks to some other prominent tough guys going public with their mad love, it’s becoming increasingly safe for people to talk about Swift — a safe space for their “Blank Space.”

Swift’s muscle-bound fans include actor/wrestler Dwayne “The Rock” Johnson, who announced he was going to sing some “Tay-Tay” before unleashing a dead-on version of “Shake It Off” in a lip sync battle. (The Rock even nailed the schoolgirl giggle).

NBA star Russell Westbrook taped a video of himself singing “Bad Blood” and posted it on Instagram. When Swift responded, Westbrook exploded with six exclamation points and three emoticons — both season-highs.

“If you say you don’t like Taylor Swift, you’re just lying to yourself,” Los Angeles Dodgers ace Clayton Kershaw once told the MLB Network. “If you’re a dude and you think you’re too cool to like her, then, just get over yourself, really.”

Sonny Gray, another ace, also is aboard and has been for years. In an interview last week, the A’s All-Star pitcher said he grew up in the Nashville area, where Swift first became a star, and said her music was “definitely a topic, for sure.”

“It’s catchy,” Gray said. “If it comes on, I’m definitely not going to change it.”

Still, there’s a stigma — “a scarlet letter,” as Swift sings — that keeps some adults from jumping aboard such a sparkly train. “Saturday Night Live” spoofed the phenomenon in a sketch featuring a fake doctor touting “Swiftamine.”

“Medically, speaking, Taylor Swift-onset vertigo occurs when one of her songs comes on, forcing your brain to fight your ears,” the doctor explained. “Your frontal lobe says, ‘Oof. Taylor Swift.’ … But your ears say, ‘Shut up. This is a perfect song.’ “

Not everyone needs the medical intervention. Morgan, the former truck scale operator and forklift driver, has his full-fledged man card. At 6-foot-3, 270 pounds, the bearded father of four was introduced to Swift’s music by his kids in 2008.

Not long ago, he offered to give a co-worker — the equally manly Stu — a ride home. When Morgan turned on the engine, the two were jolted by the sounds of “1989,” still blaring from the morning ride.

It was awkward.

“Stu said, ‘Drove your kids to school today, eh?’ ” Morgan recalled. “I didn’t bat an eyelash. I said, ‘No, man, I’m proud to be a Taylor Swift fan, and you can be, too.’ I turned up the volume and we drove home.”

Stu didn’t say a word.

“But I’m sure he was just taking in the music,” Morgan said.

Hansen, the banker from Utah, is a parent, too. He has a 1-year-old daughter.

“My wife would like me to claim that she’s the reason I listen to T-Swizzle, but that’s simply not true,” he said. “This love is straight from my own heart.”

Surely, that gets him some grief from his bros.

“Yes, but when flak comes I just show off my chest hair and chew on some glass,” Hansen replied.

Scott Brown, 44, wrote a book on masculinity. He co-authored “The Man Code: A Woman’s Guide to Cracking the Tough Guy.” Asked for a few more ruggedness qualifications, Brown added that he took a bereavement day after former Raiders quarterback Kenny Stabler died and that his five favorite restaurants are Irish bars.

His Man Code includes permission to be a Swifty.

“I took my oldest daughter (age 10) to an A’s game, and they played a Taylor Swift song between innings,” said the marketing and communications manager from Carmel Valley. “I stood up and started dancing, and she was trying to get me to stop, which in hindsight I recognize as being Jumbotron gold.

“Sure enough, they put us on the big screen. I thought that was the worst of it, until a friend texted me and said we were on ‘SportsCenter,’ too. So, yes, I’m out.”

Brown said he started listening to Swift because of his two daughters and now describes “Shake It Off” as a “gateway drug” to the rest of the Swift catalog.

These days, he’ll happily unplug his Otis Redding and Wilson Pickett to sing along to lyrics about nice dresses and rosy cheeks. Brown likes the way Swift connects him to his whole family — even if they don’t let him dance.

“As the father of two girls, I appreciate that (Swift) has a sense of responsibility to her audience,” he said. “She seems to know that kids like mine are discovering music that informs their sense of how it’s acceptable to feel.

“Artists like Rihanna and Miley have enough fame for 100 lifetimes, but they’ve given up something in order to be something. You wonder if there’s even a beating heart there anymore. But Taylor seems like she probably sleeps well at night, as she should.”

Cool story, bro.

Contact Daniel Brown at dbrown@mercurynews.com