PROVINCETOWN — At the Bike Shack on Shank Painter Road, the squeal of mechanical parts harmonizes with the squawk of the house parakeets.

“This bike’s been outside,” owner Liz Athineos says, tapping the back wheel of a dark red model with the point of her screwdriver. “You can see it’s covered in dirt.” She carefully slides the cogs away from the frame to wipe away the grime.

Athineos is maniacal about keeping everything in the shop spotless. Mud, she says, can wear down the chain and interfere with gear shifting, and rust can lock a seat or a pair of handlebars in place. She says she gets her regard for cleanliness from her mom.

“I always tell people to oil these,” says Athineos, gesturing to a line of bicycles. “They won’t.” People think it’s OK to ignore that fundamental. “No, it isn’t OK,” she says. According to Athineos, the worst thing cyclists can do is assume their bikes’ problems will fix themselves. “Owners hope. You can’t hope. It’s only a bike.”

Not every mechanical problem is obvious. This year Athineos changed “probably about 40” cassettes — the collections of cogs that sit beside the back wheel of a bicycle. She points to the Provincetown Laundromat across the street from her shop. She has cyclists ride their bikes up that hill where the laundry is to find out if the cassettes are clicking. Hers is the only bike shop in Provincetown that is open year-round.

Athineos got her technical expertise at Mechania, a “hippie-dip” auto repair shop in Boston that rented garages to apprentice mechanics for $1.70 an hour in the early 1970s. In 1976 she and her girlfriend, Pat, opened a women-only repair shop called P&L Auto. “Pat was just there to support,” Athineos says, “but anyone who was around me developed those skills.”

She first came to Provincetown in 1982 when she got a job as a mechanic for what she calls “the phone company.” She stayed with Bell Atlantic and then Verizon for 25 years, moving from that job into management.

Athineos opened the Bike Shack a decade ago with her brother Stephen, who had become a celebrity in the New York City biking community, she says, after leading the 1987 protests against Mayor Ed Koch’s proposed ban on cycling in midtown Manhattan. Steve died of a heart attack in 2015 after only two seasons at the shop, leaving Liz to manage the business by herself.

But Athineos has no problem flying solo. Last year, she knocked down her shop and built a bigger one in its place. The word “shack” doesn’t exactly describe the new building, which is big enough, she jokes, for her to “land a friggin’ helicopter.” There’s an immaculately organized basement and two floors that’s home to her family — Liz’s son, Luke, who releases emo rap under the name Lukejxdy, and her mother, Evangeline, live with her. There’s also more than enough space behind the counter for the shop’s mechanics to do their work — something they could only dream of in the old shop.

Athineos oversaw the construction herself. She got her supervisor’s license in 2022, started pouring the foundation in 2023, and finished the entire project in time for the season this spring.

“When you’re sober you make up for lost time,” she says.

Athineos struggled with alcoholism for much of her youth but has been sober for the last 42 years, she says. She goes to Alcoholics Anonymous meetings in Provincetown nearly every morning — though she missed some during the seven and a half months it took her to rebuild the shop.

Addiction was present even in Athineos’s childhood. She swears that her father, George, who played with the U.S. national soccer team in 1953, could have been in the hall of fame if not for his gambling problem. Liz herself trained as a kayaker for the 1972 Olympics. “I never lost a race,” she says, but couldn’t go through with it because of her drinking.

“I knew for an absolute fact that I didn’t give a crap,” she says, looking back on what she now sees as a wasted youth.

Even though she says she isn’t finished with all the renovations at the shop, another project is already brewing in Athineos’s mind. She’s interested in the white building just next door, which she wants to use to help people with Alzheimer’s. She envisions a place that would provide rides and help with shopping for groceries and setting up doctor’s appointments. There would be a garden in the back.

She says that caring for her mother is what has shaped that vision. Even though the two haven’t always had the best relationship (she says Evangeline once called her “very sick” for being gay), Athineos sees her mother as an important part of who she is.

“She gave me my life back,” she says. It was Evangeline, she says, who brought Liz’s father to Gamblers Anonymous for the first time, and it was Evangeline who first warned Liz about what she calls “the ‘ism.’ ”

Athineos looks up from a bike she’s working on and steps back, taking a moment to marvel at the place she’s built: “I wish I’d done this sooner.”