HOLLYWOOD — The shop marks its fortieth spring this month the way it has marked most of them, with a repair stand out on the sidewalk and a hand-lettered sign offering to teach anyone who asks how to fix a flat for free.

The bicycle shop, tucked on a side street off Sunset in a bay barely wide enough for two repair stands, opened in 1984 and has watched at least three larger competitors open nearby with more inventory and lower prices, and then close. Its owner, Gene Halvorsen, 63, is not sure he has ever fully understood why the small shop survived them, though he has a theory, and the theory has to do with Thursday nights.

For roughly thirty years the shop has hosted a Thursday-evening group ride that leaves from the sidewalk out front, loops through the flats below the hills, and returns for whatever repairs the ride turned up. Halvorsen has never charged for it. He estimates it has cost him a small fortune in unpaid Thursday hours and earned him something a discount could not, which is a few hundred regular customers who think of the shop as theirs.

“People don’t buy a bike from you because you’re cheap. If they want cheap, the internet already won that,” he said, wiping grease from a cassette. “They buy from the guy who taught their kid to ride and pumped their tires for a decade for nothing. That’s not strategy. It’s just the only way I ever knew how to run it.”

The business itself is unromantic. Roughly two-thirds of the revenue comes from repair, not sales, and the repair side has held up better than the retail side as online sellers took the easy transactions. The rise of electric bikes has cut both ways: they bring in higher-value service work, and they require training and tools the shop had to buy on credit to keep up.

Renata Villanueva, 34, has ridden with the Thursday group since she moved to the neighborhood without a car six years ago. “I walked in knowing nothing and asked the dumbest possible questions,” she said. “Nobody made me feel dumb. Now I do most of my own work and I still buy every part here, out of something like loyalty. He built that on purpose, whether he admits it or not.”

Halvorsen admits the math is tighter than it used to be. Rent on the small bay has climbed with everything else in the neighborhood, and he has had to raise labor rates twice in three years, which he hates. He has no succession plan and no children in the trade, and when pressed on what happens when he stops, he changed the subject to a wheel he was truing.

For the anniversary he is planning nothing larger than a slightly longer Thursday ride and a cooler of drinks on the sidewalk. Forty years in, he said, the shop does not need a party so much as it needs the tires to keep going soft, and around here they always do.