Ms. Birk now helps run a consulting firm, Alta Planning and Design, which advises other cities on how to become more bicycle-friendly. In a report for the City of Portland last year, the firm estimated that 600 to 800 people worked in the cycling industry in some form. A decade earlier, Ms. Birk said in an interview, the number would have been more like 200 and made up almost entirely of employees at retail bike stores.

Now, Ms. Birk said, the city is nurturing the cycling industry, and there are about 125 bike-related businesses in Portland, including companies that make bike racks, high-end components for racing bikes and aluminum for bikes mass-produced elsewhere. There are small operations that make cycling hats out of recycled fabric. Track, road and cyclo-cross races are held year-round, and state tourism groups promote cycling packages. There is Ms. Birk’s firm, which had two employees in Portland in 1999 and now has 14. There are nonprofit advocacy groups and Web sites, including www.bikeportland.org, that are devoted to cycling issues and events in Portland.

And then there is the growing, high-end handmade bike industry, which was made up of just one or two businesses a decade ago but now has more than 10. The Portland Development Commission is working with a handful of the bike builders to improve their business and accounting skills and help them network with one another.

Image Now, business owners like Tony Pereira, a bike builder, are part of the citys growing cycling industry. Credit... Stuart Isett for The New York Times

This month, the city will be the host of a trade show featuring bike builders from Oregon, which locals say has more makers than any other state. And early next year, the North American Handmade Bicycle Show will bring its fourth annual event to Portland for the first time. It is expected to be the largest national show so far.

Sam Adams, a city commissioner in charge of transportation, joined development officials to help lure the show to Portland. It seemed a natural fit. The city regularly ranks at the top of Bicycling Magazine’s list of the best cycling cities and has the nation’s highest percentage of workers who commute by bike, about 3.5 percent, according to the Census Bureau. Drivers here are largely respectful of riders, and some businesses give up parking spaces to make way for bike racks.

“Our intentions are to be as sustainable a city as possible,” Mr. Adams said. “That means socially, that means environmentally and that means economically. The bike is great on all three of those factors. You just can’t get a better transportation return on your investment than you get with promoting bicycling.”