There was nothing astonishing about the idea. Two years ago, Georgena Terry, then a 34-year-old M.B.A. whose career path might charitably be described as eclectic, decided to start building bicycles. If that doesn't sound terribly exciting, there is a reason.

It wasn't.

Oh, sure, she'd specialize in high-priced women's bikes, carving out a niche just as they taught her at The Wharton School of Business. But the $1.3-billion bicycle industry didn't tremble at the thought of the diminutive Terry picking up a wrench. True, she might have an interesting twist: her bikes would have a shorter top tube and some would have a slightly smaller front wheel that could provide a more comfortable ride to women cyclists who put in 30, 40, or 50 miles at a clip -- but who rides that far? Most folks -- women or otherwise -- just use their bikes to pedal down to the Dairy Queen or tool around the neighborhood on Sunday afternoons. Besides, if it turned out she had something, the industry could always wheel out a knockoff. Her design wasn't patented, and with the exception of the frame, which Terry makes herself, all her components are bought off the shelf.

So when Terry set up shop in a crumbling industrial park in E. Rochester, N.Y., no one noticed. But they are noticing now. In 1985, Terry Precision Bicycles for Women Inc. sold 20 bikes. Last year it shipped 1,300, and this year it should sell 5,000 more, pushing revenues from both sales and licensing to about $1.8 million.

Suddenly, her banker is more friendly, the bicycle magazines are calling to ask what she thinks about this or that, and oh, yes, the folks at Schwinn Bicycle Co. -- the makers of the first bike her parents bought her 25 years ago -- have suggested she stop by whenever she's in town. Says Terry: "It feels just great. It is a wonderful sense of independence."

It took a while to get there. Growing up in Montgomery, Ala., Terry didn't fit in. She loved science, math, and taking things apart -- her parents still have the remains of watches she never did manage to fix -- but a generation ago only boys were encouraged to pursue these things. So she majored in theater arts in college, "although I gravitated toward the technical end -- stage manager, lighting, that sort of thing."

There wasn't much demand for stage managers, so she went on to Wharton, and then ambled off to PPG Industries Inc. as a financial analyst "like I was supposed to. But I hated it. All I did was push numbers around." So she moved over to Merrill Lynch, Pierce, Fenner & Smith as a stockbroker. That was "boring." Concerned she'd never find a job she liked, Terry took an aptitude test that showed she'd make a terrific engineer. Two years later, she had a science degree from Carnegie-Mellon University and a job at Xerox Corp., in Rochester, N.Y. Two years after that, she was miserable again.

"I finally understood I don't like working for other people," says Terry. "I like to be in control. I hate flying, because someone else is the pilot. On dates, I like to bring my own car."

So she simply stopped working for other people. "I headed off to my basement with my blowtorch and started making bicycle frames."

Excuse us. You went to your basement with what?

Maybe, Terry concedes, a little background would help.

While working at Xerox, she made friends with lots of people who rode bikes. And Terry, who had stopped bicycling once she got her driver's license, found she liked taking long rides with them. Normally, her physical activity is limited. Terry contracted polio as a child and she needs a crutch after walking long distances, but she could ride bikes forever. And she could also take them apart.

She spent a lot of time doing just that, trying to find a comfortable riding position. "The standard bicycle -- even a woman's bike -- is designed for a man. To fit women, who have longer legs and shorter torsos, bike shops shove the seat forward and tilt the handlebars back." That didn't help the five-foot-two, 98-pound Terry. She began wondering if shortening the frame would improve things. So she went down to the basement with the blowtorch -- "a friend showed me how to use it so I wouldn't kill myself" -- and came back up with a bike that had a smaller frame.

Friends saw it, borrowed it, and asked if she'd make frames for them. Terry took a three-month leave from Xerox, and two years later she was still turning out frames and making a living -- sort of.

"Then yuppiedom hit and I got tired of just getting by." It was time to start a company. Bicycling was undergoing a mini-boom and she knew how to make frames, so why not make the whole bike? Seventy percent of all new riders are women, so she'd specialize in women's bikes. She looked at the specifications of the 30 frames she had made for women -- "the data base wasn't all that large, but you have to start somewhere" -- and decided on four sizes.

In August 1985, she hauled seven or eight of her bikes to the New England Area Rally, in Amherst, Mass. "I figured we'd do either very well or very badly. There'd be no middle ground. Women would either go, 'who cares,' or love it." She wouldn't know until she got her first customer. "She was a woman from Ohio in her early forties who had come with her family. She started talking to me Friday night as I set up the exhibit. She came back Saturday, took a bike for a test ride, and bought it [for $775]. We sold three more than weekend and took orders for four more. I have never been more excited in my life. While I was building the bikes, I had never really been sure this would lead to a business. Now, I was convinced."

To her credit, she then moved deliberately. Her major innovation was the frame, so she concentrated on that, and didn't set out to reinvent the (bicycle) wheel or anything else.

Her marketing plan was equally careful. As word spread, people would call up and ask to buy a bike. "We were thrilled, but always asked the name of their local bicycle shop. We'd then call the shop, and say, 'Congratulations, you just sold a Terry bike." Retailers, which found themselves making a quick couple of hundred dollars just for answering the phone, usually were intrigued enough to ask for a couple of more bikes, and that is how Terry put together a dealer network.

With virtually no money for advertising -- indeed, her entire operation is capitalized at $600,000, half bank loans, half from private investors -- Terry concentrated on promotion. She hired a Manhattan public-relations agency that was quick to position her as a female David taking on bicycling's Goliaths.

The approach paid off. The bicycle press discovered Terry. "This is a high-performance machine for serious training, racing and long-distance fitness rides," said Bicycling magazine. Wrote Bicycle Rider: "If you like the finer things in life . . . you'll appreciate a Terry bicycle."

That got customers into the stores, and bikes out the door. "They're selling because ladies feel they fit comfortably on these bikes," says Gretchen Nelson, a co-owner of the Bicycle Exchange, a six-store chain in Virginia. "And they like the fact that a woman designed the bikes."

Terry's professional approach stands out in the industry. Retailers describe high-end bicycling as little more than a cottage industry, filled with scores of tiny manufacturers that can take months to fill orders and are often unresponsive to both customers and shop owners. Terry, who ships on time, courts retailers, and answers questions from customers, quickly became well known and a favorite.

But even as the marketing plan got her up and pedaling, Terry was moving to forestall competition. Recognizing that the high price would scare off many customers, she almost immediately started to segment. Terry now sells two models made in her E. Rochester plant that retail at $910 and $1,560. To preempt the foreign competition that she knew would come, she signed two Asian companies to build a version of her bike that retails for $570 and approved a licensing deal that will retail a yet more basic version of her bicycle for $319.

The strategy has worked so far. Although there are now six companies -- including Fuji America -- marketing bicycles to women, Terry is holding her own. She hopes to be profitable this year. "The other bikes just aren't as good," says Chris Smith, co-owner of City Cycle, in San Francisco, which specializes in high-priced and custom bikes. "Women can tell the difference on a ride around the block." Says Derry Velardi, an employee of a management-consulting firm, who recently bought a Terry bike: "My feet reach the pedals more comfortably, and it is easier to reach the hand brakes. You feel more in control on one of her bikes."

That is, of course exactly what Terry wants to hear. But continued success is far from ensured. Over time, her competitors can be expected to improve their designs, and should the market grow, major companies can be expected to enter. "She makes an excellent product," says Mike Bevis, vice-president of marketing for Raleigh Cycle Co., a division of Huffy Corp., the world's largest bicycle producer. "The concept is good, and we are always looking at what our competitors are doing. You wouldn't have to limit yourself to women. Shorter men and kids in their teens could use this type of bike."

At some point, Terry may have to think about selling out or joining forces with a bigger company to survive. But that is still a ways off. For now, "this is wonderful."