SHANGHAI, China — For a vivid insight into the clash of old and new in China, follow the bicycle.

Morning rush hour in Beijing and Shanghai used to be rivers of cyclists flowing in a majestic hush down broad bike lanes. Today, many of those lanes have been taken over by cars and buses, their roar and honk drowning out the tinkle of bicycle bells.

Yet despite China's leap into modernity, the bicycle is far from dead — its numbers are growing. For many Chinese, pedal power remains a mainstay — for commuting, sending children to school or making a living.

And getting around the traffic jams.

As the Chinese fall in love with cars, and Westerners fall out of love with them, China is once again a winner. According to the Earth Policy Institute, a Washington-based environmental think tank, of the 130 million bikes manufactured worldwide last year, China made 90 million, and exported two-thirds of them. About nine in 10 bikes bought by Americans are made in China.

In China, the bicycle's enduring role epitomizes the country's wider transitions — from countryside to city, from planned economy to freewheeling capitalism. Multiplying cars may be a sign of affluence, but the bike's staying power is a reminder that most of China's 1.3 billion people have yet to make it into the middle class.

In the shadows of Shanghai's skyscrapers and towering elevated highways, it is bicycle wheels that have enabled migrants like Wang Chunliang to make the great leap from countryside to the big city.

Tan and sturdy, the 30-year-old hauls flowers and garden supplies from an outdoor market to upscale Shanghai homes on a three-wheeled bicycle cart called a "sanlunche" (pronounced san-loon-chuh). That and a little gardening earn him about $300 a month — enough to live on and support his family in rural Anhui, hundreds of miles away.

"Compared with some jobs, this isn't too bad. And it's a decent living," says Wang, shrugging off the perils of traffic and bad weather.

In Shanghai and other cities, pedal-pushing rural migrants can be seen everywhere, delivering goods, gathering waste for recycling or peddling anything from popcorn and pirated DVDs to books and baby rabbits.

TWO WHEELS WITH A PIPE

The millennia-old Middle Kingdom can claim to have invented many things — fireworks, the umbrella, paper and the compass among them — but not the bicycle.

According to Amir Moghaddass Esfehani, a historian at the Technical Institute of Berlin, the Chinese first learned of bicycles from a customs official named Binchun who visited Paris in 1866 and wrote of Parisians riding vehicles made of "two wheels with a pipe in the middle."

Back then, well-heeled Chinese generally got around in rickshaws or sedan chairs, both hauled by manpower. It was only after expatriate Americans and Europeans began cycling around Chinese cities that the fashion took off, Moghaddass writes in "The Bicycle and the Chinese People."

Through the three decades of communist central planning, bicycles were encouraged as transport; buses were crammed and infrequent, taxis virtually unheard of.

Shanghai Forever, Flying Pigeon and Phoenix bicycles were the Chevys and Buicks of those days.

For the Beijing Olympics, the city is offering visitors 50,000 bicycles for rent, but many bike pathways in Beijing and Shanghai have been taken over by right-turn and bus-only lanes. Big offices and hotel buildings generally provide bicycle parking onsite only for employees.

Shanghai's 10 million bikes are banned from many main streets. A trip from Hongqiao, in the western suburbs, to the busy Nanjing Road shopping district is an obstacle course around no-go zones and subway construction projects. The riverside bike paths so familiar in Western cities are nonexistent.

"This is a question of government policy," laments Chen Haiming, who is an engineer and general manager at Shanghai Forever Co., China's biggest bicycle maker. "In Europe they are building bicycle pathways and encouraging people to commute by bicycle. But not here."

All the same, Shanghai's more than 20 million people have few options. The subways and buses can handle only one-quarter of commuting volume. A modest family car costs about $6,000 and licensing it $5,000 — adding up to more than most Shanghai workers make in a year. A scooter sells for about $300.

So by bicycle or scooter they wind their way through rush hour traffic, many wearing cotton masks to filter out exhaust fumes. They weave on and off sidewalks, dismount to squeeze between buses and curbs, slip haphazardly through gridlocked intersections and, sometimes, glide triumphantly past traffic jams.

Later in the day comes a second set of cyclists. Clanging cowbells to be heard above the din of the street, they roam the city hunting for scrap metal or discarded appliances. Some balance TV sets, computer terminals, even refrigerators and mattresses, on the backs of two-wheelers.

Life on wheels can be a cat-and-mouse struggle.

"It's easy to park, and easy to escape when the police come after us," says Wang Dali, a migrant from Anhui province who sells pirated DVDs of movies such as "Kung Fu Panda" and "Sex and the City" off the back of his old Phoenix.

"We aren't allowed to sell in these areas, since it's said to give the city a bad image," said Wang, looking a decade older than his 33 years from a lifetime spent outdoors in the sun and wind.

"Only we poor rural people do this, but we have to, to make a living," he said.

DOZENS OF MODELS

Meanwhile, bike companies have been retooling.

Twenty-two years ago, when Chen was first assigned to work at Shanghai Forever's rusting factory in downtown Shanghai, the company was still only turning out 40-pound heavy-duty bikes built to carry loads and entire families on the crossbar, handlebars and rear carrier.

Today, Forever's Web site displays dozens of models, from high-tech mountain bikes to foldables that can squeeze into a briefcase.

Chen is confident that despite China's enchantment with the automobile, bicycles are here to stay.

"Bicycles can help protect the environment. People need them for exercise," he says. "The bicycle will never be obsolete. No matter how well developed the automobile and aircraft market grows, the bicycle still has its purpose."

Wu Liqiang, manager for the host of a Shanghai TV show, agrees.

He vividly remembers his first bicycle, in the 1970s, a chic black Forever.

"The feeling I had riding that bicycle was amazing. It was just about as cool as driving a Porsche would be now," says Wu, now 50. "Girls were very glad to go out with me because they could sit on the back of my bicycle and enjoy the breeze and sunshine."

He owns a bright-blue VW Polo but hardly ever drives it.

"The traffic's getting worse and worse and you end up wasting hours on the road," Wu says, adding, "The bicycle is still the best vehicle for China."

He commutes to work by bicycle.