The bicycles ridden by the racers in the Tour de France bear as much resemblance to your childhood Schwinn as a Piper Cub does to an F-16: Only the basics are the same.
But the high-tech, multithousand-dollar bikes zipping through the French countryside are based on a 125-year-old design that remains stubbornly resilient - a simple, profound piece of engineering that continues to have a hold on the human spirit.
"It is one of those inventions that stirs passions," says Roger White, a specialist in transportation history at the Smithsonian Institution.
The basic blueprint belies such devotion - two triangles of tubing and two wheels, a front one that steers and a back one driven by a chain connected to the pedals.
It was called the safety bike when in first appeared in the 1880s, replacing the high-wheelers - with huge front wheels and tiny back wheels - that had made the bicycle the province of athletic young men. The new version brought the freedom of personal transportation to masses, including women. That design remains the most efficient method ever invented to convert human energy into motion. Those seeking to make it even more efficient now work on the edges of technological innovation.
The Schwinn of 40 years ago was made of thick steel tubing. It tipped the scales at close to 30 pounds. If it had any gears, it probably had three. If it was very fancy, it was a 10-speed - two gears in the front and five gears on the back wheel.
Though plenty of bikes are still made of steel, none of those in the Tour de France is. Composites of carbon fiber along with aluminum and titanium dominate. Bicycle manufacturers are out there with Formula One race teams, pushing the technological envelope of these materials.
"It is well-known that automotive manufacturers come to us to fabricate composite parts for them," says Steve Westover, promotions manager of bicycle manufacturer Giant, which builds carbon fiber from scratch for the bikes of the T Mobile team of Jan Ullrich, one of the top rivals of American Lance Armstrong. Giant and Trek - which makes the bikes for Armstrong's U.S. Postal Service team - were pioneers of carbon fiber bikes.
Most of the current crop of bikes in the Tour de France weigh just more than 15 pounds. Constant tinkering with the design and composition of the frames is aimed at giving the bike the proper balance between resilience - for comfort - and stiffness - so it will efficiently translate the power of muscles into forward motion.
The chains of these bikes still go around two gears in the front, but there are now 10 on the rear wheel, giving the riders 20 gears to choose from.
And the price is a lot more than you paid for that Schwinn. When Giant puts the bike that T Mobile is riding on the market this fall, it will cost around $5,000. Amateur racers regularly pay $3,000 and up.
The past decade has seen an explosion of technological innovation in bicycle manufacturing. Before that, it was a rather tradition-bound world dominated by small European companies that often viewed improvements with suspicion.
Now, though the sport of bicycle racing remains primarily a European preoccupation, many of the top riders are on non-European bicycles. Teams in the tour ride bikes from U.S.-based Specialized, Cannondale and Trek, Canada's Cervelo and Taiwan-based Giant. This would have been unthinkable a decade ago - Westover says getting non-European bikes in the Tour de France was like breaking up the Mafia - but companies like these led the way in pushing the envelope of the bicycles' possibilities.
The technological cutting edge is where bicycles started. "In the 1880s and '90s, bicycles were to that generation what the PC and notebook computers are to this generation," says bicycle historian Peter Joffre Nye. "They attracted the best and brightest."
"The bicycle put technology into the hands of individuals," White says. Many of them tried to improve the breed. The result was an outpouring of creativity.
Nye notes that in the last quarter of the 19th century, fully one-third of the patents granted in the United States were related to the bicycle.
"The Patent Office created two branches, one for bicycle-related stuff and one for nonbicycle stuff," he says.
In that era, virtually every town in America had at least one bicycle racing track - a banked velodrome. "Bike racing was a cutting-edge sport," says Nye, author of Hearts of Lions, a history of bicycle racing in the United States.
Those attracted to it were looking for speed. It did not take long to figure out that vehicles propelled by the new small internal combustion engines would go faster than human-powered machines. The first motorcycles were basically bicycles with one of those engines attached.
Nye is at work on a biography of Albert Champion who came from France in 1899 to race bicycles for a Massachusetts company. It was the same year another French bike racer, Louis Chevrolet, crossed the Atlantic.
Both turned to motorized forms of racing. Champion founded the spark plug company that still bears his name and another company using his initials that lived on as part of AC Delco. Chevrolet became a consulting engineer to the founder of General Motors and left his name on one of its most popular cars.
Carl Fisher, who founded the Indianapolis 500, started out racing bicycles, as did many other automotive pioneers. Nye says that much of the technology essential to the development of the automobile - pneumatic tires, drum brakes, rack-and-pinion steering, the driveshaft, ball bearings - was developed for bicycles and adult tricycles.
Others, most notably the Wright brothers, took their interest in bicycles and transferred it to airplanes.
The rise of the automobile followed the same path as the bicycle. Both started as pastimes of the wealthy and made their way to all economic classes. Not surprisingly, interest in the bicycle declined as the automobile took over. But it did not disappear.
"Their popularity waxed and waned," says White. "In the 1930s, bicycles made a comeback as a children's market. After World War II, you see some adult bicycle buying happening again. Then you have them coming back with the health kick of the '60s, the concern for the environment in the '70s, and it's been sustained ever since."
Interest in bicycle racing also declined with the rise of the automobile. The sport was virtually nonexistent in the United States in the years after World War II, but its popularity was growing in Europe, where racers like Italy's Fausto Coppi provided the devastated continent with new heroes.
It still is a blue-collar sport in Europe. Crowds cheered those who made what was the basic form of transportation into an instrument of sublime speed. Auto racing there was the province of the wealthy.
That was not the case in the postwar United States, where the automobile was the basic form of transportation. Auto racing developed a blue-collar following parallel to that of bike racing in Europe.
But in 1986 with Greg Lemond becoming the first American to win the Tour de France (he also won in 1989 and 1990) and now with Armstrong going for his sixth straight victory, U.S. interest in bicycle racing is rising.
That has helped push the American manufacturers into developing some of the world's top bikes. But much of their innovation can be attributed to the rise of the triathlon in this country. Those athletes, who often came from swimming or running backgrounds, sought new ways to make bicycles faster.
"They were some of the first people to be open to using new and different products," Giant's Westover says. When Lemond won the Tour de France in 1989, he used aerodynamic handlebars - then called tri-bars because they were developed for triathlons - and a streamlined helmet in the crucial final time trial. They were controversial at the time, but today all riders in the race use descendents of those devices, now thoroughly tested in wind tunnels.
Beneath that technology, though, they are still riding the same device that captivated the world 125 years ago and has never let go.
"It's almost like an extended fad that disappeared and reappeared but never completely went away," White says. "Clearly there is an emotional side to it."