Reinventing The Wheel

By Linda Williams

When it comes to planet-friendly modes of transportation, it is hard to beat a bicycle. Biking uses no fossil fuels, does not pollute the atmosphere and is a great form of exercise for this fitness-crazed era. But in the age of high tech, bicycles have long seemed old-fashioned, a classical conveyance stuck with a century-old design: two equal-size wheels, a welded steel frame, manual gear shifting, pedals and a chain. While cars have loaded up with electronic gadgetry, bicycles have watched the wheels of progress roll by.

Until now. Computer-aided design and aerospace technology have helped create a new breed of bicycles that make riding safer, easier and a lot more fun. Originally created for Olympic cyclists and now available to recreational riders, these faster, lighter vehicles incorporate such features as composite- fiber frames, three-spoke wheels, hydraulic brakes and automatic gearshifts. High-tech models can run well over $1,000 in the U.S., but the price should drop as production increases. A survey of how bikes are changing:

FRAMES. Whether carrying Greg LeMond in a Tour de France alpine climb or a suburban parent with a child in tow, bicycle frames undergo incredible stress, especially where the hollow tubular pieces are joined. For decades, engineers struggled to strengthen frames while making them lighter. That task seemed impossible until manufacturers turned to materials used for jet fighters and missiles. Frames constructed of aluminum, titanium, carbon fiber and various metal combinations have proved to be stronger, stiffer, more shock absorbent and lighter than steel ones. The popular Kestrel frames from Cycle Composites, based in Watsonville, Calif., are made of molded carbon fiber. One-piece and aerodynamically designed, they are stronger and up to 1 kg lighter than premium steel frames.

WHEELS. Modern fibers are also making a difference in bicycle wheels, which traditionally feature dozens of thin metal spokes within a pliable rim. While multispoked wheels minimize wind resistance, they are easily bent out of shape. In the mid-'80s, solid "disk" wheels made of Kevlar improved matters but were somewhat hard to control in crosswinds. A solution came early this year from Specialized Bicycle Components of Morgan Hill, Calif.: a three-spoke wheel developed with Du Pont. Specialized's wheel, a composite of carbon fiber, epoxy resin, Kevlar and aluminum, has an air-foil shape, and was designed with a Cray supercomputer. Tests proved the wheels are faster and more durable than traditional ones.

BRAKES. Standard brakes work much like the ones Italy's Tullio Campagnolo designed 40 years ago. To slow a bike, the rider squeezes handgrips, which are attached to cables that pull on caliper arms. The arms, in turn, clamp down on the wheel rims with rubber pads. The system is simple but doesn't always work, especially with heavy loads or on wet roads. After failed brakes sent him into a tree 20 years ago, William Mathauser, an aeronautical engineer from Anacortes, Wash., set out to improve the system. His hydraulic brake has just gone into full production.

Borrowing the concept from automobiles, the Mathauser Hydraulic Bellowphragm replaces regular brake cables with sealed, flexible tubes that contain hydraulic fluid. When the rider lightly squeezes the handles, a plunger pushes a silicone fluid through the tubes, causing the traditional caliper arms to close. "I designed these mostly for women and children," says Mathauser, 68. "Girls don't have the grip these macho guys have."

SHIFTING SYSTEMS. Changing gears on a ten-speed can be difficult and dangerous. Riders have to look away from the road to see and adjust the shift levers. If a cyclist tries to change gears while standing up to climb a hill, the chain -- and rider -- can slip. "Gear fear" is the main reason why "so many of the ten-speeds that were bought in the cycling boom in the '70s are hanging in garages," says Fred Zahradnik, technical editor of Bicycling magazine. But with new index shifting systems from companies like Shimano of Irvine, Calif., he explains, "you just push the button, hear it click, and you're in gear." Shimano's system uses special teeth and ramps to move the chain smoothly between gears.

CYCLE COMPUTERS. Tiny, handlebar-mounted computers coveted by racers have great appeal to leisure-time cyclists too. Firms like Avocet of Menlo Park, Calif., market a variety of "cyclometers" that measure and record speed, distance and even altitude. Whether gearing up for a race or trying to lose weight, cyclists always like to know their vital statistics.

While bicycles are racing into the computer age, many changes still lie ahead. The bike of the future will probably borrow more materials from the aerospace industry, have a more comfortable, ergonomic shape and employ brakes and gearshifts that are increasingly easy to use. But a few things will likely | remain constant: handlebars, pedals, a chain and two wheels.