High-Tech Bicycle Toys at Interbike
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High-Tech Bicycle Toys at Interbike
Material Science
It's often been said that if the auto industry made advances as rapidly as the computer industry did, we'd all be driving safe and fast flying cars that cost ten dollars and got a thousand miles per gallon. There's no Moore's Law for bicycle technology, but it's safe to say that if the auto industry mirrored that, we'd have faster, safer cars that got maybe a few hundred miles per gallon.
Take the case of carbon fiber. In cars, you'll see it only in Formula 1 racers or in expensive aftermarket products. And carbon fiber is certainly used by professional bike racers—Lance Armstrong won his Tours de France on a carbon-fiber Trek—but mere mortals can now buy entry-level bikes with the wonder material from large manufacturers such as Trek, Specialized and Giant, and these sub-$1,000 bikes are more advanced than the top prototypes of only a few years ago.
The Case of Ibis Bicycles
Ibis Bicycles makes a case in point. The company was a stalwart of the Northern California road and mountain biking scene in the 1990s with a range of titanium-framed bikes. The owner, Scot Nicol, sold Ibis in 2000 but used the Interbike venue to come back with a new line of carbon-fiber road and mountain frames.
Both bikes, the Silk Carbon road bike and the dual-suspension Mojo Carbon, were designed with the help of Roxy Lo, who previously had worked on product design for companies such as Pottery Barn. She used Adobe Illustrator to create the preliminary designs for the flowing, raised lines of the frames, based around certain "fixed points" (such as where the wheels go), to give the bikes a distinctive and more-than-functional look. Then she moved into Ashlar-Vellum's Graphite 2D drafting software to finalize the design. Then she handed it off to Ibis engineers who used PTC's Pro/ENGINEER Wildfire to make a 3D model.
Though this resulted in extra material being used for the sake of looks, Ibis claims that a 58cm Silk Carbon frame comes in at 950 grams.
All carbon-fiber frames are made from a composite of carbon-fiber filaments bonded into a matrix by resin. All filaments have properties of tensile strength and modulus (stiffness); a filament of a certain tensile strength can be soft, medium, or very stiff. Most filaments used today have a tensile strength of around 500 ksi (thousands of pounds per square inch). This represents an increase over carbon fibers used a decade or so ago, making for less delicate frames.
But advances in resin have also played a big part. In recent years, resins with a lower viscosity have come onto the market, which allows for a lower volume of resin to be used, which means a higher concentration of carbon fibers, which means more strength. As a result, frame builders can use less material to make a lighter, stiffer, yet stronger frame—all good things.
Though some builders make carbon bikes from pre-made tubes and bond them to joints, called lugs, as traditional steel-based frames and early carbon-fiber frames were made, the Ibis frames are of monocoque construction. This means that Ibis takes prepreg (sheets of carbon fiber pre-impregnated with resin) which are cut and worked in climate-controlled clean rooms to keep the resin from curing.
The sheets are made of unidirectional filaments aligned at varying degrees, ranging from -45 degrees to 0 degrees to +45 degrees. The sheets are strongest along the direction of the fiber; different sheets are laid up over each other to reinforce the resulting frame along major stress axes, which have been identified using Finite Element Analysis (FEA).
This is done on a silicone form, which is removed once the carbon-fiber sheets have been laid. The result is put into a steel mold and air bladders are inserted into the hollow tubes. The whole thing is "cooked" at 220 degrees Farenheit to cure the resin. After that, the frame is removed, cooled and hand-finished. The process is a long and costly one, which makes the Silk Carbon's price of $1,399 (frame only, no fork or components) seem relatively competitive in the top-of-the-line bike market.
Other notable carbon-fiber-based bikes at the show included Wilier and, believe it or not, Cadillac.
This does not mean that builders using titanium, another high-end material, have stood still. In recent years many builders have discovered new ways to work with harder alloys of the material, finding ways to lighten and shape, for example, 6/4 titanium (and alloy with 6 percent aluminum, 4 percent vanadium), which previously was reputed to be a tool-breaker.
And some builders, such as Titus Cycles, have found ways to merge the best of both worlds. Frame builders such as Independent Fabrications, Seven and Serotta have made frames that combined carbon-fiber tubes with titanium lugs, but Titus showed its Exogrid frame, which uses cut-out titanium tubes with carbon-fiber inserts. The entire tube is then molded at high temperatures and pressures.
Titus claimed that this combination makes for a frame that's both lighter and stiffer in critical directions than plain titanium. It certainly could be the frame for someone who wants something different.
A computer that just measures speed and distance—and even heart rate—is old hat to the serious cyclist: It's all about power output these days. Measuring power is billed as the most accurate way to determine training and racing effort; heart rate is too dependent on factors such as fatigue, and it doesn't take into account body mass, wind, and other conditions.
At Interbike, a variety of manufacturers were showing off power-based training systems. Cycleops had its PowerTap, a wheel hub with a built-in power measurement system. The PowerTap sends data to a handlebar-mounted computer, and can also download data to a desktop computer equipped with the included CycleOps PowerLink software, which provides tools for visually analyzing power output in watts over time.
However, the PowerTap solution requires a rider to use a wheel built around the PowerTap hub. Many bike riders and racers use separate sets of wheels for training and racing; equipping multiple wheels with PowerTap hubs (which start at $699.99 for the base model) is an expensive proposition.
Though the Ergomo power measurement device, from the German company of the same name, costs over a thousand dollars, it doesn't require any extra expense if you want to switch wheels. This is because the Ergomo monitors power output by measuring torsion in the bottom bracket—the central spindle around which the cranks turn. As a rider pedals, the bottom bracket axle twists almost imperceptibly; the Ergomo measures this through an optical system and reports the data to its own handlebar-mounted computer. This, said the manufacturer, keeps the weight penalty of using a power meter down to only 80g and allows the use of any wheels and crankset.
As with the PowerTap, the Ergomo can download its stored data to a PC, which can then be used for training analysis. In addition, the ergoRacer software can upload your data to a Web page, allowing remote access to your data by your coach.
A Cannondale equipped with SRM's power-measuring crankset!
Though the company wasn't exhibiting at Interbike, the German company SRM's power measuring product was visible on bikes from manufacturers such as Cannondale, which will be selling stock road bikes in 2006 with the SRM Training System built in.
One of the first power meters used by pros, the SRM replaces the entire crankset with its own, which includes a power measuring unit that uses strain gauge strips to detect deflection during pedaling. As with the other systems, the data gathered is not only shown on the handlebar-mounted computer during rides but can be downloaded to a PC.
However, what to do when you need the data now, and the rider is still out on the road? That's where the true tech geeks came in.
In the most recent Tour de France, SRM equipped a number of riders not only with the power-measuring cranks but also with GPRS modems developed by T-Mobile and SRM. This allowed monitoring of the riders' power output, heart rate, cadence, speed and time on the bike for up to 1000 meters. These data were not only used by team managers and coaches, but were also included in live coverage broadcasts on German television.
And for those who don't want to venture out in to the world just for a bike ride, there were alternatives.
CycleOps showed off a stationary trainer that allowed users to race on a virtual track against phantom competitors. Users could save their top races and compare notes with other owners of the same product.
http://www.extremetech.com/article2/0,1697...,1868738,00.asp
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