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By Matt Pacocha
On the eve of the 25th annual Interbike trade show, set to kickoff in Las Vegas, Nevada, this week, Cannondale got a bit of a jump on the competition and formally released its new Rush Carbon bicycle at a company event held over the weekend at Brian Head, Utah.
The new bike is the evolution of the aluminum Rush introduced last year in Park City. The Rush platform, with 110 millimeters of travel front and rear, is specifically built for the needs of the long haul racer. All aspects of the bike are designed for ultra-endurance racing, though Christoph Sauser demonstrated the aluminum bike’s abilities in a decidedly shorter and faster event, taking second at the World Cup Fort William, Scotland in 2005, his final race as a Cannondale-sponsored rider. The carbon version of the Rush brings two expected benefits to the design, a decrease in weight and an increase in front-end stiffness.
The 2007 model year marks 15 years of system integration by the American manufacturer. “System integration” refers to Cannondale’s holistic approach to building bikes as a complete package. As manufacturers push bicycle weights to the limits, system integration becomes a more common solution within the industry. Cannondale’s first integrated product was the Headshock suspension fork, which made its debut in 1992.
For 2007, the Rush Carbon has integrated the crank, bottom bracket, fork, front hub, stem and headset. Despite its benefits, integration can also lead to inconvenience and sometimes incompatibility. The new Si stem is built as one-piece with the fork’s steerer tube (Cannondale calls it a quill) therefore changing a stem means changing the entire steerer. Fortunately, that task is relatively straight-forward on a bike featuring Cannondale’s Lefty single-leg forks. There is a weight advantage in taking that approach. The new 3-D forged stem weighs 240 grams and knocks more than 100 grams from the previous two-piece system. Each Cannondale dealer will receive a fitting system containing all nine stem sizes packed in a smart looking foam lined suitcase.
The Rush Carbon comes equipped with the new 2.7-pound Lefty Speed SL fork that offers a full 110mm of travel. The SL offers with a lockout as well as size-specific compression valving and a negative spring to better match its rider. The Lefty Speed SL slides on 88 needle bearings as opposed to bushings. Cannondale claims that this fork is unmatched in torsional stiffness in this weight category. As an added bonus, the Mavic CrossMax SLR Lefty specific front wheel is 50 grams lighter than the standard version.
Cannondale engineers identified five criteria that they felt defined the bike’s marathon pedigree: lightweight, suspension performance, handling, efficiency and comfort.
The carbon fiber monocoque front triangle is 300 grams lighter than its aluminum counterpart. The monocoque molding process allows for its unique shape and for the shock mount and pivot to be molded directly into the frame. The massive head tube junctions are designed to help the bike track precisely through corners.
Cannondale engineers are quick to point out that regardless of suspension design, the ideal wheel path is up and back, which the Rush’s single pivot design provides. Cannondale engineers claim that a unique combination of a regressive leverage ratio frame design and progressive shock, gives a Rush rider better suspension performance throughout its travel than if both were progressive.
With the final design, Cannondale engineers felt they have found a bike that performs well on all fronts while providing benefits unique to a single pivot design. A single pivot bike’s maintenance is arguably simpler and quicker, not to mention cheaper to manufacture. Cannondale also claims that the weight saved using one pivot can be used elsewhere to build a stronger more durable frame.
The Rush is unique in its geometry. It has short chainstays and a slack head tube, these are attributes meant to make the bike stable yet maneuverable. Engineers kept in mind the bike’s mission, as an endurance racer, and assumed that there will be times when the rider is on “auto-pilot” on a night lap at two am in a 24-hour race and the bike needs to be as forgiving as possible. The Rush also has a relatively low bottom bracket, a feature that might just catch an unsuspecting new rider off guard.
For 2007, the Rush Carbon will come in three models, each of which will be offered in small, medium, large and extra large. The Rush Carbon 2 is the entry model at $4500. It will come with a Lefty DLR2 fork and Shimano XT level components. It weighs 25.5 pounds in a medium. The Rush Carbon 1 comes with the new Lefty Speed SL, Mavic Crossmax SLR wheels and a Shimano XTR group. It costs $6000 and weighs 24.07 pounds. The flagship Rush Carbon Team comes with SRAM’s X.0 group and Avid Juicy Ultimate brakes, it costs $6500 and weighs 23.7 pounds.