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Strength in the featherweight division.
Ridley's engineers set out on a new mission right on the heels of the Helium's release. The goal was to maintain the stiffness and stability of the proven original, while at the same time reducing its overall weight. The result of their efforts is the aptly-titled Helium SL. At around 1050 grams with the fork, the SL frameset rests squarely at the front of the market's low-weight frame offerings. And while most sub-800 gram frames are more akin to wet noodles, the SL is responsive and bred for racing in the mountains. And now, finely tuned with a full Shimano build kit, the Helium SL/Shimano Ultegra Complete Road Bike - 2014 is eager to launch you up the steepest of climbs with ease.
Starting with the weight, the SL sees a 150 gram decrease from the last iteration of the Helium. This was achieved through the use of a more sophisticated carbon selection, this time utilizing a strategic placement of 60, 40, and 30 ton high-modulus carbon fiber. Before the SL, the Helium featured a predominately 30 ton carbon composition. Why is this important? Well, for a refresher, the 'ton' designation in '60 ton' refers to the carbon's ability to withstand 60 tons of pressure per square millimeter. So, basic logic tells us that a stronger carbon fiber requires less carbon to be used — as is the case with the SL. And on top of the carbon, Ridley bonded the carbon with a nano resin this time around. This further reduced weight, and it also increased the strength of the construction.
Not surprisingly, Ridley wasn't done yet. To further reduce weight, Ridley constructed the front triangle of the SL with a monocoque design. This means that the entire front triangle (head tube, down tube, seat tube, and bottom bracket lug) is made in one piece. How does this save weight? Well, with the current SL system, the seatstays, chainstays, and dropouts are bonded to the existing triangle by applying resin and then over-wrapping the bonding points with more carbon fiber. With the SL, this application only occurs once, whereas you can imagine the added weight of repeating this process at every tube juncture of the frame. Furthermore, Ridley shaved grams by giving the SL a slightly smaller head tube dimension than the original Helium, with a 1-1/8 x 1-1/4in tapered design instead of a 1-1/8 x 1-1/2in.
For further weight reduction, the SL also received a new tube shape design. For some background, Ridley's design philosophy is that form needs to follow function. And to Ridley, nothing better demonstrates the harmony between function and form than that of shapes found in nature. Accordingly, the SL takes its design inspiration from the circle. Yes, the circle. Stop and think about it, and you'll realize that nothing provides a stronger construction with less mass than the circle. You've probably seen this on the Helium, only this year, the SL does away with the massive, oversized tubing. Now, the SL features rounded tubing emanating from the seat tube juncture, that slowly becomes box-shaped as it approaches the head tube and bottom bracket junctures. As Ridley puts it, this system creates a clean transition from stiffness to comfort. Supporting this ideology, the rear triangle has been designed to intermix the two. The asymmetric, flat chainstays provide a stiff platform for power transfer to the rear wheel. Meanwhile, the ultra-thin seatstays create a vertically compliant ride quality without sacrificing rigidity.
And on the subject of rigidity, for all of the gram slashing going on, Ridley says that the SL is actually stiffer than the Helium. To be exact, Ridley's testing has concluded that the SL is 8% stiffer at the PF30 bottom bracket, 4% stiffer at the head tube, and the new fork design not only weighs 90 grams less, but it also has a 20% increased side stiffness. How does this translate to speed? In rudimentary terms, ride quality hinges on what's called a stiffness-to-weight ratio, or specific modulus. And while the mathematics behind the determination of specific modulus is too complicated to explain here, it's not a complicated notion to grasp that a frame with low weight and higher stiffness will efficiently transfer power.
For the build, Ridley spec'd the Helium SL with Shimano's revered Ultegra 6800 11-speed drivetrain. The crankset is the Rotor 3DF 52/36t, paired with an Ultegra 11-25t cassette out back. For the cockpit, the build features a 4ZA Cirrus handlebar and 4ZA Cirrus Barbore stem. Topping the 4ZA Cirrus Pro Carbon post is a Cirrus saddle, and in terms of wheels, the bike rolls on a pair of Fulcrum Racing 5s that've been cased in Continental GP tires.
The Ridley Helium SL/Shimano Ultegra Complete Road Bike - 2014 is available in five sizes, from X-Small to X-Large, and in the colors Grey and Matte Black.