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By Lennard Zinn
On Friday, as the Tour de France headed to Karlsruhe, Germany, Gerolsteiner’s Fabian Wegmann rode solo for hours on his carbon Specialized S-Works Tarmac. However, once the race hits the mountains, two of his teammates, namely Levi Leipheimer and Georg Totschnig will be riding the even lighter, next-generation S-Works Tarmac SL frame and all-carbon S-Works fork.
The SL shares the Tarmac’s geometry. Yet, because Specialized tweaked both tube shapes and dimensions while custom tuning the orientation and number of layers of carbon, the SL has been designed for maximum shock absorption, road grip and vertical compliance. At a claimed weight of 895 grams for the Tarmac SL frame and 300 grams for the fork, this is one lightweight unit, although I don’t know if that is for Leipheimer’s 52-centimeter size or a larger one. Specialized says to expect the Tarmac SL frame and fork to cost about 40 percent more than the current S-Works Tarmac chassis.
Specialized calls its manufacturing method for the SL “FACT Az1” and claims that it yields a frame with the highest stiffness-to-weight ratio available. Specialized customized the amount and placement of FACT carbon for all six frame sizes to make the SL even lighter, more comfortable and better handling.
As the final step in putting the SL way below the 1-kilo mark, Specialized employed carbon dropouts and did away with the primarily cosmetic woven outer layer of carbon. Starting with such a light frame, the Union Cycliste International’s minimum weight of 6.8 kilograms (just under 15 pounds) is easily accessible with standard components.
“We designed the SL to be more efficient, more compliant and better accelerating than any bike on the market,” said Specialized’s director of engineering, Mark Schroeder. “The fact that it’s also the lightest chassis out there was simply a bonus.”
Gerolsteiner uses a full Dura-Ace group and Ritchey stem and bar, but the frame will sell with a carbon S-Works FACT crank, tipping the scales a full 165 grams lighter than a Dura-Ace crank and bottom bracket, and said to be stiffer. The bottom bracket shell is oversized, and the oversized aluminum spindle is integrated with both arms and attaches in the middle, as Sweet Wings pioneered a decade or so ago.
The SL will also come with Specialized’s Barmac FACT carbon bar/stem, which weighs 349 grams and has optimized, multi-position ergonomics. The carbon bar is molded together with a custom stem, but since Kestrel has patented one-piece molded carbon bars, this bar is three pieces. However, this is an advantage for Tour riders, since most teams insist on a deeper, more rounded curve to the drops. With the three-piece bar mold, Specialized can just switch the molds for the lower part when molding the bar to get that curve without having make an entire mold to supply just a few pieces for the team.
Specialized also bought the rights to the Roval name from its founder, French engineer Claude Lehanneur, and the upshot is the Roval Rapide Carbon wheels, which have a mid-section carbon rim weighing just over 400 grams. Add an alloy freehub and DT Revolution spokes, and the Rapide’s mass comes to just 1550 grams per pair.
Specialized Optics created the 16-gram Arc sunglasses that Leipheimer uses, with curved, non-folding titanium temples. A recently declassified military lens material, NXT, used for helicopter windshields, makes for tough, shatter-proof use. The color-changing Adaptalite photochromic die in the lenses really works, allowing them to automatically adapt to a wide range of light conditions. Specialized engineers tuned the pantoscopic angle (the vertical orientation of the lens relative to the eye) of their optics for distortion-free vision in a range of common cycling positions.
Followup: I received a number of questions about the Gerolsteiner time trial bikes and who makes them. They are made by Walser in Switzerland. All of them except Leipheimer’s feature a super-narrow bottom bracket shell (and Specialized made custom spindles 15mm shorter on Dura-Ace cranks for the team for them) and 110mm rear hub spacing. Leipheimer’s uses a standard-width BB shell with a standard Dura-Ace crank and a standard 130mm rear hub spacing.