October 25, 2005

Race Ready

Triathlete Magazine November, 2005

Scott USA breathes new life into triathlon with the Plasma By Jay Prasuhn It was late July in San Diego and former top pro mountain biker and triathlete Steve Larsen was driving the bike hard. Rivulets of sweat dripped from his brow as he pushed 282, 294, 302 watts. In the control room of the Allied Aerospace wind tunnel, the assembled onlookers sat slack-jawed.

No, Larsen’s presence was not part of a comeback from his recent retirement from the elite triathlon ranks, too much good opportunity as a real estate broker in his booming hometown of Bend, Ore. Rather, he was there at the behest of Scott USA Bicycles, and the looks of amazement were more for the bike underneath Larsen than for his display of raw power, impressive as it was. That bike was the Scott USA Plasma, a new ultralight, aerodynamic carbon triathlon bike that will make its debut in Kona under Kiwi Cameron Brown.

Larsen is Scott USA’s hired consultant in creating the Plasma. On this day, Larsen was testing the aerodynamics and positioning of this prototype of the Plasma, which was preceded by a real-world maiden voyage the day prior in Borrego Springs, east of San Diego.

Scott USA is a name synonymous with multisport (Former Scott employee, Boone Lennon, is credited with creating the first aerobars which graced early triathlon bikes, not to mention the time-trial bike that helped Greg LeMond win the 1989 Tour de France). The company left stateside sales for the European market but in 2003 re-entered the North American market, allowing us access to bikes previously only available in Europe, including the CR1 Limited road bike, an all-carbon creation that Chris Horner rode in the Tour de France this year.

In assessing this bike at first glance, one thing is clear: this is not a time-trial bike passed off as a triathlon bike as we’ve seen done before. All geometries and specifications on the flagship model, the Plasma LTD, are specific to triathlon: a 76-degree seat angle; Profile Design CBX Pro aerobars, a Fi:zi’k Arione Tri saddle, Zipp 404 tubulars.

FRAME JOB

Scott was certain they could build the lightest production carbon-fiber bike with their proprietary CR1 frame-building process. Traditionally, carbon-fiber frames are made one of two ways: pressed from a mold in the monocoque process or bonded together via lugs.

Now, there’s a third way: carbon welding. Think about how a titanium frame is tack-welded to hold a mitered tubeset in place, then finally welded tight. Now imagine that process with custom-cut, size-specific carbon tubes.

The laborious 26-hour process to produce one frame sees Scott’s Bio Cad design software create the lightest frames possible. With it, carbon tubesets that are cut to fit, mitered, held into position, and then essentially tack-welded together before the junction is wrapped with a sheet of carbon fiber and heated under pressure, a process that firmly joins the junction for a lightweight, strong frame.

Additionally, Scott’s process removes the constraints that typically force a carbon framebuilder to commit to a particular geometry for the lifespan of its mold. At any time, Scott can change frameset geometries.

GETTING AERO

The Plasma is the first tri bike with an integrated aero seat tube/seat post—just cut the carbon seat mast to fit your chosen seat height. The seat clamp allows for five centimeters of play up or down, so the seat height can be moved as you see fit (and also makes the bike saleable if you decide to sell it down the road). Weight-wise, it means no overlapping of seatpost material within the frames tubeset. All told, the frame is slated to weigh 800 grams, with the saddle clamp at 300 grams.

Scott will offer a bike case that will make travel with safe coverage of the mast tubing a viable option for frames that won’t fit in a traditional bike case.

Other elements to consider on the Plasma? It has a flat, ovalized top tube for lateral stiffness. As the tubeset extends back to meet the seatmast, it intersects it cleanly, making for a unique “bulls eye” cross-section when viewed from behind. The NACA teardrop downtube reaches down to that beefy bottom bracket, while the frame is completed with Scott’s own all-carbon aero fork and aero-sculpted vertical dropouts that tuck the wheel snugly into the seat-tube cowling.

While the top-end, race-ready Plasma LTD will retail at $6,500 with Shimano Dura-Ace 10-speed, Scott USA will offer two other models with the same frame geometries but a less-stringent variation of carbon fiber: the Plasma Pro, a Shimano Ultegra 10-equipped rig with Mavic Ksyrium Elite wheelset that will price at $3,500; and the $2,800 Plasma Team, outfitted with Shimano 105 group and Mavic Ksyrium Equipe wheels.

The bike made its race debut at Half Vineman, a successful one at that, when Larsen took it to an age-group win and earned a slot to race at the Hawaii Ironman, meaning there will be at least two Plasmas on the pier in Kona.