The U.S. bobsled team has a slippery new ride designed by BMW, and switching to the new machine has been something like going from a NASCAR racer to a Formula 1 car.

Engineers at BMW of North America spent more than a year developing a "truly improved and innovative" sled to replace the Bo-Dyn bobsleds designed in part by NASCAR veterans at Bodine racing. The new carbon-fiber bobsleds, which draw heavily on the automaker's experiences with advanced materials and aerodynamics, could give the U.S. squad its first two-man Olympic gold medal since 1936.

"The design is similar as to how we would approach a car, how aerodynamics and structures work together," says Michael Scully, creative director of BMW's Designworks USA. "It's all very familiar from a design standpoint, but unfamiliar from a bobsledding point of view."

BMW knew very little about bobsled design, of course, but it knew it could do more than provide a lot of cash when it signed on to sponsor the U.S. Olympic effort through 2016. The U.S. Bobsled and Skeleton Foundation sought the automaker's help bridging a "technology gap" with stronger teams, primarily those in Europe.

The two-man bobsled made its competition debut Jan. 19 in Austria, placing 14th out of 30 entries. Not bad, considering the team had minimal experience with the sled. Things were looking up during the Feb. 3 weekend in Switzerland, where the Americans topped the time sheets in a practice session and finished fourth in the race with their new BMW. Of more interest to the team and designers who continue refining the bobsled, the BMW bobsled claimed the highest top speed during practice at just over 90 miles per hour on the St. Moritz track, typically the fastest track on the competition calendar.

"That was really gratifying and reassuring that we are heading in the right direction," says Scully. "You can't simulate the track in every single nuance, there's so much roughness and sliding. Wind-tunnel testing and modeling doesn't cut it."

All the variables a team encounters on the track prompted BMW to follow a slightly different path designing the new bobsled. Rather than copy a design that has been largely unchanged since the U.S. team started using it 20 years ago, Scully drew on decades of motor-racing experience, including his work on the Formula BMW open-wheel race car that is a stepping stone for up-and-coming racers worldwide.

The auto designer says his team came to the job with open eyes and a measure of humility, realizing that they knew next to nothing about sliding down an icy track. Automobiles typically follow a straight path, and there usually is not much sliding or going sideways. That stands in contrast with bobsleds which, despite following a relatively narrow track, rarely go in a straight line as they approach 100 mph and the athletes experience up to 4Gs through 90-degree banked sections of the course.

"The sled is going through so many different positions, and it pitches and yaws," Scully says. "It's very rare that the thing is heading straight. You can apply traditional aerodynamic approaches, but we realized that the positions are so varied that minimizing to the bare minimum requirements is better than a classic airfoil shape."

Aerodynamics have evolved somewhat slowly in bobsledding. The sleds that appeared in the first Olympics were rather simple affairs, not much different than what you might see kids playing with on a winter day. There were no aerodynamics to speak of, just bulky sweaters protecting racers from the wind. Small fairings appeared at the front and back of bobsleds in the 1950s, and the aerodynamic skin covered ever-more of the sled until it completely enveloped the sled in the design we're familiar with today.

In recent decades designers tried to optimize the aerodynamic design by wrapping the bobsled in a classic teardrop, airfoil shape. But Scully says the highly dynamic path a bobsled follows down the track means optimizing aerodynamics as you would on an airplane isn't necessarily the best idea. Instead the team looked at the tightly regulated dimensions dictating the dimensions of just about every component on the bobsled, as well as the bobsled itself, and basically shrink wrapped it in a carbon fiber cover.

Scully and the team are keeping quiet on the sled's exact dimensions, but it's worth noting the official rules stipulate that a two-man bobsled be no smaller than 2.7 meters (8 feet, 10 inches) long weigh at least 170 kilograms (374.8 pounds). Scully also would not elaborate much on the design of the bobsled, but said they tried to drape the sled in a minimalist aerodynamic cover instead of designing the optimal aerodynamic bodywork for straight-line speed. It's akin to ditching NASCAR bodywork for the sleek, form-fitting shape of an F1 car.

There's still a ways to go to find all of the pieces that will come together in a win for the team. But U.S. team hopes to continue refining the design and gaining familiarity with the new machine as it continues shaving thousandths of a seconds off its time.