Tech-Redux: SCOTT Foil Premium From issue 9 (Feb-Mar 2012)

Next time you are on a flight, grab a window seat. As you taxi down the runway look at the wing tip. Is it bouncing up and down? Of course it is. It’s bouncing up and down so much you might wonder if it’s normal. It is, perfectly normal. That is how an airfoil typically reacts to load. This was the example SCOTT’s Lars-Erik Johnson gave me when we began discussing their new Foil, an aero bike with a decidedly different approach to aero. Airfoils are great at sculpting wind, but not so good at creating stiffness. Of course, there are ways around this, creative layups and high mod materials, but SCOTT threw all that thinking out.

They took a look at their Addict, a bike that won repeatedly on every kind of terrain imaginable, from sprints to Alps, during its tenure with HTC. Why did they want to start over, thinking airfoils first? They decided to take the characteristics of the Addict—the stiffness, the low weight, the race ready geometry—and add to all of that aero performance. Simple right?

By not falling to their knees at the UCI’s 3:1 alter SCOTT engineers were liberated to experiment with tube shapes. The shapes they created don’t look like the aero bikes we have come to expect. Perhaps this is because, unlike airplanes and F1 cars, cyclists are the snails of aerodynamics. While each and every tube shape has been optimized for the specific airflow it will see, the down tube and seat tube, the typical signifiers of aero, are wide, short tubes. They use an airfoil front section, but it is then truncated and rounded off at closer to 1:1 (length-width ratio). This is called “forced flow separation” and causes the airflow to act as if the airfoil has not been truncated. While Trek, and the Kammtail design of their Speed Concept use similar thinking, SCOTT’s tube shapes keep in mind it is a road bike. The wider shape gives them added stiffness and the subtly rounded rear section of the tubes adds to this. Instead a of an angular truncation the down tube and seat tube are gently curved, which gives SCOTT engineers more flexibility with their carbon layup and allows for more complex layering in areas of increased stress.

If the Foil’s down tube lines were carried beyond the truncation, they would in fact dovetail nicely into the seat tube itself giving them an almost 9:1 ratio as far as airflow is concerned. SCOTT calls this interaction between down tube airflow and seat tube airflow “fuselage interaction” and it is one of the defining principals of the bike. Don’t just make each tube aero, make them work together as a unified force. By utilizing a wide down tube the water bottle is hidden from airflow and the seat tube has to split less air. The rear seat stays are canted 4 degrees to better handle the angle of airflow coming off of the seat tube. The top of those seat stays are sculpted to create a shadow in which the rear brake can hide. Even the chain stays, as they trend out to accept the wheel, are optimized for clean airflow. The only 3:1 shape on the entire bike is the fork. Its lower bearing maxes out at one and a quarter inches, to keep frontal area down and trust an optimized layup to produce the required stiffness.

SCOTT used the Mercedes-Petronas Grand Prix tunnel to test their findings and are upfront about one fact: while significantly more aero than a standard road frame, the bike creates more drag than a Cervelo S3 or Felt AR1 in shallow wind angles. It’s not until the wind angle becomes greater than 10 degrees that the wider tubes come into their own. So their new aero road bike is slower than other aero bikes already on the market? Why would they publish those numbers? It’s because they have an ace up their sleeve. Those are numbers without a rider. So their bike won’t be the fastest on the roof of your car. Just like the way each tube is designed to create an aerodynamic package, SCOTT created the bike to be aero with a rider disturbing the airflow. According to SCOTT’s numbers the bike is more aero than the S3 or the Felt AR1 once that rider is placed on it. The numbers are close, not separated by more than a few watts at 25 mph, but the fact that they can flop like this appears to validate SCOTT’s engineering. To be fair there are some important bikes missing from the test, Specialized’s Venge and the new Cervelo S5, reported to be the fastest aero road bike on the market.

Reinforcing SCOTT’s claims that the bike is truly about well-rounded performance are numerous features unrelated to aerodynamics, features designed to create a stiff and nimble race bike. The down tube flares to meet the bottom bracket to create a stiffer platform than the Addict, but using thinner walls and less material to keep weight and stress down. The carbon used is, of course, very high modulus, called HMX, an exclusive creation for SCOTT. Other nice touches on the bike abound. The seat binder is integrated in the top tube and is the cleanest on the market. All the cables are internally routed, mechanical and electronic, and while the post is a Ritchey custom using their FOIL tube shape, it offers traditional seat post adjustability.

Our test bike, the FOIL Premium Di2 with Zipp 404s, is an example of the “murdered-out” look that is invading the cycling industry. This is the black-on-black styling that has found its way from East LA low-rider culture all the way to West LA Range-Rovers. The FOIL’s matte black paint, gray highlights and logo treatment are subtle, but detailed, although the word “Premium” does seem unnecessary. The Di2, 404s and Ritchey WCS cockpit speak for themselves. An important caveat to the good looks: matte paint is essentially impossible to keep clean. Our one request: put the Di2 battery under the down tube or on the non-drive side chain stay. Our test bike also shipped with the integrated Flight Deck computer. While this does away with the junction box, its look and functionality feels like 8-Track technology. We’d rather run the junction box and choose our own computer.

With frame weight being part of the design brief SCOTT was able to get the FOIL under 900 grams for a 56 cm. While not the lightest frame around by some stretch it is lighter than a Tarmac SL4 and way lighter than most aero frames. Our bike, a 54 cm, weighed 14.8 lbs. With a SRAM Red build and some shallow aluminum clinchers the bike would be scary light out of the box.

Trying to verify if a bike produces X grams of drag fewer than another bike at X mph is best left to the wind tunnel, so we’ll focus on the other qualities, the stiffness, the ride feel, the overall abilities of the FOIL. One sensation was prevalent with the FOIL: efficiency. In every situation, sprinting, climbing, rolling at temp, the bike feels incredibly efficient. It feels pounds slighter than bikes only a pound outside its weight class. As you ramp up the speed the bike feels as if it disappears beneath you. Where you interact with some other bikes, under power the FOIL becomes an extension of you. The weight, or absence thereof, the air-splicing 404s, and the feather touch electronic shifting removed all the distraction of the bike’s mechanisms and left only the sensation of the effort itself. This is “sum-of-the-parts” performance and a vindication of SCOTT’s approach to the FOIL. It is an all around race bike that is aero, not an aero race bike.

Despite sharp angles and a fairly tight wheelbase, the bike doesn’t feel quite as tight and sharp as some others during full-tilt descending. It asks to be pointed and some commitment is required to really lay it over, but once pointed will go from point A to point B in the most direct route possible. The stout rear end, a source of so much power transfer, is also a source of confidence at speed.

After an hour or two, another sensation is added to this feeling of efficiency: stiffness, and not the bottom bracket kind. The FOIL is uncompromisingly stiff. On most roads it adds up to important feedback, but once the road breaks up, it amplifies every bump. The bike will never be called comfortable, a trait incidentally it also shares with the Addict. We have heard rumblings of a new seat post designed to provide some comfort. If it exists we’ll probably see it on the GreenEDGE FOILs at Roubaix this spring. Stay tuned.

Of course, there is comfort in knowing every amount of energy expended is applied to forward movement, in knowing the exact same effort applied elsewhere isn’t going to go as far or as fast. The Scott FOIL brings pure originality to its design and returns one to the belief that a jack-of-all-trades solution can be watt for watt as efficient as an aero-specific road bike, and gram for gram as light as climbing-specific one, too.

Builds
In addition to the FOIL Premium, SCOTT offers six other builds to take advantage of their new frame, from the FOIL Team issue with SRAM Red to the FOIL 40 with Shimano 105.

The Rider
You’ve been on the fence asking yourself, “Do I get an aero bike or a climbing bike?” You need the utmost efficiency in every situation your club ride can throw at you. You’re not looking for comfort, you’re not even looking for some compliance. You’re wallet also has a 1:1 ratio.

The Bottom Line
Price: $12,000
Size tested: 54 cm
Group: Shimano Dura-Ace Di2
Wheelset: Zipp 404
Details: SCOTT FOIL HMX NET IMP Aero Carbon frame, Ritchey WCS Carbon bar and stem, fi’zi:k Arione CX