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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. Its bouncing up and down so much you might think, Is that normal?. It is, perfectly normal. That is how an airfoil typically reacts to load. This was the example SCOTTs 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, not so good at creating stiffness. Of course, there are ways around this, creative lay-ups 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 UCIs 3:1 alter SCOTT engineers were liberated to experiment with tube shapes. The shapes they created dont 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). 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, SCOTTs tube shapes keep in mind it is a road bike. The wider shape gives them added stiffness and the subtly rounded rear of the tubes adds to this. Instead of an angular truncation the down tube and seat tube are gently curved which gives SCOTT engineers more flexibility with their carbon lay-up and allows for more complex layering in areas of increased stress.
If the Foils 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. Dont 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 4º 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 are the forks. Their lower bearing maxes out at one and a quarter inches, to keep frontal area down and trust an optimized lay-up 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. Its not until the wind angle becomes greater than 10º 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? Its because they have an ace up their sleeve. Those are numbers without a rider. So their bike wont 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 SCOTTs 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 25mph, but the fact that they can flop like this appears to validate SCOTTs engineering. To be fair there are some important bikes missing from the test, Specializeds Venge and the new Cervelo S5, reported to be the fastest aero road bike on the market.
Reinforcing SCOTTs 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 FOILs 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. Wed 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 56cm. 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 54cm, weighed 14.8 lbs. With a 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 and with the peloton tunnel still stuck in permitting, well 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 tempo, 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 404’s, 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 SCOTTs 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 doesnt feel quit 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.
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 down to the FOIL 40 with Shimano 105.
The Rider: Youve been on the fence asking your self, 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. Youre not looking for comfort, youre not even looking for some compliance. Youre wallet also has a 1:1 ratio.
SCOTT FOIL Premium
As Tested: 54cm Price: $11,999 Scott Foil HMX NET IMP Aero Carbon Frame, Shimano Di2, Ritchey WCS Carbon Cockpit, Zipp 404 Wheels, Fizik Arione CX
Fulcrum Speed 40T and Racing Zero offer the most modern... Read more →