12 of the fastest aero road bikes
Aero road bikes are hot stuff right now. We take a look at 12 leading contenders from BMC, Cervelo, Canyon, Giant, Scott, Trek, Specialized, Felt, NeilPryde, Avanti, Ridley and Boardman
The future is aero. Look at many of the bikes and products released in the last couple of years and it's easy to see the industry is focusing on aerodynamics. More and more manufacturers now stepping up to offer aero road bikes, arguably the biggest trend in road cycling right now, so we've rounded up 12 of the fastest for you.
Aero road bikes essentially draw the aerodynamic features from time trial bikes into a road frame, and balance the demands of weight and stiffness into a package that, on paper, looks to be the ideal all-round choice. There's a lot to be said for aerodynamics when cycling. Slice through the air cleanly and with less drag and you’ll go faster, or ride at any given speed with a lower power output. Who doesn't like the sound of that?
While the body makes up the chunk of that wind resistance - it’s about 80% - the bicycle is still a significant factor. It's enough for engineers and designers to focus on making road frames and products more slippery in the air. In the pro peloton aero road bikes have been quickly adopted, where the margins of victory are very slim and there has been a focus on gaining ever smaller performance gains over the years.
Weight, and the lack thereof, used to be the main driving force of frame development. Along with stiffness, these were the two cornerstones of bike design. These days most bikes are light, many well below the UCI’s 6.8kg weight limit (which doesn’t affect us non-racers anyway), and come with more stiffness than is sometimes comfortable.
So aerodynamics is becoming more important for manufacturers. We’ve recently heard the news that Specialized have built their own wind tunnel and the Belgian cycling industry is going to invest in its own tunnel too. Despite most manufacturers testing in wind tunnels, aero road bikes don’t look identical. There’s a lot to be said for interpretation of data. There are shared design trends though: skinny, aero-shaped tubes, integrated brakes, and internal cable routing.
With all that in mind, we decided to take a look at the current offerings, and we’ve rounded up 12 aero road bikes below. These aren’t bike reviews, but where we have reviewed the bike previously we’ve linked through to the relevant article.
The whole point of the S5 is that it’s an aero road bike, nicking ideas and features from Cervélo’s all-conquering time trial range. So, you get ultra skinny tubes and a tiny frontal area. Walk directly away from it 10 yards and you might never find it again. Okay, that’s not true, but you get the idea – it’s thin.
The cutaway seat tube smooths the airflow from the frame to the rear wheel while the dropped down tube does a similar job further forward, smoothing the airflow from the fork to the frame and minimizing the turbulence behind the fork crown. The head tube is an hourglass affair with a cinched in waist, the seatstays are crazy-thin and they manage the airflow over the rear brake caliper. Want a few more aero features? The seatpost is like a knife-edge, the cables run internally… Aerodynamically speaking, there’s a lot going on here.
The Cervelo S5 range includes two models, the S5 Team and S5 VWD, with frameset prices starting from £2,999.99.
BMC TimeMachine TMR01
The development of the TimeMachine happened at about the same time as that of the TM01 time trial bike, introduced a year ago. The design process for that bike shaped their understanding of aerodynamics and how to overcome the challenge of managing airflow within the UCI's strict regulations. With such a depth of understanding it was clear there was an opportunity to apply the same logic to a road-going machine.
There are several principles key to the TMR01. First is the use of the truncated wing profile (not unlike a Kamm tail) for the main sections of the frame. To reduce the degree of turbulent air BMC use Tripwire, their name for a smooth groove at the leading edge of forward facing sections. This delays flow seperation and keeps the air attached for as long as possible, minimising drag - in essence it's doing the same job as the dimples on a golf ball.
Another key design consideration is summed up with their Sub A concept, which aims to minimise the frontal area of the frame. Visually the front end of the frame is as narrow as it's possible to conceive, but the most dramatic design solution here is the integration of the front brake into the fork and the addition of the carbon 'shroud', a non-structural element attached to the fork crown, sitting just ahead of the head tube and clamping to the steerer tube beneath the stem. It acts as a cable guide too.
The TMR01 is available with three builds starting with Ultegra costing £4,100.
Giant Propel Advanced SL 3
The Propel marks the first time Giant have offered an aerodynamic road bike. It’s been some years in development, with Mark Renshaw and Theo Bos involved in the project. Giant say the bike has been designed to be as light and stiff as their current flagship road bike, the TCR Advanced SL, but offering the aero advantage that many professional racers demand these days.
Key to the frame is the AeroSystem Shaping technology that is the result of Computational Fluid Dynamics (CFD) research and wind-tunnel tests. Every tube has been carefully shaped, with a teardrop shape in evidence wherever you look. Interestingly, the down tube has been shaped with a water bottle in mind. It’s flattened where the water bottle normally protrudes from the sides of a conventional down tube.
Giant are intially just offering the Propel Advanced SL 3 costing £4,499.
Scott first launched their Foil aero road bike back in 2011, one of the first manufacturers to devote time to designing a road bike that reduces drag with technology borrowed from their Plasma 3 time trial bike. Such was their confidence in the Foil that they dropped the Addict and expanded the Foil to cover a wide range of price points. That's faith in aero.
It's a striking looking bike. The tube shapes have a partial airfoil shape with the trailing edge chopped off, which tricks the air into acting as if there was a trailing edge. It’s similar but not the same as the truncated Kamm tail used by Trek on their Madone. Scott say that it gives the same aero performance as a 3:1 profile tube but without the extra weight. Unlike some bikes, Scott have stuck with regular caliper brakes rather than integrating them into the frame.
The Foil extends to eight models starting from £2,199 for the Foil 40. While the frames all share the same aero technology, the main distinguishing feature is the different grade of carbon fibre used.
In contrast to some other models out there, the Alize's tube shapes are surprisingly chunky with nary a teardrop profile in sight. Whereas traditional aero bikes feature aerofoil shaped seat and down tubes that are prone to flex and can perform poorly in cross winds, the tubes on the Alize have been designed to act as a complete package enabling wider, stiffer and lighter tubes to be used.
Of particular interest is the lower third of the down tube which features what Neilpryde call an 'Extended Kammtail'. The kamm tail is the latest buzzword in the cycling world. In effect it's an aerofoil with the tail sawn-off, and has been used on cars since the 50s. What Neilpryde have done, however, is extend this concept so that both the down tube and seat tube act as a single kammtail aerofoil enabling them to increase the size of the down tube without damaging aerodynamic performance.
The Alize can be had in four models beginning with a Shimano 105 bikes costing £2,199.
Specialized S-Works Venge
The choice of Mark Cavendish, Specialized’s first foray into aero road bikes has been a successful one. The Venge was the result of a collaboration with F1 team and car manufacturer McLaren, who helped develop the aero frame before its launch in 2011.
The frame draws on the F1 team's aerodynamic expertise with a a 3:1 airfoil fork with a narrow leading edge, along with a narrow (1 1/8in at the top to 1 3/8in at the crown) tapered head tube to minimise the frontal area leading to a reduction in drag. The shaped seat tube curves around the rear wheel and the seat stays have an airfoil shape with a flat outer surface and rounded inner surface to improve the performance in crosswinds. Naturally, cables are routed internally. Specialized claim it saves 23W at 45kph compared to their SL3 road frame.
The Venge is sold in four models starting with thje Venge Comp costing £2,500 with Shimano 105.
Ridley Noah Fast
The Noah Fast frame has four key themes; aero shaped tubes, integrated brakes, slotted forks and stays, and F-Surface. We’ll start with F-Surface because we can’t think of any other road frame that has this - Ridley have been using it on their Dean time trial bike for a couple of years now. Applied to the leading edges of the head tube, seat tube and seat mast, is a 5mm-wide raised strip that is designed to delay flow separation and keep the air attached for as long as possible.
In aerodynamic fields it’s called a turbulator. When air passes over the frame, the layer of air closest to the surface is the boundary layer. Near the leading edge of the tube this boundary layer will be laminar, but in its journey across the tube the air becomes turbulent and will eventually separate from the surface. This separation point causes drag, because of the lower pressure behind this point. These strips move the separation point further along the tube profile closer to the trailing edge, by forcing the boundary layer to be turbulent (rather than smooth laminar) which has the effect of delaying the point of separation
Ridley have actually designed the mini V-brakes as part of the carbon structure of the forks and seat stays. The other key aerodynamic feature is what they’ve dubbed F-Splitfork technology, and which amounts to slots in the fork and seat stays. This is a technology component manufacturer Oval Concepts developed a few years ago in their Jetstream fork, and which they licensed to Ridley for use in their Noah.
The Noah Fast starts from £4,940.
Canyon Aeroad CF
German manufacturer Canyon brought out their Aeroad, their first ever aero road bike, in 2011 and it has been pressed into service this season under the Katusha team, a common sight in breakaways. Joaquim Purito Rodriguez rode an Aeroad CF for his Giro d’Italia and Vuelta a España stage wins last year.
The frame has been designed to reduce the frontal area, so there’s less bike to push through the air. To that end the head tube is narrower than that of their regular road frames. The down tube is deeply ovalised, there’s a skinny seat tube and the cables are all routed internally.
There's eight models to choose from starting with the Aeroad CF 7.0 at £2,249.
Felt were one of the earlier adopters of aerodynamics in a regular road bike, bringing out the AR way back in 2008. The airfoil-profiled down tube is deep – it varies but it’s never less than 65mm – and shadows the line of the front wheel, while the seat tube moulds around the leading edge of the rear wheel to smooth the airflow there. It's one of the bikes here that looks more like a time trial frame with drop handlebars.
The top tube has a shield-shaped profile – it’s flat-topped with curved sides and tapers considerably as it slopes gently down to the seat tube junction – and the seat stays are slim, not to say skinny, in contrast to the meaty chainstays.
There's five bikes in the AR range, starting with the Shimano 105 built AR5 costing £2,000.
Trek Madone 5, 6 and 7 Series
The most important aero feature of the Madone is the KVF aero tubing. KVF? It stands for Kammtail Virtual Foil and it was first introduced on Trek's Speed Concept time trial bike. The KVF tube profile is an airfoil shape with the tail chopped off square. Trek reckon that the design makes the air behave as if the tail was actually there in order to reduce drag. The advantages of cutting the tail off are that it uses less material and so reduces weight; it works well in crosswinds; and it allows Trek to stay within the UCI's equipment rules.
You can see the KVF shape most clearly on the down tube – the sides curve around and then the rear edge is cut off flat. Trek use the same shaping on the head tube, seat tube, the seat stays and the upper portion of the fork blades. Integration has become ever more important in bike design recently with manufacturers seeking to reduce drag by making everything blend together for more aerodynamic efficiency.
Trek have been busy creating their own new front brake that fits neatly to the fork - it's badged up as belonging to their in-house Bontrager brand. One arm of the Bontrager Speed Limit brake is attached via a central bolt, the other fixes direct to the fork leg. This saves a little weight and allows the two arms to sit flush against the fork crown. Trek reckon that the combined effect of the KVF fork shaping and the integrated front brake reduces drag by another 76g.
Trek share the aero features across three platforms, the 5, 6 and 7 series Madone. While they share the same tube shaping and rear brake placement, they differ in the carbon fibre manufacturing, the 6 and 7 series are built in the US while the 5 is made in the Far East. They also use different grades of carbon fibre. The Madone 5.2 costs £3.000, that's your entry into Trek's aero Madone range. The price rises to £4,900 for the Madone 6.5 and £9.119 for the Madone 7.
Avanti Corsa DR
Integration has been key to this bike, and there are no frivolous styling details: function leads form here. The aerodynamic and engineering requirements have led to the shape of the bike. In a first that we know of, the quick release skewers are integrated. By this we mean they are designed to sit flush with cutaway sections in the fork and seat stays. The top headset spacer is even aero shape, and the minimal seatpost clamp is seamlessly integrated into the frame.
You can choose from five Corsa DR builds, starting with the Corsa DR 1.0 at £2,200.
Chris Boardman knows a thing or two about aerodynamics, winning the individual pursuit gold medal at the 1992 Barcelona Olympics on his Lotus 108 superbike and breaking the hour record on three occasions. He’s known as the Professor, on account of his attention to detail, and has been significant in his involvement with Team GB in developing their aero track frames.
The AiR in his signature range of road bikes borrows heavily from the stunning AiR TT bike. The frame has a deep section down tube, internal cable routing and a fair amount of melding together at the point where the top, down and head tubes meet. There are flat surfaces on the inner faces of both the fork and rear stays, designed to work with deep section wheels and ensure that airflow smoothed by the wheel isn't disturbed by a more traditional section fork blade.
Six models in the AiR range span price points from the £1,999 AiR 9.0 up to the £5,499 AiR 9.8.
Will you be eyeing up one of these for your next road bike purchase?