CANNONDALE SUPERSIX EVO
How Cannondale redefined a modern classic
Cannondale’s SuperSix race bike is only a dozen years old, but it already brings with it a rich history, in both its design and pedigree. In 2011 came an update, the first of the EVO models, which was significantly lighter and a race bike that explored comfort as a performance benefit. Then, in 2015, came the secondgeneration EVO, which was lighter still and had a vastly improved ride quality. This second-generation SuperSix EVO was a true milestone bike, one that defined the era of lightweight carbon – it’s still a flyweight proposition today, five years later. It wasn’t just this that set the EVO apart, however, but a perfect balance of lightness and handling with a ride that wouldn’t beat you up. That it did this with a traditional frame shape and mostly round tubes gave it the air of a classic, and it’s most certainly set to become one. Today the EVO 2 (as it’ll now be known) is still a benchmark for how all race bikes should handle. Even in its final year of production it was helping teams to win massive races, such as Alberto Bettiol (EF Education First) at the 2019 Tour of Flanders.
Feel the love
The new 2020 bike, then, had a lot to live up to against a bike of such legendary status. David Devine, product director at Cannondale, candidly admitted to us: “We were probably a little behind in bringing out a new bike, such was the love and respect [at Cannondale] for the EVO. We absolutely knew that we needed to retain the sense of the EVO, its lightness, the handling and the ride.
The EVO is evolving its key values of light weight and – for the first time in terms of real aerodynamics – low drag, where less drag does deliver discernible benefits.”
The project took a full four years. Its head of aerodynamics, Dr Nathan Barry, has an engineering doctorate devoted to bicycle aerodynamics. He led Cannondale’s SystemSix aero bike project alongside the EVO’s development. “David’s brief for the project was: ‘save drag but don’t increase weight,’” Dr Barry tells us. “Aero efficiency has a huge effect on speed in cycling,” he continues, “so drag reduction was a priority, but the added complications were to retain its light weight and the responsive, composed handling that made the
previous bike so successful.” The 2020 Evo looks radically different from the old bike, particularly with its dropped seatstays, but not dissimilar to the new breed of race bikes, including the Focus Izalco Max, Specialized Tarmac and BMC Teammachine. Dr Barry explains that aerodynamic solutions are indeed similar across a range of bikes, just as they are similar in Formula 1 or other sports based around speed, but it’s the details in the EVO’s design that give it the edge.
Those details include a library of tube shapes that Dr Barry and his team developed around the EVO design. The SystemSix had deep aerofoil shapes in its build-up and many of them use kammtail principles to stay within rule constraints of the UCI, pro cycling’s governing body. A kammtail tube shape is a truncated airfoil. Think of the cross-section of an aircraft wing with the tail of the teardrop shape cut off. This shape ‘cheats’ the air into behaving as if the tail is still there so it acts in a controlled manner and doesn’t create a disruptive ‘wake’. This is known as separated (air) flow and creates relative drag in the opposite direction of the structure’s movement. With the EVO the tube shapes created are an evolution of the shapes of the SystemSix, more blunted in nature and much smaller in size to retain the low weight, which is at the heart of the EVO ethos.
“We developed a family of new low-aspect ratio tube shapes,” explains Dr Barry. “These are proven to reduce drag by over 30 per cent (at the wind tunnel test speed of 30mph) compared to the round tubes of the EVO 2, and if you take into account that at 15kph 50 per cent of your power is overcoming air resistance, the savings can make a big difference to every rider.”
Proof positive
Once the design was tested and proved from a structural perspective, Cannondale’s engineering team camped out at the low-speed San Diego wind tunnel to compare the new EVO against its main rivals. These were the Specialized S-Works Tarmac Disc, Cervélo R5 Disc, Trek Émonda SLR Disc and BMC Roadmachine SLR 01.
The test showed that the EVO had a significantly lower drag number than all of its rivals across a wide range of yaw angles.
This second graph shows these figures put into context using the yaw-weighted drag calculation developed by Dr Barry as part of his PhD in aerodynamics. His method combines drag across the range of possible yaw angles with the probability of riding at any given yaw angle, to give a single combined value (ie yaw-weighted drag). This value also takes into account wind speed, wind direction and rider speed, so it is a hugely complex calculation – it is an average of the drag on bike and rider for the whole of a ride (with up and downhills, corners, straights and a multitude of directions). From the graph you can see the EVO’s nearest rival (the S-Works Tarmac) carries the equivalent of nine watts more drag. (See table above left for detail.)
Gone with the wind
The EVO’s aero success is down to a combination of its tube shaping and the integration work that’s gone into the core of the bike. Up front, the top-end EVO models feature a new aerodynamic stem and bar system that was developed from the SystemSix’s unique KNOT design. This new KNOT bar and stem combo eschews a traditional clamp in favour of a cradle that the bar sits on (the bolts thread through the bar), and this cradle offers eight degrees of adjustment.
The bar, however, is much slimmer than the SystemSix’s aero design. It is still aero, but has been designed with light weight and comfort in mind. This KNOT bar/stem combo has a claimed 9.1 watt saving over a standard cockpit, and it’s an easy upgrade on any EVO model that doesn’t come equipped with it.
Towards the back of the EVO Cannondale has adopted a D-shaped seatpost, like nearly all of its rivals (as debuted by Giant on the TCX, and now found on bikes from Specialized, Cervélo, Chapter 2, BMC and many more). Cannondale’s is slightly different, however, as it is based on the dimensions of its slimline 25.4mm round tube standard. Cannondale claims this super-thin carbon seatpost is significantly more comfortable than the previous round post – and more aero, of course. The post sits into the frame using a new hidden seat binder (similar to that found on Cannondale’s Synapse but with
a simpler single-piece wedge). This binder weighs just 13g and, in combination with the new ultra-thin seatpost, saves 35g over the previous bike’s design.
The dropped seatstays run into Cannondale’s SAVE carbon chainstays – this is the biggest departure on the bike from the old model. We can see that this is where the new EVO will cop the most flak – with the dropped seatstays of race bikes from BMC, Focus, Specialized, Ribble and Canyon, to name a few, the old EVO had a point of difference in its classical design. But, as David Devine explained, the dropped stay design does have the proven benefits of improved comfort and better aerodynamics. If you’re looking to exploit every advantage available to you, then sentimental or stylistic designs are hard to justify.
When it comes to weight the new EVO hits the right notes, with quoted figures of 866g for a 56cm frame (fully painted with all fittings in place) combined with a 389g fork and the dedicated seatpost weighing 162.4g for the Hi-MOD frameset. The lower-spec BallisTec carbon model weighs in at 999g for the frame and 436g for the fork and uses the same 162.4g SAVE carbon seatpost. That makes the new frame Cannondale’s lightest disc frameset to date. For the BallisTec carbon rim brake model, weight is 976g and 368g for the frame and fork respectively, and it shares the same seatpost.
Keeping the wheels in place is a pair of Speed Release axles that we first saw on Cannondale’s SystemSix. They use a 12mm thu-axle that threads into the dropout just like a standard thu-axle, but the lever side features a slotted dropout. The double-lead thread on the axle means it will tighten and unscrew in five turns, rather than the usual 10. The axle then slides out partway, but it’s anchored via a slot in the hub (and a rubber ring on the axle) so it never needs to be fully removed, which makes refitting or switching a wheel both quick and clean because you don’t have to leave your greased-up thru-axle on the roadside while fixing a puncture.
Pole position
The EVO retains the same ‘performance’ ride position as the previous incarnation, sitting between the long and low position of the SystemSix and the shorter and taller geometry of the Synapse (and shared by the new
THEE VO’ SAERO SUCCESS IS DOWN TO A COMBINATION OF ITS TUBE SHAPING AND THE INTEGRATION WORK THAT’ S GONE INTO THE CORE OF THE BIKE
Topstone carbon gravel bike). It has, however, changed a little from the previous EVO, with my test bike having a 594mm stack compared to 584mm on the older bike, and a reach of 395mm compared to 399mm on the preceding model. The wheelbase has grown by 5mm up to 1005mm to make room for much more generous tyre clearances – up to 30c tyres with 6mm of clearance all round using wide carbon rims. The fork offset, trail and head angle are all basically the same, which instils the new EVO with the same handling character as the previous model. This is the key factor, over everything else, that gave the EVO the edge when it came to choosing our absolute favourite new bike for 2020, and crowning it Bike of the Year.
Hi achiever
The EVO isn’t all about the Hi-MOD pro level machine, though, in fact, most potential EVO owners will be looking to buy the more affordable BallisTec carbon version. We asked both Cannondale’s David Devine and Murray Washburn, director of marketing, about the differences between the models.
“I think more and more people are starting to look at the overall performance of the bike and what value it brings, rather than frameset to frameset weight comparisons,” says Devine. “In the case of a carbon frame vs a Hi-MOD frame in mid-price race bikes, the 150g added over Hi-MOD can mean that we can save hundreds of grams in the wheelset and add aerodynamics too. Ultimately, we test and develop to stiffness profiles that match on Hi-MOD and Carbon – so that 150g of weight becomes the main separator.”
“The goal is to make the two frames ride as similarly as possible,” explains Washburn. “They share moulds, engineers and much of the same material and layup. The difference is that, to achieve the desired stiffness and ride feel, we can either strategically place a few layers of high and ultra-high modulus fibres, which weigh less for a given amount of stiffness (and cost more), or we can use more layers of a less-stiff intermediate modulus carbon. Net stiffness is similar, just a few extra grams. Plus the high-modulus layup delivers a bit more fine feedback for at-the-limit cornering.”
David Devine gave us his final thoughts on the new EVO project. “To introduce new ideas, concepts or solutions that can improve a rider’s experience while also bringing them along as the platform evolves and changes – it’s the big challenge we face. We aren’t comfortable settling or standing still – we have a great pool of riders that associate with our race bikes. Truthfully, we know our purpose is to continue to learn and bring higher performance and faster products to those racers and riders. Even as the EVO changes, I think we have stayed true to this – so that provides some relief from the nerves!”
THE FORK OFFSET, TRAIL AND HEAD ANGLE ARE ALL BASICALLY THE SAME, WHICH INSTILS THE NEW EVO WITH THE SAME HANDLING CHARACTER AS THE PREVIOUS MODEL