The bike industry is accustomed to product evolution through small steps. When a new model of a bike comes out, it’s often pretty similar to the previous model, with a tweak to the geometry here, or a slight change to the lay-up there. It’s rare for a brand to unveil an update to a bike that represents a giant step in design and technology, which is what makes the new Specialized Venge ViAS so exciting.
Unleashed at this year’s Tour de France, the ViAS is Specialized’s first substantial revision of the Venge since its inception in 2011. It looks significantly different to previous Venges, and its creation required Specialized to bring together all its different divisions.
‘We applied all three arms of our research and development capability to design the entire bike system: computer simulation, lab and wind-tunnel testing, as well as on-road data acquisition testing,’ says Chris Yu, the man in charge of Specialized’s aero and racing R&D team. ‘We used computer simulation in both the aero optimisation of tube shapes as well as in the optimisation of the carbon fibre layup. We then tested numerous prototypes in our own wind-tunnel as well as in our structural lab. Finally, we collected actual ride data to assess both the aerodynamic and ride quality attributes of the system.’
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All aspects of the bike were designed in unison, and Yu claims the result is that the ViAS is two minutes faster over 40km than a ‘normal’ bike, and 60 seconds faster than the previous Venge. One of the most distinctive aspects of the design is the gull-wing bar shape, of which Yu says, ‘We found in our wind-tunnel testing that there was a significant aero benefit to a level stem. That meant we needed a way to get the handlebars back to where a rider would expect when using a traditional (eg -6°) stem. Rather than using spacers, which are relatively inefficient even when aero shaped, we found that getting the additional rise using the aero section in the handlebar resulted in minimal additional aero drag. As a result, the ViAS stem and bar combination achieves the same fit range as a traditional angled stem and flat bar but at a significant aero advantage.’
Braking new ground
Brake type and position are among the most controversial alterations to the Venge. The front brake is situated high, behind the fork crown to ensure it has a stable mounting base. ‘This balances aero performance, fork stiffness, as well as brake performance ,’ says Yu. ‘Many integrated V-brake designs compromise fork leg stiffness and as a result compromise the front end handling of the bike. An additional benefit of this orientation is that it allows a continuous surface from the back of the fork crown into the down tube, smoothing airflow.
The rear brake is situated part way up the seat tube, which Yu says is the lowest aero drag position when racing with bottles, while also being the location of minimal deflection between the rear wheel and the frame. ‘This results in reduced brake rub in sprint or high power climbing scenarios, to increase efficiency,’ says Yu.
the dropped seatstays not only improved aerodynamic performance, but also improved rear-end compliance
The ViAS is the first bike where Specialized has brought in-house the carbon composite techniques that its partners at McLaren use. To accommodate the novel internal cable routing system (no cables are on display) and dramatic aero tube shapes, new construction methods were used to package everything efficiently.
‘There are several features that address ride compliance, most notably the optimisation around wider [24mm front and 26mm rear] tyres. We designed a whole new wheel, the Roval CLX64, around wider tyres, which in turn served as the foundation to the ViAS design. By doing so, we were able to preserve aerodynamic performance while offering compliance and handling advantages that come with wider tyres,’ says Yu. ‘In addition, we found that the dropped seatstays not only improved aerodynamic performance, but also improved rear-end compliance.’
Having made so many changes, is Yu happy that the ViAS is a success? ‘We have tested the ViAS against almost every form of road platform available on the market. We’ve found that the ViAS represents a new class of aero road bike with performance on par with the majority of time-trial bikes today.’
A bold claim indeed, but we’ll reserve judgement until we do a full test in the future.
