While the Bianchi Oltre XR2 marked a significant turning point in the company’s commitment to their aero race bikes, the Oltre XR4 – whilst displaying obvious changes in its form – is more an evolution of the XR2 both visually and at it’s core.
Though touted by Bianchi as an all-rounder, the Bianchi Oltre XR4 is unquestionably and Aero Race machine and the bike of choice for the LottoNL-Jumbo Team. Taking design elements from their Aquila CV Time Trial bike such as the tapered aero, 1.1/8” to 1.1/4” head tube and bladed fork design, and extending the aero elements of the down tube, seat tube and seat stays, the XR4 is visually more aggressive than the XR2 and the addition of a Vision Metron 5D integrated handlebar and aero wedge seatpost enhance this aesthetic on the complete bikes. Pleasing as this may be to the eye, the obvious benefit to the rider comes from the frame’s reduced drag. Bianchi, while not releasing test results, claim that the frame offers a 20 watt improvement over the XR2 – largely a result of the aerodynamic improvements. This is no small gain and will be welcome news for those racing the XR4.
Deeper aero tube profiles come with secondary side effects, namely increased stiffness, which brings its own benefits, and historically, less comfort.
Taking the enhanced stiffness as a stand-alone aspect, the Oltre XR4 retains the BB86 bottom bracket of the XR2 and the BB area is noticeably over-engineered for power transfer. In addition the new, wider, straight seat stays are bigger partly for stiffness but also to allow for dedicated internal routing for mechanical and electronic groupsets, which also serves to reduce the frame’s drag. Thanks to these refinements and the elemnets already discussed, the XR4 demonstrates improved handling over its forbear offering lightning fast reactivity and pin-point handling characteristics. These aspects are perfect for responding to moves in the bunch, be that on the climbs or in a sprint, and having the bike instantly respond to your input and directional changes makes for a confidence inspiring ride. There is no doubt that the XR4 is a nimble and fast machine – not only is it quick to gain speed, but thanks to the improved aero profile it is adept at holding that speed, taking the effort level down noticeably.
As previously mentioned, early aero road bikes were something of a double-edged sword, obviously more aerodynamic but also heavier and quite uncomfortable for many to tolerate over long rides – let alone 3 week Grand Tours. Over the last decade there have been dramatic improvements in carbon technology that have helped reduce the weight on aero frames to levels comparable with standard tube bikes and despite a 40g weight gain over the XR2, the XR4 is only 980g (55cm frame) which is low considering the aero profile. The noticeable ‘hard’ ride feel of aero bikes has been tamed - for the likes of Giant and Felt who have excellent aero race bikes - with improved materials and clever carbon lay-up while the shaping of stays is often used to temper the harsher ride feel.
In most bikes of the calibre of the XR4 there would be a heavier compromise between stiffness and road-taming vertical compliance at the back end, in order to keep the bike from bucking around beneath the rider and destroying the control of the ride whilst simultaneously improving the comfort of the bike so as to punish the rider less. Like the Specialissima, the XR4 reconciles these opposing qualities by employing CounterVail.
Bianchi have exclusive rights to Material Sciences Corporation’s CounterVail material. It is the material that has helped create the success of Bianchi’s Infinito endurance bike, the Aquila TT bike and the Specialissima climbing machine.
Originally developed for use by the US Military as a stealth technology and widely used in Helicopter and Aircraft cockpits, Countervail is a fibre reinforced visco-elastic material that substantially reduces vibrations
The video below is a simple visualisation of the vibration cancelling properties of Countervail and goes a long way in demonstrating how valuable the material is when applied to stiff, aerodynamic road bikes. It is the reason that Bianchi can maintain the deeper aerodynamic tube profiles without punishing the rider in terms of comfort or handling.
The evident damping qualities of CV have been used to great effect in Bianchi’s endurance Infinito range and in the Specialissima, both of which have improved traction (vibrations can lead to the rear wheel bouncing beneath the rider) and inherent comfort, both qualities in turn lead to a more stable ride and a fresher rider.
Aside from the reduction of fatigue and the improvements to control, Bianchi also say that as a result of a ride that is less punishing, it is easier for a rider to maintain an aerodynamic position for longer periods of time. Consequently, as a rider is around 80% of the aerodynamic drag, there are significant gains to be had over the course of a race or long ride.
The Oltre XR4 is an entirely internal, dual routed frameset meaning that whether you opt for mechanical or electronic shifting, the frame is exactly the same. Ultimately these little details mean that you are future-proof when it comes to groupsets and as the frame is the most important part of the bike, those who may be at the limit of their budgets can at least access the XR4's stunning quality, safe in the knowledge that their are multiple upgrade paths.
Unquestionably a race bike, the XR4 becomes even more enticing thanks to its improved aerodynamics, stability and comfort. Designed to optimise your power transfer to the road, to be efficient and to respond immediately to the changes in pace experienced in races: it delivers on all counts while lending an aero helping-hand. Indeed, it is one of the most responsive race bikes we have ridden and this is most noticeable when you hop out of the saddle and stand on the pedals to climb, for a sprint or to chase a man down.