The Merida Reacto has always been a class leading aero bike, combining state of the art aerodynamics with rider comfort. The 4th generation model is more slippery and beautiful than ever, incorporating wider tyres, much neater cockpit cable integration and a series of incremental improvements to boost performance. In the world of Pro-Tour racing no area can be ignored. Computational Fluid Dynamics (CFD) calculations were used to model performance in a virtual wind tunnel, guiding the changes which offered the most aerodynamic benefit: Prototypes were wind tunnel tested following the German TOUR magazine standard, including themoving leg dummytest. The Reacto CF5 needs just 209 watts effort for 45 km/h speed, 1 watt faster than its predecessor so it's in the leading group of aero road bikes ever tested by TOUR magazine.Small details such as integrating the front disc cooler behind the fork and the rear disc caliper in the rear triangle and creating new bolt through axles with the