At the TDU this week I noticed a lot of the new road bikes that the pros are using all seem to look very similar. It seems like a lot of brands have moved away from the full aero designs that we've seen in the past, and are now opting for a more traditional look.
Many of the new road bikes on the market seem to resemble the Specialized S-Works Tarmac or the Colnago V4RS. These bikes have a more classic look and feel to them, with clean lines and minimal aerodynamic features.
I'm curious to know what everyone else thinks about this trend. Are you happy to see more traditional-looking road bikes making a comeback? Do you think the move away from full aero designs is a good thing or a bad thing?
Colnago V4RS might actually have good aero.
You may not be familiar with "D" shaped airfoil profiles were probably first explored in concept almost 20 years ago to be utilized as blade root for those huge wind turbine blades. The main reasoning for this airfoil design is to have the lowest drag in the thickest airfoil geometry possible, thus, achieving significant reduction in blade weight or improved stiffness at less drag penalty.
The idea behind a "D" airfoil is to 'trip' the air flow around the sharp corners in the "D". Tripping the airflow in this controlled fashion creates a more or less neutral pressure pocket of turbulent airflow behind the airfoil (at the flat section of the "D"). This pressure pocket forming behind a D airfoil is higher compared to the turbulent pocket behind a cylindrical or sometimes even traditional aero bike tubes. The higher the pressure you get behind the airfoil, the less drag the airfoil gets.
Additionally, the rough surface finish of V4RS allows the air to 'stick' better and flow around the bike in a controlled fashion. That plus, the turbulent wake behind a D airfoil can further help air flow tighter around components behind it. We do want the turbulent wake to flow behind bike components in a more or less straight direction behind them, not in a wavy manner. Cylindrical tubes and sometimes even traditional aero tubes with smooth finish is notorious for generating wavy turbulent wake and components behind it won't be able to take advantage of the 'draft' components in front of it makes if the 'draft' is fluctuating. A tight and controlled wake of bike components not only reduce drag of the bike but can also reduce drag of the rider!
To put it simply. The size and properties of the airflow wake a bike+rider leaves behind is correlated with its overall aero drag. The smaller and less wavy this wake and the quicker this wake dissipates are good signs of reduced drag.
Another advantage of using D tubes is you can make it stiffer or lighter (at the min UCI weight) compared to a traditional aero tube. So it's definitely a step in the right direction for bikes in aiming for all three factors - aero, stiffness, and lightness.
You may wonder why we don't see it often or not at all in Wind Turbine blades for which they were originally designed for? They make more noise than traditional airfoil shapes. Probably not good for wind farms and it would take a huge expense to upgrade those massive wind turbine blades to D airfoils even if noise isn't a problem.
And why not used in aircraft? Although it's entirely feasible to use a much flatter version of the D airfoil for airplane wings and even the body, D airfoils are not suited for traditional airplane designs. They'd be less efficient and even generate more drag if directly employed in traditional aircraft design. Aircraft designs suitable for D airfoils are pure wings with no body or those with flat lifting bodies with with little or no wings like some space shuttle concepts and indeed some space shuttle concepts have employed D airfoils in one way or another as early as the late 1960's.
It took far too many decades for our bikes to catch up to the tech....but no big deal really as it only makes you marginally faster!
