Most TT's and triathlons take place anywhere from late spring through early fall, often on some of the hottest days of the year. A TT/tri-specific lid can certainly speed up your ride, but not if it isn't built with enough ventilation to keep you cool. How to make "aero" helmets that save watts...

It's still built around the same values: aerodynamic and ventilation. The narrow droplike shape and small frontal area provide the most aerodynamic shape, while the dimpled rear surface helps traps air pockets to improve the airflow over and around the helmet. Everything combined creates a helmet...

We'll be the first to admit that, over the course of long time trials or triathlon rides, we don't maintain an ideal TT position. This isn't just the rider's fault though, as our yaw angle also changes based on wind conditions, turns in the course, changes in gradients--in short, the dynamic...