We’ve always engineered our aero bikes using the lowest drag tube shapes we know of. But the lowest drag bike is more than low drag tube shapes. During the years we spent developing the P4, we also considered the aero interaction of the various tubes with other parts of the bike. The result is Cervélo’s AeroZone engineering principle.
The downtube AeroZone includes nearby components, such as the front brake, fork and wheel. Dropping the down tube “hides” the down tube in dirty air, reducing the high pressure normally found on the down tube’s leading edge, and eliminates the low pressure air that normally pulls rearward on the fork crown.