Originally Posted by
Maelochs
And when they climb HC mountains on hot days they open their jerseys. Horrors!!!! The massive aero drag!!!!!!!
It's obviously less of an issue at slower speeds, like when climbing and/or when the need to dissipate heat is greater, but yes, open and unzipped jerseys are a massive aero drag. IIRC, once
RChung measured the drag of his partially unzipped jersey, he made a point of no longer partially unzipping his jersey.