Common feature of sandwich structure is a lightweight thick core,included between two thin stiff skins.UD carbon fiber have lower strenth but higher thickness which provides high bending stiffness and an overall low density.
This special structure allows to reduce weight without compromising stiffness, this helps hand-build rims with improved performances.Lighter rim weight results in improved riding handling,response and control,while the wheel stiffness assures a better interaction between the tire and the ground.
As the carbon fiber hold the tension very well,we mix different angles fiber to a uniform material to archieve a stiff enough and strong performance.