Castelli's Fast Feet project: aerodynamic foot coverings for every condition. The TT shoecover is designed for maximum aerodynamics in time trialing, within the limits of the UCI rules. Castelli’s designers developed it through CFD analysis followed by extensive fabric and on-bike wind tunnel testing. The smooth silicone-coated foot portion smooths out the shape of the foot, while the grooved leg portion helps detach the air as it flows around the leg. The shoecover is cut high, reaching to the calf. There's no reason not to wear it on the road, but its gains are maximized at TT speeds.
Castelli's Fast Feet project – for road riding in warm conditions
The sock portion is based on a normal sock for in-shoe comfort
The leg portion is constructed with engineered grooved Lycra® to help detach airflow