Chaussettes Vélo Castelli Sweetspot 20 Thermal

PrimaLoft yarns

PrimaLoft is a synthetic insulating material that traps air between the fibres, providing warmth without the bulk of natural insulation such as down. At the same time, it wicks moisture away from your skin to the outside of the sock, so your feet don’t feel clammy when you start to sweat during exercise.

Why does this work better than a standard woollen cycling sock?

A standard woollen sock also retains heat, but becomes heavy and slow to dry once it gets damp. PrimaLoft fibres were developed as a synthetic alternative to down: they still provide insulation when wet, dry faster, and retain their shape and thermal properties after washing. This is important for a bike sock, as your foot quickly starts to sweat inside a closed shoe, even when it’s cold outside. The material actively wicks away that moisture rather than trapping it, which makes the difference between cold, clammy feet and dry, warm feet after two hours of biking.

Medium-weight construction

This sock is thick enough to provide warmth, but thin enough to fit comfortably inside your cycling shoe without adding extra bulk or creating pressure points.

Do I need to go up a shoe size for this sock?

No, that’s usually not necessary. The medium-weight design is specifically intended to ensure the sock stays within the standard fit of a cycling shoe, unlike thick winter socks which often do require an extra half size. If you’re still unsure, try the sock on with your cycling shoe before planning a longer ride, especially if your shoe is already a bit on the tight side.

20 cm cuff

The higher cuff covers a larger part of your lower leg than a short ankle sock, providing extra protection against the cold.

Why is the cuff height relevant to warmth?

In cold weather, you lose heat not only through your foot, but also through the section of your lower leg between your trouser leg and your shoe. With a short sock, that area remains uncovered, especially if your trouser leg rides up whilst biking. The 20 cm cuff bridges that gap and also works well with a raw-cut or grip finish on a bib tights or leg warmer worn over the top.

• Cooler rides in autumn and winter
• Pair with overshoes or leg warmers for extra warmth

• Warm summer rides: a thin, breathable summer sock is more comfortable for this

• Wash the socks at a maximum of 30°C, inside out, so that the PrimaLoft material retains its thermal properties
• Leave them to air dry: the tumble dryer damages the fibre structure
• Put the socks on and take them off carefully to prevent holes forming at the seams