FIRST LAYERS AND THERMALS

Women's MTB First Layers & Thermals: Base Layers by Fox

First layers and thermals are the garments you wear directly against the skin, underneath your jersey, shorts or trail trousers. This women's category at Foxracing.si brings together short- and long-sleeve base layer tops, thermal bottoms and liner shorts for mountain biking, from warm summer rides to cold winter trail days. It is for female riders who want moisture management in the heat and an extra layer of warmth when temperatures drop.

What this category covers

• Short-sleeve and sleeveless base layer tops – lightweight next-to-skin tops that move sweat away from the body in warm weather and stop a wet jersey from sticking to your back.
• Long-sleeve thermal tops – brushed or warmer knit fabrics that add insulation for autumn, winter and early-season rides, worn under a jersey or jacket.
• Thermal bottoms (long underwear) – close-fitting leg layers worn under shorts or trail trousers to keep the thighs and knees warm without adding bulk.
• Liner shorts with a chamois – padded undershorts worn beneath baggy MTB shorts for saddle comfort on longer rides.

How to choose a women's base layer

• Fit: a first layer should sit snugly against the skin so it can wick moisture. A loose base layer holds sweat and stops working. Check the size chart on each product rather than assuming your jersey size.
• Fabric: synthetic knits dry fast and are easy to care for, while merino and merino blends stay warm when damp and resist odour on multi-day trips.
• Warmth level: pick a thin, open-knit layer for summer and a thicker, long-sleeve thermal for cold and wet conditions. Many riders keep one of each.
• Seams and edges: flat seams and bonded hems reduce rubbing under a pack, body armour or a chamois.
• Chamois choice: if you ride longer distances, look at liner shorts with a padded insert; for shuttle laps and short trail rides an unpadded layer may be enough.
• Layering: plan the first layer together with what goes over it, so the whole system breathes instead of trapping sweat.

Brands

This category is dedicated to Fox, whose women's mountain bike range includes next-to-skin tops, thermal layers and padded liner shorts designed to work with Fox jerseys, shorts and protection.

FAQ

Do I really need a base layer for mountain biking?

It is not compulsory, but a first layer keeps sweat off your skin, which means less chilling on descents and less friction under a backpack or knee and elbow protection.

Merino or synthetic for a women's base layer?

Synthetic fabrics dry quickest and suit hard, sweaty efforts, while merino blends insulate even when damp and stay fresher over several days, which makes them popular for cold-weather and multi-day riding.

What do I wear under baggy MTB shorts?

Most riders use liner shorts with a chamois for saddle comfort; in cold weather you can add thermal bottoms over or under the liner, depending on how much warmth you need.

Can I wear a thermal top on its own?

A long-sleeve thermal works as a standalone top on cool, dry rides, but it is designed as part of a layering system, so add a jersey or jacket when it is wet or windy.

How should I wash first layers and thermals?

Always follow the care label on the garment; technical knits and merino generally prefer cool washes and no fabric softener, which can coat the fibres and reduce wicking.

Browse the women's first layers and thermals and build a layering system that works from summer trails to winter rides.