A brushed inside is made by raising the fibres of the inner surface of the knit, which traps air and feels soft and warm against the skin. Fleece-lined leggings are popular for cold weather, and the term covers different constructions, from a brushed jersey inside to a bonded lining. The brushing also loosens fibre ends, which can lead to lint, shedding and pilling, and it can change how the fabric stretches. A good specification covers all of these.

Fleece lined leggings: weight and structure

Weight in gsm, measured with ASTM D3776, tells you how substantial the fabric is, but it is not the whole story. Ask for the fibre content of face and back, the knit structure, brushing level and finished thickness. A fabric with a heavy brush can feel warm but add bulk at the seams and under clothes. Compare two or three constructions in wear.

Stretch, recovery and opacity

Leggings are stretched in use, and a heavily brushed fabric can lose recovery or become see-through when stretched, especially in light colours. Test stretch and recovery with a method such as ASTM D4964 for elastic fabrics, before and after washing, and check opacity by stretching the garment over a form or on a wearer under bright light.

Pilling and shedding

Test pilling on washed fabric with a Martindale method such as ISO 12945-2 or ASTM D4970. Wash several samples and check the washing water and the dryer lint trap for fibre. Compare against another brushed fabric you have used before, so you have a reference.

Washing and drying

Wash samples with a named procedure such as ISO 6330 and check shrinkage, surface appearance and loss of softness. Heavily brushed fabrics can mat if dried too hot, so choose the drying instruction on the evidence. The FTC Care Labeling Rule, 16 CFR Part 423, requires a reasonable basis for the instruction.

What to write in the spec

Write weight, thickness, brushing level, face and back fibre, stretch and recovery, pilling limit and the wash and drying instruction. Keep a washed approved sample and compare each bulk lot against it. Brushing is also a process step, so ask the mill to state the brushing passes and the machine settings it used on the approved lot, and to hold them for repeat orders; a small change in brushing can change warmth, shedding and the stretch of the finished legging more than a change of yarn supplier would.