Most people assume roll-down is about their body shape. It is not: it is a construction question, with three specific causes.
Cause 1: a single-layer band
The cheapest solution is for the maker to fold the fabric edge over and stitch it. That fold holds no shape: as soon as the belly engages, the top edge turns outward, and from there it rolls on its own.
How to spot it: pinch the top of the band and bend it. If you feel a single thickness, it is single-layer. A double-layer band is noticeably stiffer and will not crease sharply.
Cause 2: the band sits too low or too high
There is a point on the torso that moves least when you fold: just below the rib cage, above the navel. If the top of the band falls below it, it slides over the belly and turns down. If it reaches above it, it tightens on the rib and slips from there.
How to spot it: put them on and fold forward. Look at where it creases. If the middle of the band creases, it is in the right place; if the top edge does, it is not.
Cause 3: too small a size
This is the surprising one, because instinct says the opposite. A tighter band does not hold better — it rides up onto the rib, exactly where movement is greatest during breathing, and rolls there.
How to spot it: if the band leaves a mark on your ribs but not on your hips, it is too small.
What you can do
If you already own them: fold the band down and wear it turned over — the double thickness will then hold. It works, but it makes the cut look shorter. The alternative is a high-waisted top or bodysuit that holds it in place.
If you are buying now: a double-layer band above 10 cm essentially solves the problem. Ours is 12 cm and double-layered — not because it sounds good, but because the sixth prototype showed that 9 cm still rolled.
One thing that does not help: a silicone grip strip inside the band. That works against slipping down, not against rolling — they are different problems.
