A wide back band spreads the weight of your breasts over a larger area instead of cutting into one narrow line. The band does most of the work in a bra; your straps are only meant to stabilise. If a bra sits unpleasantly, the cause lies far more often in the band than in the straps.
Why does the band carry, and not the straps?
Your straps run over two small patches on your shoulders. Any weight that lands there lands on a few square centimetres, and you feel that within a couple of hours. The underband runs all the way around your ribcage and so has many times more surface area. The wider that band, the more of the weight ends up there and the less you have to tighten your straps.
That is also why tightening the straps rarely helps: you move the problem to your shoulders rather than solving it. See also bra straps digging into your shoulders.
Why does a narrow band curl up?
A narrow band has to deliver the same tension across less material. That only works with more elastic and more pressure per centimetre, and that is exactly the recipe for two complaints: a red mark at the end of the day, and a band that rolls itself up into a cord. Curling is therefore not a quality problem with the fabric but a physical consequence of too little width.
A wide band that stays lying flat rests against your skin across its whole surface. So there is no edge that can fold over and no single line where all the pressure comes together. More about that in red marks from your bra.
How do you check whether your band sits well?
- The lift test. Raise your arms straight up. If the band rides up with them, it is too loose. A good band stays in place.
- The level test. Look at your back in the mirror. The band should run horizontally, not slope up towards your shoulder blades.
- The two-finger test. You should be able to slide two fingers flat under the band. If a whole hand fits, it is too loose; if nothing fits, too tight.
- The strap test. Slide your straps off your shoulders and let the bra hang on the band alone. If everything stays roughly in place, your band is doing the work as it should.
Too loose or too tight: which way are you wrong?
Most women wear a band that is too loose and compensate with tightly pulled straps. If you recognise that, go one band size down and one cup size up: that is the same cup volume with a firmer band. If you fall between two sizes, read bra intermediate sizes.
If the band cuts in while staying in place, then the size is not the problem but the width. A wider band in the same size solves that without your having to go looser.
What we do
The Luma Contour and the Luma Forma Bra 2.0 both have a wide, circular-knitted underband with no fastening. No hooks also means no bump on your back and nowhere for the band to start folding. The Forma additionally has side reinforcement for anyone who wants to hold more shape.
Both come with 14 days to change your mind, because whether a band sits well is something you only notice after an ordinary day, not in a fitting room. If you are not sure of your size, start with the size finder.
Read on
- How should a bra fit? The 5-point check
- Bra pressing on your ribs? Causes and solution
- A bra that does not pinch: why yours does and what helps
- What is a contour bra?
Frequently asked questions
Why is a wide back band better?
Because the band carries most of the weight, and a wider surface spreads that same load over more skin. Nothing cuts in, you can set your straps less tightly, and you are less likely to get a red mark.
Why does my bra band curl up?
Curling is almost always caused by a band that is too narrow or one that sits too loose. A narrow band has to deliver the same tension across less material and folds over as a result. A wide band lying flat cannot do that.
How do I know whether my underband sits well?
Raise your arms straight up: if the band rides up with them, it is too loose. You should be able to slide two fingers flat underneath, and in the mirror it should run horizontally across your back.
Should I tighten my straps if my bra sags?
No. If your bra sags, your band is doing too little. Tightening the straps moves the weight to your shoulders and causes pain there. Go one band size down and one cup size up instead.
