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Jan 06, 2013 -- On band tension, wire strength, cup shape, and smaller breasts
I measure 27" underbust. That means I'm well within 28 band size territory, possibly even below. Now, apart from the fact that I'm still in the process of getting used to wearing tighter bands, I'm finding that in many of the bras I've tried I end up with the following issue: I get a better SHAPE when I size up in the band, even though the smaller BAND definitely doesn't seem too tight. The tighter band seems to put undue tension on the cups though, resulting in wrinkles, puckers and a flattened shape that aren't remedied by bending the wires or any other trick I've tried to come up with, EXCEPT for wearing it with an extender.
But do I really need looser bands? Doesn't wearing a looser band go against everything proper bra fitting is about? After all, band sizing up, of course, results in a whole host of other fitting issues, from a band that feels slightly looser than I would consider ideal (if it isn't outright riding up), to a centre gore that is not tacking to my sternum as securely as it should (if it isn't outright floating).
I'm trying to understand what is happening here from an engineering point of view ... bear with me
Roughly speaking there are three main 'forces' working in a bra:
(1) bra band tension -- determined by band length and elasticity in relation to body circumference.
(2) the weight of the breasts -- determined by volume, density and breast tissue distribution, as well as breast shape: deeper breasts create a larger momentum than shallower breasts.
(3) underwire 'spring' -- determined by the strength and flexibility of the material.
These three forces should be in balance for the bra to function well, not just in terms of support, but also from the point of view of shaping. So what is going on when I find I get a better shape by band sizing up?
The Usual Suspect: the band is too tight.
What does a too tight band do? A band that is literally too tight for one's body circumference 'springs' the underwires open too much, distorting the cup shape, indeed resulting in a flattened, sub-optimum shape. However, let us assume that the band is actually not too tight for the body, but the cup shape problems still exist. How is that possible?
Suspect #2: the breasts do not provide enough counter balance.
The amount by which an underwire is 'sprung' depends on the band tension on the one hand and the counter weight of the breasts on the other. If the breasts aren't 'heavy' and/or projected enough for the way the bra is designed then the band tension isn't counter balanced by the breast weight and the wires are 'sprung' open too much, again, flattening the cups in the process and resulting in a sub-optimum shape. Now, as breast 'weight' isn't exactly something that can really be changed, what is left?
Suspect #3: the wires are too flexible.
If the breasts, because they are not 'heavy' and/or projected enough, cannot balance out the tension caused by the band, then the wires have to be strong enough to resist the force themselves. Ergo, contrary to intuition, when it comes to SHAPE, smaller cup sizes need LESS FLEXIBLE wires than larger cup sizes in the same design (note that I'm talking about cup shape here, not support!). Of course, cups can be designed to incorporate more wire spring but that would require a completely different approach from what seems to be common practice.
There actually is a suspect #4 as well, I realise as I write this: the amount of elastic pull in the band is too great. In theory a band that is less stretchy though not tighter could solve the problem of too much tension on the wire too, but this would cause all sorts of other issues, the most obviously being wearing (breathing) ease.
If wire strength is taken into account in bra design and manufacturing at all it usually results in more flexible wires being used in the smaller cup sizes. 'Because smaller cup sizes need less support'. But flexible wires do nothing for the shaping of smaller breasts unless an entirely new approach to cup design is adopted too! But that approach would be unnecessarily complicated, wouldn't it? Three variables, two of which can be controlled (band tension and wire strength) and one that would only lead to guess work (breast 'weight') -- it seems to me that better fitting cups that do not flatten smaller breasts are only a 'wire strength' away.
Filed under Boob and body issues
14 comments
I must say, this also goes for bigger sizes too. When I get the time I'll photograph my andorra wire experiments - the cup is the right volume when I bend the wires in the right shape, but they get distorted by the band (that is btw borderline riding up, the wires are that weak) and hello quadboob and empty fabric on the sides.
I wonder though why haven't you taken the straps into account? I would think they do have a role in the forces division? Not a crucial one, but still?
The Andorra has way too flexible wires in my opinion, and by your comment I'm guessing not just in my size. I'm definitely not a fan of too flexible wires IN ANY SIZE, but that is not really the problem I'm trying to address in my little 'novel' above ... I was simply musing about these problems I personally keep encountering considering cup shape -- I may be totally off in my analysis :)
Anyway, the straps as you mention of course also factor in, but for this post I was mostly thinking of the 'horizontal' forces involved. The purpose of the construction of a well-fitting bra is after all to divert as much vertical tension as possible horizontally, relieving the straps of (some of) their load-bearing function. In addition, in smaller cup sizes the role of the straps is much less critical than in the larger cup sizes when it comes to dealing with said load-bearing. For the purpose of this rambling I didn't feel it necessary to go into this aspect as well -- the thing got long enough as it is ;)
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