Not all power bars are created equal: which patterns will give you the best side support, and why

Why do some power bars fit snugly into lower cups and some don't?

If you have ever made a bra with a power bar or attempted to add a power bar to a bra yourself, you may have noticed that not all power bars behave the same way. Some push your breasts forward nicely, while others don't seem to be very "powerful" and instead result in quite a rounded outer cup. But which bras will do which? Is there a way to tell before sewing the bra together? Yes!

An extended version of this post is available now on my ko-fi to read for just $3/£2. You can also choose to subscribe monthly for future access to extended posts, extra content, and to support my work. 


diagram of a bra from the front, showing one side as narrower/more side supported than the other

The power bars in bras like the Pin-Up Girls Shelley, and in the B,Wear Margareta, are quite different to the ones found in ones like the Lilypadesigns Labellum and Lanai. With this simple method, a quick inspection of the lower outer cup and power bar pieces will tell you how rounded the outer lower cup will be when worn. 

Using two examples - the Margareta vs the Labellum, we will lay the pattern pieces out and align them where the top of the lower cup meets the power bar. 

Side-by-side of the power bars and lower cups of the Margareta and the Labellum. The Margareta's lower cup fits into the power bar, but the Labellum does not, leaving a gap between the wireline seams
The curve of the Margareta's seam may be confusing, but know that the middle lower cup piece has a concave curve too so they fit together exactly.

You can see that the Margareta's lower cup fits into the power bar perfectly, so these pieces act as one when sewn together - essentially, there is no shaping here the seam in this region is decorative (providing some structural support in the stitching). The Labellum has an opposing curve - the pieces don't fit together when laid out, and when the top of the lower cup is placed against the power bar you can see a gap at the bottom. The pieces have to be sewn together to fit, creating a three dimensional shape.

This is the key to their differnces in fit- the Labellum's power bar curvature causes additional roundness in the lower cup. 

Being able to recognise this difference should allow you to better pursue a bra shape that suits your preferences. In my experience, this added roundness to the outer region of the cup causes a more "relaxed" silhouette when viewed from the front, while the non-curved power bars create a strong side support that lends itself to a narrow shape when viewed from the front, and more projection when viewed from the side. 

Curvature Amounts - what's best? Is there a middle ground?

It's really up to you which type of power bar you prefer. Those who enjoy the strong shaping of Polish bras will probably do better in power bars with no added roundness. Those who prefer a more "natural" style. From what I have seen of the Labellum and similar patterns with large curves, there is a noticeable degree of outer cup roundness when worn and I personally would say that the resulting bra is not a super fashionable shape. It's not within my preference but it might be yours - sometimes a lot of side support can cause an over-projected shape that may make your breasts more prominent than you would like, compared to the more natural shape of a more rounded outer lower cup.

The Josey Plus pattern laid out as above, showing a gap between the wireline seams that is smaller than that of the Labellum
The angle formed by drawing the top of the lower cup to the wireline is much smaller here than it is for the Labellum above, but it is not zero as it is for the Margareta.

Some bra patterns - namely Willowdale and Josey/Josey Plus - feature a small curvature in the lower outer cup. When the cup pattern pieces are laid out, there is a gap to be found between the wirelines of the lower outer cup and the power bar but this gap is much smaller than the other bras mentioned. 

I have also noticed a similar pattern when taking apart popular ready-to-wear patterns like the Panache Envy. Given my experience with the Envy in a lot of sizes, I think that having some curvature here can help with adding just a little space to the lower cup to help with roundness, while still having the advantages of a supportive power bar. Additionally, adding a no-curvature power bar, reinforced with stitching to prevent stretch when the rest of the cup fabric is a little stretchy may cause this region to wrinkle a bit. So having a bit of curve might be helpful to prevent creases there. 

What other things can impact the performance of a power bar?

Lots of bra makers have fitting troubles with the outer portion of their bra cups, and power bar/lower cup curvature is only one piece of the puzzle. Other issues, like poor band/cradle/wire fit, wire width, apex position, and strap position all have an impact on the appearance of the bra and the support found in this area.

How can I tell what the power bar shaping will be before I have purchased a pattern?

Aside from inspecting other people's makes/the promotional images, there's not an easy way to tell from the information given out pre-purchase. So thanks to my instagram followers who dutifully sent me pictures of their patterns, I have collated a list of bra patterns with power bars and if they fit perfectly (no added roundness), have a small gap (a small amount of added roundness), or a large gap (lots of roundness) between the pieces. 

Some data is missing from certain size sets (and some entire bras - the PUG Judy and the Bravo #2 by Bravobella), please send an instagram DM if you can contribute!)

This section is not a review or dis/endorsement for any of the below patterns, so understand that other shaping issues may be present.

No added roundness (0 degrees dart angle)

Annie and Myras - Bette Bra (30D-38G)
B,Wear - Margareta  (70-105 A-I) - No gap in 70-85 A-I size set, no data for others.
Orange Lingerie - Marlborough (30A-40DD, 30DDD-40J) - No gap in A-DD size set, no data for others)
Pin-Up Girls - Shelley (30AAA- 48H) 
Pin-Up Girls - Judy (30AAA-48H) - Not tested but I understand it uses the same cups as the Shelley

Slight added roundness  (<5 degrees dart angle)

Cashmerette - Willowdale (28C - 54J)
La Bella Coppia - Josey (30H - I, 32 G - I, 34DDD/F - J, 36DD/E - I, 38D - H, 40C - G, 42D - 42F) 
La Bella Coppia - Josey Plus (34K-N, 36J-M, 38 I-L, 40H-K, 42G-J, 44DDD/F-I, 46DD/E-H) - A little more added than the standard Josey
(Upcoming) Van Jonsson Design - Ever (30C-36FF, 28D-34G)

Considerable added roundness (5+ degrees dart angle)

AFI Atelier - Afi Exquisite (60-110 A-I) - Large gap in 60-85 E-I, no data for others.
Cashmerette - Loftus Bralette (28C-54J). Note: large gap present but internal stretch sling that covers this seam is included which will have an impact on shaping
Lilypadesigns - Labellum (30-42 DD-GG, 28-44 GG-KK).
Lilypadesigns - Lanai  (28-44 A-DD, DD-GG, GG-KK). Note: large gap present in all size ranges but optional non-stretch sling that covers this seam is included, which will have an impact on shaping.

Extension: Another way to look at power bar shaping, excess power bar length, and directing this excess length.

The extended version of this post is available to my supporters on ko-fi to read for just $3/£2. Thank you to all my supporters!