the armhole problem — why most tanks don't fit us.

the tank fits in the dressing room. you buy it. you wear it to the gym. third set of overhead press, the armhole has worked itself into a diagonal fold against the side of your chest and every rep is pinching. same tank, two different environments. the brand tested it on a mannequin that doesn't lift. we took five competitor tanks apart — literally, seam-rippered them down to panels — and we figured out what they all got wrong.

// 02the four things every competitor got wrong

armhole set too high. four out of five competitors had the armhole top seam 1.5-2 cm above the natural axilla. means any lateral shoulder movement pulls the seam directly into the armpit — which, if you're wearing a binder underneath, means the seam is pressing down onto the top of the binder band. this is the armpit-chafe moment.

armhole cut too shallow at the side. three out of five. the armhole depth [vertical drop from shoulder to under-arm] was 22-24 cm. for a transmasc body, 26-27 cm is correct. the extra depth gives the chest panel room to move independently of the shoulder.

side seam straight. every single one of them. a straight side seam means the tank pulls in at the waist [if you have a taper] or balloons out [if you don't]. the correct shape is a shallow-S — wider at the chest, slight curve inward at the lower-rib, straight from the waist down.

no bonded seam at the armhole. every competitor used a stitched seam. stitched seams have zero give in the direction perpendicular to the stitch line. means the moment the shoulder pushes out, the seam takes 100% of the force. bonded seams distribute it across the whole panel.

i have been buying tanks for fifteen years and have never once gotten the armhole right. i thought that was my body. it was not my body. — fit notes · customer interview · 2025-11

// 03the pattern we re-drafted

our current tank pattern — across the ibiza, stockholm, and london colorways — uses a 26.5 cm armhole depth, a 1.2 cm lower armhole top seam, a shallow-S side, and a bonded armhole seam. the chest panel is drafted at 3/4 volume [between women's and men's standard], which was covered in patch notes 001.

[reference tank] · ibiza black

the ibiza tank

the pattern above, applied. 26.5 cm armhole, bonded seam, shallow-S side. the tank every other SBA tank is drafted from.

$35 · FIRSTCLASS10 → $31.50

shop tank

// 04the test we run before shipping

every new tank pattern now runs through what we internally call the overhead-press test. three lifters, three sets of ten overhead press at bodyweight, tank on over a binder. if the armhole works it's way into a diagonal fold at any point, the pattern gets sent back. we've rejected four pattern drafts in the last twelve months because of it.

next issue · 003 · the shorts that stay down at the squat rack