Size Set and Fit Approval Process for Bulk Sports Bra Orders

The size set is the last document-based control before several hundred or several thousand units become your inventory, and it is routinely approved in ten minutes with a tape measure and a phone photo. That is how a brand ships a run that fits at M and gaps at XS. For a medium impact bra, where the underband carries the load and the racerback geometry sets the strap path, a size set is a data collection exercise, not a formality.

Which Sizes to Request

Request the base size, the smallest size and the largest size at minimum. For a B/C cup block running S to XXL, that means S, M and XXL. If your volume is concentrated at the top of the range, add the second largest size as well. A size set of three to five pieces costs far less than the rework or the return rate it prevents.

Where the range spans two cup blocks or a plus extension, treat each block as a separate size set. Blocks grade independently and one does not validate the other.

Measurement Points That Matter

Measure underband relaxed length, underband stretched length at a defined pull, cup width and depth, wing height at the side seam, strap length from the convergence point to the band, hook overlap on each row, and cut-out position relative to the band and neckline.

Two of these do most of the work. Underband tension drives almost every support complaint, and cut-out position drives almost every comfort complaint. If the cut-out has drifted toward the shoulder blade at the size extremes, the grade is wrong even if every other measurement passes.

Workable Tolerances

Use percentage-based tolerances for stretch dimensions and millimetre tolerances for fixed components. A reasonable starting point: underband relaxed plus or minus 2 percent, underband stretched plus or minus 3 percent, strap length plus or minus 5 millimetres, elastic width plus or minus 1 millimetre, hook overlap plus or minus 3 millimetres, and cup dimensions plus or minus 3 millimetres.

Tolerances tighter than these are achievable but will be priced in, and tolerances looser than these will show up in your returns data. Agree the numbers before the size set ships, not after it arrives.

Approval Protocol

Fit each size on a live model whose measurements match your graded spec. Document the result with measurements, dated photographs and a written approval or rejection per size. If a size fails, reject the whole set and request a corrected round rather than approving conditionally; conditional approvals are the ones that get lost between the sample room and the cutting floor.

Seal an approved reference sample per size and keep it for the life of the program. When the second order lands eight months later, that sealed sample is the only reliable comparison you have.

Failure Points to Check First

Band tension drift across sizes is the most common defect: the grade adds length but the elastic modulus stays constant, so the smallest size feels tight and the largest feels slack. Cut-out migration is second. Pad pocket rotation is third, and it is invisible on a flat table but obvious once the bra is worn.

Confirm that the removable pads sit flat with no edge curl, that the hook closure aligns without the band twisting, and that the strap convergence point still sits in the same relative position across all sizes. Then release bulk with a written sign-off referencing the sample date and revision number.