Elastic and Hardware Sourcing for Sports Bra Production
Elastic and hardware are a small share of unit cost and a large share of performance. The underband in a medium impact bra does most of the support work, the hook closure sets how that band is tensioned, and the strap elastic determines whether a racerback stays put during rowing or cycling. Yet these items are frequently specified as a width and a colour, which leaves the mill and the factory to decide everything that actually matters.
Elastic Types in a Medium Impact Bra
Three categories are typically used. Underband elastic, usually 30 to 50 millimetres wide, carries the load and is often a plush-backed or velvet-finish band for comfort against skin. Strap elastic, typically 10 to 20 millimetres, must resist rolling and stay flat. Edge elastic, such as picot or folded binding, finishes the neckline, the armhole and the cut-out opening.
For the band, specify whether it is a knitted or woven elastic. Woven elastics are firmer and recover better but have less stretch; knitted elastics are softer and stretch further but can grow over time. The right choice depends on the support level you are targeting and on how much of the support comes from the shell fabric.
Specifying Elastic Performance
Width and colour are not a specification. Ask for modulus, expressed as the force required to reach a defined extension, commonly 30 or 50 percent, and for recovery, expressed as the percentage return after extension and a defined hold time. A reasonable expectation for a band elastic is better than 90 percent recovery after extension and repeated washing.
Request wash durability data, and require colour fastness to water and perspiration under the ISO 105 series. A dark band that crocks onto a light shell during wear is a defect that only appears after the customer has worn the product.
Hook-and-Eye Hardware
Specify row count, hook count per row, hook gauge, backing tape width and coating. A three-row closure with two or three hooks per row is standard for medium impact, because it gives the wearer adjustment range and keeps the band stable. Coated steel hooks are common; nylon hooks are lighter and quieter but wear faster.
Require a nickel-free declaration and testing where relevant. Nickel release from metal components in prolonged skin contact is restricted under the EU REACH regulation, with EN 1811 as the reference test method for nickel release. For the US market, confirm CPSIA applicability for the product category.
Rings, Sliders and Adjusters
If the design uses sliders or rings, specify material, finish, plating thickness and a pull test value. Coated metal is generally better for wash durability than plastic at this price point, but it needs a coating adhesion test. Keep hardware off the centre back where it will sit under a racerback convergence point and press into the spine.
Minimums and Lead Time
Plan for elastic minimums of 1,000 to 3,000 metres per width and colour, with lead times of 20 to 35 days. Hook-and-eye tape commonly carries a 500 to 1,000 set minimum and 25 to 40 days; customised widths or branded finishes can push minimums to 5,000 sets. Custom coloured elastic to match a shell fabric is possible but adds a dye lot and should be booked with the fabric, not after it.
Book all of it against the confirmed bill of materials. A late change from a two-row to a three-row closure is one of the most expensive small decisions in bra development.
Qualification Before Bulk
Approve a physical sample of every elastic and hardware item, attach it to the sealed pre-production sample, and keep both. On repeat orders the factory may substitute an equivalent; without a reference you have no way to detect it, and equivalent is rarely the same in recovery.
