Q: Why does a luggage zipper burst open under load?
Luggage zippers see loads a garment zipper never sees, so burst-open is often a specification or packing issue before it is a defect. Where the split starts and how the bag was packed decide which explanation fits.
- Note where the split starts: at a corner, at the slider, or along a straight run.
- Check the load, because overpacking puts the chain under tension that pushes teeth apart.
- Inspect the slider gap and the chain size against the maker's specification for the bag type.
- Check the seam allowance at corners, where the tape is often trimmed or stretched.
- Test a sample length of the same chain with a slow pull to see where it separates.
Separation at a corner is usually a sewing or trimming issue, while separation along a straight run under a normal load points to slider gap or chain size. For travel goods, the chain and slider class recommended for the expected load should be confirmed at the design stage, since a garment-grade zipper will not hold a packed case.