Carry less, better
Zipper Quality in Bags
Gauge, tape, and the stopper matter more than the logo on the pull. #5 for pockets, #8 to #10 for the mouth of a work bag.
Updated 27 Aug 2026 · 6 min read · zipper quality in bags
Gauge is the size of the tooth
#3 is a trouser zip. It does not belong on a 4kg tote mouth. #5 is pockets and lining. #8 is a normal backpack main. #10 is heavy luggage. The number is approximately the tooth width in millimetres. A chunky metal fashion zip can still be a weak #5 with a big pull.
Coil (spiral nylon) bends and is repairable. Vislon (moulded plastic teeth) is snag-resistant on outdoor packs. Metal looks right on leather and can lock if a tooth bends. Each can be excellent. Each can be junk.
Tape, stitch, and the slider
The cloth tape should be woven tight and stitched with a zipper foot, not a wandering topstitch 4mm away. Double sliders on a work bag let you open a gap without opening the mouth. A locking slider helps on backpacks.
| Use | Gauge | Type that usually wins |
|---|---|---|
| Lining pocket | #5 | Coil |
| Tote / briefcase mouth | #8 | Metal on leather; coil on nylon |
| Backpack main | #8–#10 reverse coil | YKK-style reverse coil |
| Duffel 50L+ | #10 | Vislon or metal |
| Fashion novelty zip | Unknown | Assume #5 and a weak slider |
Failure, repair, fakes
Split coil often means a worn slider, $15–$25 to replace the slider if the teeth are intact. Missing metal teeth means a new zip. Do not force a stuck zip with pliers; you will eat the tape. A drop of zipper lubricant beats oil from the kitchen.
On leather work bags the zip is the moving part that dies while the hide still looks fine. That is why nylon versus leather is also a zipper conversation: nylon packs are built around replaceable zips. Logo pulls on counterfeits are loud and light.
Questions, answered
- Is a metal zipper always better?
- No. Metal looks right on a briefcase and can snag knit lining. Reverse-coil is better on a rain pack. Gauge and slider quality first.
- Why does my zipper separate behind the slider?
- Worn slider. The teeth are probably fine. Replace the slider before you replace the whole zip.
- Can I grease a zipper with olive oil?
- No. It stains tape and lining and gathers grit. Use a zipper lubricant or a tiny bit of paraffin on the teeth, then wipe the excess.
