Which zipper works on a tent door?

Q: Which zipper works on a tent door?

A tent door uses a size 5 or size 8 coil, two-way, with two sliders so the door can be opened from the top or the bottom. The size 8 is the better choice on a large door or a vestibule that is opened and closed many times, because the heavier chain resists spreading when the fly is tensioned. Sew the zip with a little slack along its length, and keep the tape covered by the fly so rain does not run directly onto the teeth.

• Size 5 for a small door; size 8 for a large door or vestibule.
• Two-way with two sliders.
• Sewn with slack, and covered by the fly.

The common pitfall is a zip pulled tight around a corner: the chain cannot bend and the slider jams halfway up the door at the worst possible moment. The second is sand and grit, which work into an unprotected coil and grind the slider. Specify a coated tape, keep the fly overlap generous and check the door on a pitched tent rather than on a flat table.