Which is stronger, nylon or polyester?

Nylon is generally stronger and more abrasion-resistant for its weight, which is why it is preferred for backpacks, ropes, and gear that takes mechanical stress. Polyester is still strong but trades a little strength for better UV and color stability.

Polyester. It absorbs almost no water, so it dries faster and is less prone to water spotting. Nylon absorbs slightly more moisture and dries a touch more slowly, though both are far quicker to dry than cotton.

Why does outdoor gear use polyester so often?

Because polyester resists ultraviolet light better than nylon, holds its dyed color longer in the sun, and dries quickly, all of which matter for clothing and equipment left outdoors.

Side by side

Nylon vs Polyester

Nylon and polyester are the two great synthetic fibers, both spun from petrochemicals, both strong, light, and quick-drying. The differences are matters of degree. Nylon is stronger, more elastic, and softer, with a slightly silkier hand, but it absorbs a little more water and is more sensitive to sunlight. Polyester is more resistant to UV, holds dyed color and shape better, dries faster, and costs less, which is why it is the more common of the two.

Nylon

No. 121

woven or knitted from polyamide filament · first documented 1938

Polyester

No. 122

woven or knitted from PET filament or staple · first documented 1941

The differences

Aspect	Nylon	Polyester
Strength	The stronger and more abrasion-resistant of the two; very tough for its weight.	Strong, though generally a step below nylon in tensile strength.
Stretch and hand	More elastic and softer, with a smoother, more silk-like feel.	Less stretchy and a touch crisper to the hand.
Water and drying	Absorbs slightly more moisture; dries fast but a bit slower than polyester.	Absorbs very little water; dries fastest and resists water spotting.
Sunlight and color	More prone to fade and weaken in prolonged UV.	More UV-stable; holds dyed color and shape better outdoors.
Cost	Generally more expensive.	Cheaper, and the most-produced fiber in the world.
Best for	Hosiery, swimwear, backpacks, ropes, anything needing strength and stretch.	Everyday apparel, outdoor and performance wear, anything left in the sun.

Which to choose

For sheer strength, stretch, and a softer hand, nylon leads, which is why it dominates hosiery, packs, and gear under load. For UV resistance, color retention, fast drying, and low cost, polyester wins, which is why it is the default fiber of mass-market and performance clothing alike.

Common questions

Which is stronger, nylon or polyester?: Nylon is generally stronger and more abrasion-resistant for its weight, which is why it is preferred for backpacks, ropes, and gear that takes mechanical stress. Polyester is still strong but trades a little strength for better UV and color stability.
Which dries faster?: Polyester. It absorbs almost no water, so it dries faster and is less prone to water spotting. Nylon absorbs slightly more moisture and dries a touch more slowly, though both are far quicker to dry than cotton.
Why does outdoor gear use polyester so often?: Because polyester resists ultraviolet light better than nylon, holds its dyed color longer in the sun, and dries quickly, all of which matter for clothing and equipment left outdoors.

Full entry: Nylon Full entry: Polyester

Sources & References

1.Nylon, Wikipedia
2.Wallace Carothers, Wikipedia
3.Polyester, Wikipedia
4.Polyethylene terephthalate, Wikipedia