Nylon (sometimes labeled as polyamide) is the go-to fabric when durability is your top priority. It's significantly stronger and more abrasion-resistant than polyester, which means it holds up better if you slide out on a trail or brush against branches. That's why you'll see nylon most often in mountain biking jerseys and gear built for rough use.
Beyond toughness, nylon has a noticeably softer, smoother feel against the skin compared to polyester. Many riders find it more comfortable for long days in the saddle. The trade-off is that nylon tends to be slightly heavier and can run warmer, so it's less ideal for hot-weather road riding where maximum breathability matters.
You'll rarely find a jersey made entirely of nylon—it's usually blended with elastane for stretch and shape retention. If you ride MTB, gravel, or just want a jersey that can take a beating, nylon is a smart choice. For road cycling in warm conditions, polyester blends still reign supreme.