Modern jockey silks are made from synthetic performance fabrics — most commonly polyester or a polyester-spandex blend — not actual silk. Real silk hasn't been standard for decades. Today's materials are chosen for weight, breathability, rain performance, and how closely they hold to the body at speed.

The name is a holdover. Early racing colors genuinely were silk, which was the lightest strong fabric available at the time. It was also expensive, slow to dry, and prone to tearing. As synthetics improved through the twentieth century, the sport moved on and kept the word.

What's actually used today

Polyester. The workhorse. Lightweight, holds color extremely well through repeated washing and sun exposure, dries fast, and resists the fading that ruins bright colors. Most silks you see on a race card are some form of polyester.

Polyester-spandex (poly-spandex). Polyester with a small percentage of elastane blended in. The spandex gives the fabric stretch and recovery, which means it can be cut closer to the body without restricting the rider. This is what we make our silks from.

Nylon. Occasionally used, particularly in older sets. Strong and light, but generally worse than polyester at holding dye over time.

Real silk. Essentially gone from competition. You'll still see it in framed display sets, historical collections, and the occasional ceremonial piece.

Why fabric weight matters

Silks are measured in GSM — grams per square meter. Lower numbers are lighter.

Lighter fabric is generally better on the track: less weight, less bulk, faster drying. But go too light and the fabric becomes sheer, colors look washed out, and seams start pulling. There's a floor below which a set won't survive a season.

Heavier fabric is more durable and gives deeper, richer color, at the cost of breathability and drying time. It also holds more water in the rain, which is the real penalty.

The practical target is the lightest weight that still delivers full color saturation and holds its seams through a meet. That's a narrower window than it sounds, and it's most of what separates silks that look sharp in September from silks that look tired.

Breathability

A jockey in a race is working extremely hard for two minutes, often in summer heat, wearing a helmet, a safety vest, and boots. The silks sit over all of it. If the fabric doesn't move air and wick moisture, the rider is carrying heat they can't shed.

Two properties matter here and they're different:

Breathability is air passing through the fabric. Wicking is moisture pulled off the skin and spread across the surface to evaporate. Polyester is naturally good at wicking — it doesn't absorb water into the fiber the way cotton does, so sweat moves to the outside and dries rather than soaking in and sitting there.

This is also why cotton never became a silks fabric. It absorbs, gets heavy, stays wet, and clings.

Rain performance

This is where fabric choice shows up most visibly.

A set that soaks through gains weight — not a lot in absolute terms, but any added weight is unwelcome in a sport that measures in pounds. It also clings and flaps unpredictably, and colors go dark and lose contrast, which is exactly when you most want your horse identifiable.

Synthetics handle this far better than natural fibers. Polyester takes on very little water into the fiber itself, so most of what it carries is surface water that sheds and dries quickly. The difference between a good and a mediocre set on a sloppy track is mostly about how fast it releases water and how well it holds its shape while wet.

Cut and aerodynamics

Fabric is only half the story — how the set is cut matters as much as what it's made of.

Traditional silks are cut loose. At 35 miles an hour, loose fabric catches air and billows, which creates drag and, just as importantly, noise and distraction for the rider. Watch a head-on replay of an older set and you'll see the body of the silks inflating behind the rider like a sail.

Our silks are cut aerodynamically in breathable poly-spandex, specifically to avoid that. The stretch in the fabric allows a closer fit that follows the rider's position without restricting the shoulders or the reach forward in the irons — a closer cut in a non-stretch fabric would just bind. The result is a set that stays against the body in the run rather than filling with air.

Why a rider notices

Jockeys don't usually talk about silks unless something's wrong, and when they do it's one of these:

• Heat. A set that doesn't breathe on an 88-degree afternoon at the end of a long card.
• Billowing. Fabric catching air and cracking behind them at speed.
• Restriction. A set cut too tight across the shoulders, which is the one thing worse than a set cut too loose.
• Fit. Silks are made to a size, and a set cut for a 112-pound rider doesn't sit correctly on a 122-pound rider. Too big billows; too small restricts.

Getting fabric and cut right doesn't win races. But it removes a category of small annoyances from a rider who has enough to think about, and riders remember which barns' colors are comfortable to wear.