Swimwear Fabric – what does it all mean?

Feel like you need a chemistry degree to understand the array of swimwear fabrics? Well there certainly are a lot of chemists and engineers busy developing the fastest, sleekest, most durable swimwear fabrics possible. And yes, it’s difficult to decipher the array of options from Speedo, TYR and Nike so we thought we’d offer a little lesson to help you navigate all this swimwear.

There are really two sets of criteria for buying swimwear, the first are practical considerations while the second are more about performance of the athlete in the water. For most of us, the practical considerations are really what matter, things like how long the swimwear will last in chlorine and sun, how well the suit fits the body, and whether it provides support.

High performance athletes will care more about reducing suit drag, skin friction and water absorption. They want to be like dolphins and slide through the water at incredible speeds, but not so fast that FINA bans their suits from competition, but that’s a whole different blog post…

While there is an amazing selection of swimwear fabrics, for most of us, understanding the pros and cons of spandex, nylon and polyester is probably a good place to start.

Most swim suits are made from spandex (trade name Lycra®), polyester, or nylon. Combining them gives you the very best performance and value.

Just a note: Say “no” to cotton. It’s rare to find any cotton in a good swimwear. It absorbs water, doesn’t have stretch and won’t last in the chlorine. Avoid it.

Almost all swimwear has a percentage of spandex because it is so elastic that it fits the body better than nylon or polyester. Spandex is not very comfortable on its own and breaks down quickly in chlorine. The higher the spandex percentage in a suit the faster it looks like tissue paper when wet.

Nylon is very strong, lightweight, dries fast, and is non-absorbent but it is not very durable in a chemical environment or the sun so doesn’t last long. I had a very nice baby blue nylon suit that turned into a rather shockingly see-through number right before the eyes of everyone in the pool but me.

Polyester doesn’t have the stretch of spandex but it sure lasts a lot longer because it’s more chlorine proof and fade resistant. PBT is being used by Arena and Speedo in their Endurance line. It’s a texturized polyester with natural stretch similar to spandex.

Most manufacturers like Speedo, TYR and Nike have spandex blends that increase durability but are not quite up to poly blends. Speedo combines 26% Xtra Life Lycra with nylon and claims it will last 5 to 10 times longer than ordinary spandex. Nike’s Lycra suits are 81% nylon and 19% spandex.

For most aquatic activities the best bet for a suit that will stand up to chlorine and sunlight and last a good long time is a one that’s made with a combination of polyester and PBT.

Speedo promotes their Endurance fabric, a 50% Polyester and 50% PBT blend, is their longest lasting, best selling and is 100% chlorine resistant. I have a number of their suits around the house that do seem indestructible. Adding 50% PBT provides more 4-way stretch giving more comfort and body fit than suits with a higher level of polyester. Arena offers a line of suits that are 53% poly and 47% PBT.

There are a number of 100% polyester suits including TYR’s Durafast line and Nike’s Polyester. They don’t fit very well to the body but, for most of the pure polyester suits, that’s the idea. They are actually purchased for the extra drag they provide because they make training harder and when you slip into your spandex for a race you feel really sleek and fast.

We can’t say too much about the ultimate competition fabrics, like those used in Nike’s NX, Flex of Swift EV3, Speedo’s Fastskin, TYR Tracer or Fusion or the Arena Powerskin (this one actually incorporates carbon fibre into the weave!). If we said too much we’d have to kill you. The manufacturers are very stealthy about their creations and are always upping the ante with new fabric formulations, finishes, suit construction and secrets. And besides, we don’t know anyway. You may not a chemistry degree to figure it all out but certainly a private investigator’s badge would be helpful as the manufacturers guard their formulations like state secrets. Suffice to say that they fabrics are what you want if you want to go really really fast, with the minimal drag and the latest technology. And we have them all here at AquaSportWest.