Skills and Techniques for Mountain Bikers
Jim Zarka, Bicycle Books, 1992
Chapter Seven: Clothing For Off-Road Cycling
<discussion of clothing layers omitted>
Cotton
Most people agree that cotton is one of the most comfortable fabrics around, which accounts for its wide popularity. Cotton is a durable, cellulosic fiber harvested from the cottonseed plant. The fibers are very short, 1/2 to 2 1/2 inches long, and are hydrophyllic: they absorb and retain moisture easily. On a hot summer day, when no rain has been seen for weeks and you are going for a quick 60 minute bike ride, cotton is a fine thing to wear. Let the weather change suddenly, however, and get that favorite T-shirt and pair of shorts wet, and they instantly turn into death cloth next to your skin. Through conduction, cotton will drain your body of its warmth while at the same time refusing to dry. Whatever insulating properties it had when dry, and they are negligible to begin with, are now completely defunct. It would be best not to be wearing it al all, at this point. For this reason, you should be very careful about wearing cotton in any situation where your safety and warmth might be at risk.
Wool
Wool is an amazing natural insulator. The natural crimp of its fibers traps the surrounding air, providing a microclimate of warmth surrounding your body. Wool fibers range in length from one to 18 inches, and therefore can be used to make many types of garments with differing qualities.
Quality wool clothing often still contains the natural oil, or yolk, of the fibers. Yolk consists of wool grease and suet, or dried sheep perspiration. Some wools can therefore tend towards being hydrophobic, repelling water fairly well. On the whole, however, wool does absorb water. The fibers do not compact when wet, though, so they maintain those air pockets that help retain body heat. Wool would be an excellent medium to use for your insulating layer. It is affordable, works in adverse weather conditions, and is a natural way to use less petroleum-based synthetics. Some of the disadvantages of wool are that it is both heavier and more bulky than today's high-tech insulators. Other natural fibers that insulate well are alpaca, mohair, vicuna, and cashmere.
Linen
Linen is a smooth, strong fabric made from the stem of the flax plant. It absorbs moisture and dries quickly. Its fiber ranges between six and 20 inches in length. A lot of casual outdoor wear is made from a blend of cotton and linen. As with cotton, linen is fine for a spin around town, but it does not insulate well — whether wet or dry.
Silk
This queen of fibers comes from the completed coccoon of the silkworm. It is the only natural filament fiber, its average length being 1000 to 1300 yards (or one coccoon's worth). To consturct a coccoon, two streams of liquid silk pour out of glands near the silkworm's jaw whild swinging its head from side to side in a figure-eight movemnt. The silk hardens on contact with the air.
Besides being elegantly beautiful, silk is the strongest natural fiber, stronger than a wire of the same diameter for many types of steel. It is fairly elastic, weighs very little, and is warmer than cotton, rayon, or linen. It therefore makes a good insulating unwear for moderate conditions. The disadvantage of silk is that it is not hydrophobic, retaining moisture and sweat instead of wicking it away from the skin as readily as synthetics.
Synthetics
Most active outdoor wear is now made of synthetics. To produce synthetic fibers, two or more elements are chemically combined to make a new compound. These polymers start as liquids that are pushed through tiny, fiber-width holes in spinnerets. The liquid fibers then harden, with their diameter, shape and density dependent upon the polymer composition and the spinneret used. Moisture transport, insulation, and heat dissipation can now be isolated and defined qualitatively to create use-specific fibers for almost any need. This technology has led to a variety of new synthetics, with new brand names introduced every year.
Rayon
Rayon fibers are made from natural cellulosic material — wood pulp or cotton linters — that have been chemically regenerated. Rayon was the first artificial fiber made, and is used in combination with other synthetics in many types of outdoor gear. It is a soft and versatile fiber that is hydrophobic (like most other synthetic fibers). Garments made with rayon make a good secondary insulation layer.
Nylon
Nylon is a lightweight, extremely strong and durable fiber made from chemicals found in coal, air, water, petroleum, natural gas or agricultural byproducts. Is is now produced in many different forms, although it first appeared as women's hosiery in 1937. Nylon is abrasion resistant and is an excellent source for the third, or outer layer of clothing. Coated nylon is waterproof, and uncoated nylon acts as a good windbreaker. Compared to other synthetics, nylon is not very expensive.
Acrylic
In adition to being made out of mostly the same chemicals as nylon — coal, air, petroleum — chemicals found in limestone are also used to make acrylics. Articles made of this material are a good secondary insulating layer, being soft and warm, while absorbing very little moisture.
Spandex
Spandex, or Lycra, as duPont call the same material, is a material with miniscule rubber bands in the weave that allow four-way stretch of the fabric. The world of fashion sportswear has definately been taken over by the world of spandex. Biking shorts, shirts, helmet covers, riding gloves, and underwear are all being made of this material, or combinations of spandex with other fibers. In mild conditions, spandex clothing is a good choice. It is very comfortable, and its elasticity allows for active and unhindered movement. These fibers can be stretched over 500% and still retrn to their original length, without breaking.
Polyester
Polyester is the most widely used synthetic fiber in the world. Again, it is a derivative of water and coal or petroleum. Polyester clothes are hydrophobic. It can also be blended with natural fibers to create clothes with many different qualities. The majority of outdoor wear has some percentage of polyester in it. Cotton / polyester blends can work well in moderate conditions. They still allow for breathability, are less absorvent than all-cotton, and dry quickly.
A popular brand-name made of polyester is Patagonia's Capilene, which virtually lasts forever. Capilene has been chemically designed to transport moisture. It also rids itself more easily in the wash of perspiration oils and other types of dirt, a nice feature in the long haul.
Medalist makes a polyester / nylon fabric called Dryline, used in their Skinetics underwear, which is quite similar to Capilene. With a hydrophobic inner layer and absorbant nylon to pull that water from the outside, these garments are functional and easy to keep clean.
Another type of polyester is called pile. Pile, and retropile (pile turned inside out) wears fantastically well, being extremely durable and very warm. In the 'olden days', pile used to pill up, forming little fuzz balls on the garment. Although this didn't hurt the funtion of the clothing at all, it wreaked havoc on the fashion-conscious. This has been rectified, with new types of pill-free pile on the market. Patagonia markets a pile called Synchilla. Maiden Mills puts out a pile-like fleece under the names of PolarFleece, PolarLite, and PolarPlus.
Polypropylene
Used as underwear, polypropylene wicks moisture away from the skin very efficiently. It was one of the first fabrics used in long underwear specifically for that reason. Along with being hydrophobic, it also has bery good insulating qualities, and is very light. Over time, polypropylene loses its wicking abilities, and tends to retain perspiration odor to the nth degree because it is so hydrophobic — regardless of washing. Fabrics that are hydrophobic hate water, so they don't get along with the water in your washing machine either.
<discussion of clothing combinations omitted>
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