This wonderful article was written by Bill West who has graciously allowed me to post it here. It contains an interesting and knowlegeable point of view regarding various fibers for riding suits or outfits. It was originally a post to the VFR List regarding the alternatives to leather. It was very interesting to me and I expect to others.
I wrote the following discussion in response to a thread active a few weeks ago, but by that time the thread was getting a bit stale so I sat on it instead of burning lots of bandwidth. But now the time is ripe!
A General Discussion of Materials Available for Protective Riding Suits.
Fifteen or so years ago I finally decided that I could afford to invest in some kind of protective riding suit for motorcycling, after some 15 or so years of riding without one. There is no need to discuss the wisdom of this delayed realization, I'm just proud that I finally got smart enough to make it at all. At that time leathers were really the only choice with any kind of plausible proven record. This was no small investment, so I sent to many vendors for brochures, including a company then known as Thurlow Leather World. They're still around and still worth searching out if you're in the market for leathers.
One of the things that first impressed me about Thurlow was their informative brochure, which immediately set them apart from their competition. Not only did it describe their products and bring to your attention how they would make your motorcycle go much faster and increase the frequency and satisfaction of your sexual contacts, it went on to discuss the protective properties of various materials. Even if I had not ended up choosing their product, whatever choice I had made would have been based on much better information thanks to this brochure. I would like to briefly review some of the points covered in the Thurlow brochure, and will say up front that I accept full responsibility for any errors, misquotes, misinterpretations, or childish over simplifications. They pointed out that leather, unlike any man-made product, has its fibers oriented more-or-less randomly which means that leather's resistance to tearing is not conditioned on which direction the tearing force is coming from. Any woven fabric's tear resistance is stronger in some directions (parallel to the fibers) and weaker in others (normal to the fibers), which affects puncture resistance as well as resistance to straight tears or "chafing through." Also, leather is less likely to ignite when exposed to frictional heat or other ignition sources (burning spilt gas, anyone?), and no matter how hot it gets it will not melt and stick to you. There are very good reasons why motorcycle race drivers wear only leather in spite of recent significant advances in synthetic fiber and cloth technology. The Thurlow brochure went on to discuss the properties of different types of leather, pointing out that not all leather is created equal and concluding that the type they use is best (surprise!). I found their arguments persuasive, and my subsequent personal experiences (including one off-vehicle excursion which featured an extended cruise along freshly-graveled rough asphalt, followed by a rapid traversal of a drainage ditch, and ending in a blackberry thicket) offer no contradictory evidence. They did a nice job on the repairs, on time and for a reasonable price.
In the 15 years since I bought my leathers, as far as I know there have been no relevant breakthroughs in man-made fiber technology that would invalidate Thurlow's conclusions, so why did I recently buy an Aerostich riding suit, which is made entirely of synthetic materials? The reasons have mostly to do with comfort under my day-to-day riding circumstances, which feature a short daily commute, various made-up excuses for running "errands" around town, and the occasional weekend jaunt in search of twisty bits. Further, in the light of 15 more years of riding experience I concluded that with my riding style and conditions I most needed impact and chafe protection and was subject to less risk from fire or friction-induced heat. While safety was still the primary consideration, I had a better feel for what were my real risk factors and I was willing to make what I felt were some acceptable minor compromises in favor of comfort. The well-protected rider must fight an unending war with moisture in the Seattle climate, although maybe not in the sense that you might expect. Sure, it does sometimes rain here, but usually the rain is not very heavy and for short hops the leathers were sufficiently water-repellent to keep them and myself dry as long as I occasionally gave them a good dressing of mink oil. (However, I hesitate to describe the impact of this activity on my cat's behavior in a posting that children or fundamentalists might access).
For longer rides or heavier rainfalls it was necessary to pull a thin waterproof rainsuit over my leathers, which was pretty effective at keeping the rain where it belonged. The more difficult battle is with temperature and my own moisture. The climate here is pretty mild, and for much of the year I found that it was difficult to stay cool enough under my leathers, especially if I was wearing my office clothes underneath, and if I had to put on my rain suit then all hope was lost. Accordingly I started looking at alternatives. Heavily vented and perforated leathers are available, but they didn't seem to me to offer the sort of all-weather versatility that I was looking for. I wanted to have a single suit that I could wear any day of the year and that would offer reasonably good crash protection, could be easily adjusted for heat and ventilation control, and would keep heavy rain out while letting the perspiration out too. Synthetic fabrics seemed like the best compromise. I didn't consider natural fibers such as the heavy waxed cotton used in some traditional riding suits since these materials do not offer comparable crash protection even though they score well in terms of comfort and utility. Don't get me wrong, such suits offer substantially more protection than shorts and a tee-shirt, but they're still not in the same league as leathers or synthetics in terms of meaningful damage control. (Before anyone flames me for that assertion, I ask only that you consult any table listing the strengths of common natural and synthetic fibers, available at your local library's reference desk. Also, please spare me the amusing and instructive anecdote about your Uncle Llewellyn's remarkable experience at the Isle of Man when he was riding his 1904 Puckerwhistle "Flying Mastiff" in what he thought was the Vintage event when he T-boned a Ducati 916 at full chat, and was fished, shaken and distraught but otherwise unharmed, out of the quarry still wearing his World War I surplus trench coat, puttees, and aviator's leather helmet while the fully race-armored Ducati pilot had to be extracted piecemeal from the all-too-mortal remains of several nearby cattle.) But which synthetic fibers?
For several years I was the lead gear designer for a company that makes heavy nets for commercial fishing and in the course of that I gained some knowledge of the properties of modern textiles and their performance under harsh conditions. To make a long story short we constantly monitored the literature on numerous synthetic fibers, performed technical analyses on the more likely-looking new candidates in comparison with existing materials, introduced the surviving prospects to the fishing industry in real-world prototype demonstrations, and monitored the fishermen's experiences with all materials, old standbys as well as the latest and greatest. Kevlar was one of the fibers that looked very good indeed until we got to that last stage, real-world usage. Kevlar is immensely strong in direct tension, comparable to steel on a diameter-for-diameter basis, yet is as light and flexible as nylon. (Oh mighty and all-knowing technoids, please forebear and forgive me and spare me from a flame war regarding testing procedures, appropriate units, and/or the characteristics of unusual but extremely nifty alloys. This statement is for informing the ignorant masses, not for _Proving Anything_ to you, as if that could be done by such as I, and is true as stated). Although fire resistance is seldom an issue in commercial fishing nets, for all practical purposes Kevlar is fireproof and is a reasonably good insulator. However, its abrasion resistance is rather poor, so poor in fact that when we built fishing nets out of Kevlar ropes and twines, within very short order the nets simply fell apart. The Kevlar netting had been literally chewed to bits from the inside out from internal abrasion as the lines flexed and the individual fibers sawed back-and-forth against each other.
Kevlar is great stuff indeed if you can build your product with it then permanently immobilize it under tension or within the matrix of a composite material, never allowing it to flex or move again. It performs very well as standing rigging on a boat or as the fabric in composites (e.g. lightweight bulletproof helmets, kayaks, or canoe paddle shafts), but I would not trust it for very long in any application where it must repeatedly flex, as in a riding suit made from woven Kevlar fabric. Kevlar is probably OK in bulletproof vests or other applications where it can be woven into "batts" or pads that can then be immobilized within the structure of the garment so all normal flexing will take place around and between the batts without forcing them to flex also. The driving suits used by race car drivers feature Nomex fabric, a very close relative to Kevlar, but this is due primarily to its flame resistance and not so much its ability to offer impact, chafing, or puncture protection. Still, I wonder how many times they use each Nomex suit before retiring it.
We had considerably better results with another high-technology fiber known as Spectra, which is nearly as strong as Kevlar but has outstanding abrasion resistance. It has been a tremendous success in commercial fishing gear among other uses. However, I would not choose it as a material for a riding suit because it loses its superstrong properties at a rather low temperature, a temperature that could easily and quickly be reached as a downed rider goes sliding down the road. It also has a relatively low melting point and temperature of ignition. So what's left? Among the widely-available, reasonably-priced fibers, nylon has the greatest strength and has reasonably good abrasion resistance. Its properties are well understood and product forms have been developed that optimize chosen aspects of its performance. A well-designed riding suit made of carefully-chosen nylon fabrics can offer abrasion and puncture protection approaching that of leather. Good design and well-chosen suit features and components such as pads, vents, high-visibility panels, and waterproof but breathable liners can add to its protective, comfort, and weather-proofing characteristics.
After looking at various alternatives, some of them quite attractive and considering features, user feedback, company product information, and price, I chose an Aerostich Roadcrafter two-piece suit. After a year of use I do not regret that choice, although I have not yet tested its crash protection performance and have no plans to do so. What's the take-home message for those of you who may be planning to buy a riding suit? I still wear my Thurlow leathers whenever weather and other circumstances permit because I like the way they feel and look. However weather and circumstances don't often permit so then I am quite comfortable, confident, and happy wearing my Aerostich. My needs and wishes are probably not the same as yours, so you will want to consider other choices. However, I encourage you to examine your needs and study the various offerings so you make the right choice. "All the racers wear one" is a good argument only so far as your needs and riding circumstances are exactly the same as a racer's. "It's made from bulletproof material" is meaningful only if you expect to be shot at, which might be a consideration for riders in some areas. Finally, the safest or most expensive riding suit available will not do you much good if you don't wear it because it's uncomfortable or you think it makes you look like a fool.
Ride safe - Ride smart - But Ride!
Copyright © 1997 Bill West.