What to wear on a bike

When I’m riding around and looking at other motorcyclists, the most common outfit I see is jeans and a jacket. I used to dress like that too, until I dropped my bike, ripped my jeans and tore open my knees, pretty much ensuring I will never wear a miniskirt again.

Legs are the most frequently injured body part in motorcycle crashes, followed by arms, then the head, according to the 2004 Motorcycle Accident In-Depth Study, or MAIDS report.

Yet the legs are the least protected body part, followed by the feet and hands.

Because 90% of motorcycle crashes result in injury, it’s a wonder more riders don’t cover up, but there are reasons. Often, it’s blissful ignorance or an under-assessment of the risks, but it’s also the weather where you ride, the culture of your bike and the expense of gearing up, which can cost upward of $2,000 if you buy the best stuff.

Personally, I chalk at least some of it up to confusion. It’s just hard to know what to buy. Unlike Europe, which standardized protective gear in the late ‘80s, the U.S. doesn’t have a system to ensure that protective items will perform to a certain standard in a crash. And, like most safety issues having to do with motorcycles, much of the publicly available research on materials is old.

In the early ‘80s, a materials scientist at Cambridge University analyzed 100 sets of crashed-in-the-street motorcycle leathers, looking at where they were scarred to learn about the highest points of impact. Elbows and knees ranked highest, followed by shoulders and hips, which is why jackets and pants are often equipped with armor in those areas.

That armor is more effective when it’s hard plastic, rather than soft, foam pads, and built in to protective apparel so it won’t move on impact. But that raises two questions: What are the most protective materials for motorcycle garments, and how should those garments fit?

Because most injuries are caused from skidding along the ground, abrasion resistance is vital. One of the best sources on abrasion is the famed “Torn in the U.S.A.” drag test conducted almost 20 years ago by now-defunct Cycle magazine. For that test, clothing samples were stitched to a 75-pound sandbag and thrown out of the back of a pickup truck to see how long they’d take to disintegrate. Competition-weight leather (1.5-1.7 mm thick) lasted longest -- about four times longer than Kevlar, five times longer than 440 denier Cordura nylon and 20 times longer than denim jeans, which take about half a second to give out in a 30 mph crash.

Regardless of a material’s abrasion resistance, how well a garment holds up on impact depends on an array of variables that are rarely cited on a garment tag.

In the case of leather, there are wildly different grades and thicknesses -- from beefy competition weights to thinner, buttery soft “fashion” leathers that offer less than 5% the protection of their weightier counterparts. That issue is complicated by the caliber of the hide from which the leather is cut. A natural hide is more consistent in its thickness than a hide that has been corrected.

In the case of textiles, it isn’t just the caliber of the material but its construction. Kevlar ranks second overall for its abrasion resistance, but it’s more protective when it’s knitted, rather than woven. Cordura nylon ranks third, but it needs to be at least 440 denier and should also be coated.

Of course, all the abrasion resistance in the world means little if the seams or zippers on a garment burst or tear on impact, or if the garment fits too loosely or isn’t worn at all.

Motorcycle apparel should always feel comfortable but snug. It should also be something the rider likes the look of; otherwise, he isn’t going to put it on.

As Marc Bay, head designer for Canadian motorcycle apparel manufacturer Joe Rocket, astutely observes: “The most protective motorcycle jacket is the one a person will wear.”

susan.carpenter@latimes.com