It's the size of the (traction) patch that matters Published July 17, 2012 By Arthur Albert Air Force Safety Center KIRTLAND AIR FORCE BASE, N.M. -- On a clear, sunny morning ride to work, I witnessed a motorcycle accident that made me re-think my riding skills and the limited traction patch that keeps me upright on my motorcycle. As I left my neighborhood, my neighbor was on his motorcycle directly in front of me. We were both traveling between 7 and 10 mph. He started a right turn out of our housing area and applied throttle to take him through the corner. A small amount of sand on the road combined with the throttle was enough to cause the rear tire to lose traction and wash out, forcing the rider to straighten the motorcycle and launch head-on into a 6-inch curb. The rear tire lifted off the ground; the rider was ejected and thrown forward toward a concrete retaining wall. Luckily, he came to rest short of the wall, otherwise he would have struck his head and he wasn't wearing a helmet. The rider had no serious injuries. His bike didn't fare so well. The customized cruiser received significant damage to the forks and left side. Assuming the road was dry and clean, as my neighbor did, I've had my motorcycle wash out on a curve. I failed to recognize the potential hazard and how a small amount of dirt, dust, sand or gravel would limit my motorcycle's traction patch. The size of the traction patch will vary depending on the size of the tires, weight of the motorcycle and specific lean angles. When you add another traction-limiting source, such as over-powering in a lean, the risk of a mishap increases. So the question is: How do we properly manage and offset this potential hazard? First, as riders we need to be aware of our motorcycle's traction limitations. There are two main factors that will determine whether you'll carve that corner like a laser beam or slide out and hurt yourself: the coefficient of friction and the tire's side force. All these forces are applied to that little traction patch. How little? Sit on your motorcycle, hold it up straight and have someone outline the tire patch that makes contact with the road. Note the small size of this area. Next, lean the cycle slightly to the left or right and have your assistant outline the patch touching the ground. You'll see how limited your traction zone is and how small a tire area you are relying on to keep you upright and stable. Once you understand the bike's limited traction patch, you must also be aware of how vigilant you must be in identifying obstacles or contaminants in the road that could further limit this small traction patch's ability to keep the wheel from sliding. Sand, ice, water, gravel, etc., will dramatically decrease the coefficient of friction and make it easier to slide. You either need to increase the turn radius to decrease the side force or, like my neighbor, add a little throttle. Don't assume that just because the road where you're currently riding is obstacle free that conditions will be the same around the corner or on the other side of town. Powering out of a corner changes the velocity vector and decreases the relative side force which, in turn, decreases the amount of traction necessary and may be enough to overcome a slip. On a dry surface, it'll allow a sharper turn with more lean than would be possible without any acceleration. However, if you add too much throttle the wheel will lose grip and traction will decrease dramatically. This is a "practice before you try it for real" maneuver. Mastering or applying power will keep you at the top of your game and put you well on your way to preventing a mishap like the one my neighbor experienced. Finally, if all your preparation and understanding of your motorcycle's traction patch fail and you lose traction and wash out, wearing all the proper personal protective equipment (helmet and body armor) will improve your chances of walking away to ride another day. The rider I helped was lucky - lucky he wasn't riding fast enough to be thrown head-first into the concrete wall. Ride cool, ride smart and arrive alive. Be sure to manage your risks, adjust your speed to conditions, wear all your PPE and ensure your helmet is approved by the Department of Transportation. Remember -- the Right Skills, the Right Training and the Right Attitude.