|
Carla likes the feel of her cruiser. The low seat allows her to reach the ground with both feet. She has added a big windshield on the front, and highway pegs so she can stretch her feet forward. She doesn't like the appearance of hard bags, so her gear is stacked up on the back of the saddle. For the first hour, there are a few disconcerting wind gusts, but the sky is blue, the cruiser is thrumming along sweetly, and she continues to enjoy the freedom of the road. Carla takes a break at Mitchell to see the famous Corn Palace, and when she comes out to saddle up again, she realizes the blue sky is rapidly disappearing behind a wedge of swirling black clouds. Back on the superslab, the wind has shifted around to the southwest, and the gusts are getting stronger and more frequent, slamming into the bike from the left front. Carla can barely hang on. The leather fringe on her jacket whips against her exposed neck. The wind keeps tugging at her half helmet, and grit blows into her eyes behind her sunglasses. Crossing the bridge at Chamberlain, a malevolent gust suddenly hammers into the bike, slowing it and pushing it towards the railing. Carla's heart jumps into her throat as she struggles to steer the bike away from the railing. Then, as the gust suddenly passes, the bike swerves left, and she is barely able to keep it out of the oncoming lane. For the next hundred miles, she can't shake the images of a bike and rider cartwheeling off the bridge into the Missouri River, or slamming head-on into an 18-wheeler. The ride has ceased to be fun, but Carla forges ahead into the
prairie winds, refusing to delay her schedule. By the time she has battled her
way to Wall, she is exhausted, flayed, windburned, dehydrated, scared, and
angry. To top off her frustration, the engine sputtered onto reserve 20 miles
back. And when she dismounts at the gas station, a gust slams into the bike and
pushes it over before she can catch it. Most of us can empathize with Carla. Motorcycles can be tricky to control in crosswinds, especially gusting crosswinds. We try to keep the motorcycle balanced, but the gusts suddenly slam it sideways, and then just as suddenly let up. It's a constant battle to stay between the lines. Is there some method to riding in this windy madness, or do we just have to tough it out? Sometimes riders contribute to the problem, without realizing it. The fringe on Cruiser Carla's riding jacket is stylish, but it flails around in the wind, adding to the annoyance. Her half-helmet and sunglasses are cool looking, but can't keep the wind and grit out of her eyes. The forward-mounted highway pegs make steering more cumbersome, and strain her back and shoulder muscles. Stacking her gear up on the back of the saddle is handy, but that also creates a "sail" high above the rear wheel. Let's consider how different motorcycles react to wind, and how the motorcycle/rider ergonomics relate to ease of control. Sails
We should expect that wind pressure on a frame-mounted windshield or fairing would push the bike downwind. What's not so obvious is that sails mounted on the front fork will apply a steering force to the front wheel. Steering forces the bike to lean, whether it is our hands pushing on the grips, or the wind pushing on the front fender. The relative position and shape of "sails" attached to the front fork, including fenders, fairings and windshields, will have an effect on how the bike handles in windy conditions. For example, a large handlebar-mounted windshield leaning back behind the steering axis might be more stable in calm air, but will steer the machine into more of a downwind lean in a side gust. A front fender with more "sail" ahead of the steering axis might actually steer the machine upwind during a gust. Steering will be more neutral if a handlebar-mounted windshield is mounted in line with the steering axis.
A bare bike can theoretically be as stable as a faired machine, except that the wind tugging at the rider's arms will impart some unintentional steering input. For instance, a strong gust from your right will push your elbows towards the left, countersteering the bike into even more of a left lean. Saddlebags mounted no higher than the machine's Center of Gravity will be less likely to push the bike downwind. Bulky "sails" such as a sleeping bag strapped up high or a duffle cantilevered over the tail light can cause strange steering.
Ergonomics
What's not so obvious is that when you push on the handlebar grips, you use your legs to brace yourself. Cruiser-styled machines with forward-mounted footpegs and high handlebars may look "cool", but the ergonomics are far from ideal for steering a motorcycle. Sports bikes provide more accurate steering control, but the lean-forward position can quickly strain shoulder and neck muscles. So, ergonomics are always a compromise between control and comfort. Consider that the ergonomics determine which muscles are used to lean the bike. Quick, powerful steering inputs requires quick, powerful muscles, like those in your arms. To understand this concept, lean your torso forward in your chair, with your feet flat on the floor. Stretch both arms straight forward as if you were reaching for some imaginary forward-mounted handlebars. Reach out far enough that your elbows are locked straight. Now, turn your imaginary handlebars a little to the left, and then a little towards the right, and think about which muscles are doing the work. With your arms locked straight, you must use your back muscles, right? And when you're pushing with your shoulder muscles, you're probably bracing with your legs, too. Now, pull your imaginary handlebars back towards you just enough that your elbows are bent slightly, and try steering left-right again. With your arms bent, you can steer with your arm muscles, which happen to be quicker and more accurate than the larger muscles in your shoulders, back, buttocks, or legs. Rider Skill
When riding through strong winds, you must lean the bike into the wind, and that may require forceful pushing on the grip. For example, with a strong but steady crosswind from your left, pushing on the left grip will lean the bike left (upwind). If the bike drifts too far downwind, you need to lean it even more towards the wind. Pushing a little harder on the "upwind" grip will lean it over more and point back towards your desired line. Of course, when the wind suddenly decreases, or changes direction, you will need to quickly countersteer to whatever angle is needed to keep the bike within the lane. When riding through crosswinds, you may get some strange feedback from the front wheel. It may require more pressure on the grip than during a curve, since the contact patches are way over on one side of the tires even though the machine is traveling straight ahead. Just concentrate on countersteering to make the motorcycle go in whatever direction you wish, and let the tires swerve around under you. Many of us have ridden for miles through strong crosswinds, with the bike leaning over at a startling angle, controlled by firm pressure on the upwind grip. Gusting Cross Winds
Be aware of the tendency to counteract one hand with the other. When you're pushing hard on the left grip, you may be stiff-arming the right grip without realizing it, and wondering why you can't get the bike leaned quickly. So, when countersteering, try to focus your energy on one grip, and relax your other arm. In other words, to lean the bike toward the right, push with your right hand, and relax your left arm. Since we can't see the air, it helps to have some understanding of what wind does around other vehicles and structures. Oncoming trucks can push a powerful "bow wave" towards you, or the wind may swirl around behind the trailer. Be especially wary of large vehicles approaching from upwind, and move as far away as possible to avoid the blasts. When you're about to exit a tunnel or cut between two hills, be prepared to countersteer into a sudden gust. We might also note that Cruiser Carla's wind troubles grew worse towards afternoon. That's because wind typically gets stronger and more turbulent as the earth warms up. There are many locations in North America where a strong wind is expected every summer afternoon. For example, in the Columbia River Gorge between Oregon and Washington, the cool coastal air rushes inland to replace the hot air rising over the deserts. For the wind surfers, it's Heaven. For motorcyclists, it's less fun. In such locations, wise riders make the trip earlier in the morning, before the afternoon wind kicks up. Body Armor
Know When To Fold 'em
I made a quick downwind U-turn, sped back to a road maintenance area I had just passed, laid the bike on it's side in the lee of a gravel pile, and hunkered down until the squall moved on. In the "tornado alley" between Texas and the great lakes, motorcyclists must be aware of the extreme hazard of tornadoes. If there is a tornado alert, consider delaying your trip, or changing your route to ride around the area. If you do head out and find yourself in the path of a tornado, take evasive action immediately. If you have no other place to hide from an approaching funnel, tuck yourself under a highway overpass or into a drainage culvert. Don't waste any time trying to protect your bike. Homework
David Hough is a long-time motorcyclist and journalist. His work has appeared in numerous motorcycle publications, but he is best known for the monthly skills series “Proficient Motorcycling” in Motorcycle Consumer News, which has been honored by special awards from the Motorcycle Safety Foundation. Selected columns were edited into a book “Proficient Motorcycling” published by Bowtie Press. He is also the author of “Driving A Sidecar Outfit”. A pocket handbook, “Street Strategies” iis also on the market now. |
Send comments on the Metro Chapter HOG site to Brian, Al & Brad @ Webmail@metrohog.com Site Last Updated:January 22, 2004 RETURN TO HOME |