Turning a Motorcycle

Turning a Motorcycle

            Riding a motorcycle has always meant a statement of freedom or rebellion. Knowing how to ride a bicycle will remain as one of the first steps of becoming free, for all children. Learning the basics of balance and needing to pedal at the same time, could have easily taken days to learn. Turning got a bit tricky because it was never the same every time, the were always little tremors of fear as you turned the handle bars for the first time only trying to avoid a tree or Fido as he chases your front tire. The bike continuously shook when the child first started out but they got some speed and confidence the bike smoothed right out. The confidence with turning came shortly there after, because Fido constantly tried to get that front wheel and they couldn’t run him over.

            Now as a grown up, that same person wants to feel that freedom again. The wind in their face, the road rushing by only inches from their feet, the feel of leaning into a turn, the closest feeling they get to flying without confronting a fear of heights. The problem now will take them back to learning to ride all over again. They’ll learn the basics of the clutch, twist throttle, front brake, rear brake, and may think they have the balance down. Now they get on the bike and start off to learn. Going straight down a deserted street dragging their feet in fear of falling over, shaking the whole time, and they decide to turn. Since they remember how to ride a bicycle they turn the same way and because that person is only traveling at about 6 miles per hour they turn the direction they intended. Doing this a few times around their block helps them build confidence and knowledge of riding. Having rode their block for the past 2 days they decide to go out exploring. They head out on the open road or at least as open as confidence and fear will allow to practice what they have learned. Riding down an open road with traffic at about 20 miles per hour they decide to changes lanes, so turning the handlebars just the way they did around the block and, surprise, they go the wrong direction! They quickly realize that all this time they had thought that turning a motorcycle was the same as turning a bicycle, although it’s completely different and involves many more inputs, knowledge and experience.

            It turns out that even though a motorcycle and bicycle look similar, they are actually completely different when it comes to turning. Turning a motorcycle can actually be explained with science, and Professor Joel Fajans discusses this science in his article in the American Journal of Physics titled “Steering in bicycles and motorcycles.” Joel Fajans is a Professor of Plasma Physics and Nonlinear Dynamics at the University of California at Berkeley. He is an avid bicyclist and wanted to try to explain how bicycles and motorcycles actually turn. Fajans explains the physics that impact the turn and the process of turning. He describes the mathematical calculations used to determine out the forces that act on the bike and the rider.

            Similarly counter-steering is turning the handlebars counter to the desired turn, which creates gyroscopic precession that leans the bike the opposite direction. The process of push left, go left and push right, go right is applied to motorcycles above 5 miles an hour to make them turn the correct direction. The mathematical equations Professor Fajans demonstrates to show gyroscopic torque and counter steer are extremely complicated. The weight shift method of assisting in turning a motorcycle can also be explained with the same mathematical equations. The hip bend is used to assist in turning sharper angles while maintaining maximum torque and speed. 

            The other methods that the professor gives examples of to initiate a turn are: uneven road surface, push harder in one pedal than the other, lean the bike over by the handlebars, accelerate with the wheel turned, or employ the growing oscillations.  These are all things that the rider can take advantage of to initiate a turn, but still need counter-steer to continue the turning process.

            The photo shown here (taken by Photographer Martin Heath at the Catlunya Grand Prix Circuit on June 14^th 2009) shows Valentino Rossi on the Team Fiat Yamaha rounding a lightning fast left handed turn. The track at this point angles slightly up and away from the turn so that the rider can achieve greater speeds during the turn. The crisp red and white lines are actually uneven rows of concrete called the rumble strip that are angled up slightly away from the track and used to outline the edge of the racetrack for quick identification and assistance in cornering. These two angled surfaces give the appearance that the rider is actually horizontal to the ground, when in actuality he is leaned over at about a twenty-five degree angle. The bright colors make the rider and bike look exciting like the bright neon lights of the state fair at night. The blurred asphalt and front tire give the picture speed and warmth. Having the grass in the corner of the picture just inches away from the riders’ head makes you aware of the danger inherent in doing this maneuver. The reason the rider can sustain a turn of this angle is physics. First the counter steer caused him to enter the turn to the desired angle that he thought was needed to complete the turn. Second his body position helped the bike keep a low center of gravity. Lastly the uneven angle of the pavement caused him to continue the turn through at such an extreme angle.

Now imagine that same rider scared, shaking with their confidence shot to hell after being scared half to death while changing lanes. That same learning rider decided to get off the main road and head back home on the back roads with less traffic. On the way home the rider decides to simply practice weaving back and forth in his own lane getting more comfortable with counter steer. Once they are comfortable with counter steer and the way the bike moves under them, then they can actually just ride and enjoy the feeling. Getting to the point of comfort on the bike will take a while but as long as they take it slow they’ll do fine and get to experience that age-old feeling of freedom. Rushing out on the first day of learning to ride a bike and being over confident cause a lot of problems. Knowing a persons limits and taking the learning process slow can really affect how they end up viewing motorcycles and the experience that accompanies them. So take it slow, ride at a comfortable pace and keep the bike rubber side down. 

Work Cited

Fajans, Joel. “Steering in bicycles and Motorcycles.” American Journal of Physics 68.7 July (2000): 654-59.

Heath, Martin. Elbow Down. 2009. Martin Heath Photography, London. Web. 19 Oct. 2011. http://www.martinheathphoto.com/gallery.php?s=392.