Yamaha Motor's Waza and Sube

Dispelling Motorcycle Myths

Vol. 1 “They say you shift your body weight to make a motorcycle turn...”

Mayu

I started riding motorcycles 17 years ago and what I liked about them was definitely the fun of cornering. But I only feel like I really rode well through a corner every now and then. I honestly don’t really understand the basics, like why a motorcycle turns or what the secret is to skillful cornering.


Cornering is what makes motorcycles so fun to ride.
Prof. Max

Hmm, well Mayu, how do you make the bike turn? Do you have your own way of going through a corner? And why do you suppose a motorcycle leans when it turns?

Mayu

Well, I look ahead towards the exit of the corner and put my weight on the inside footpeg (#1).


(#1) Putting pressure on the footpegs is sometimes a way to aid in starting a turn.
Prof. Max

Right. When going through the slalom course at a riding school, they teach you to put your weight on the footpegs to help get the bike to turn. But Mayu, when you’re riding on the road do you do this every single time you turn? It’s not like I never put my weight on the footpegs when cornering, but when I’m out touring I almost never do. After all, the footpegs are where you rest your feet when you’re on the bike, right?

Mayu

Really? So I guess it’s more important when you really want to lean the bike way over. And shifting your body weight into the turn too is key, I think. MotoGP riders move their body weight so far over to the inside of a corner that their knees and sometimes their elbows scrape the track. So to make the bike lean you have to move your weight, right?

Prof. Max

Yes, racers in MotoGP and other top series typically use a dramatic hang-off style on their bikes (#2). But hanging off isn’t a “requirement” for making a bike lean in order to corner. I see it simply as one way they use their bodies to balance out the centrifugal force at work. After all, motocross riders often lean outward when cornering and that puts their body weight in the opposite direction of the turn (#3). In other words, where the rider’s weight is shifted isn’t the same direction as where the bike is being leaned.


(#2) The “hang off” style of riding prevalent in MotoGP

(#3) Motocross riders lean their body weight in the opposite direction of the turn.
Mayu

So both MotoGP riders and motocross riders move their body weight to maintain balance when cornering. Does that mean there’s a relationship between moving your body weight and leaning the bike while turning?

Prof. Max

I have an idea. Watch this video. It shows one of Yamaha’s R&D projects where a robot rides a motorcycle around a racetrack. As you can see, the robot doesn’t move its weight around at all. It can’t! Nevertheless, it still rides the bike through corners smoothly and at high speed.

Mayu

Yes, but they’re using electronics to control the bike and the robot, right? It also feels a little weird to see a robot riding a motorcycle designed for humans.
Anyway, how is MOTOBOT making the bike lean into the corners without moving its body weight? Is he moving the handlebars? Is he pushing the bars in the opposite direction for a split-second?

Prof. Max

“Pushing the bars in the opposite direction for a split-second” is one way to put it. That’s called “countersteering.” (#4) For example, when you want to go left, you push the left handlebar to turn the handlebars to the right for just an instant, but then the bike leans to the left: the opposite direction. I think everyone has experienced this and in fact, that’s the key.

When a rider corners on a bike, they’re using countersteering, whether they’re aware of it or not. Even though the steering angle is extremely small, the rider is actually pushing the handlebar in the opposite direction of the turn.


(#4) Countersteering: Pushing lightly on the left handlebar moves the handlebars to the right for an instant and causes the bike to lean in the opposite direction.
Mayu

Oh, so you push the handlebar in the direction you want to go and bike leans and turns that way.

Prof. Max

That’s right. If you want to turn left you slightly push on the left handlebar to move the handlebars to the right and then the bike leans left. That’s countersteering.

Here’s another example: imagine you’re balancing an umbrella in the palm of your hand. If you want to move it left, you have to momentarily move your palm to the right so the umbrella will start to fall to the left. Then you move your hand to the left to keep the umbrella balanced (#5). Cornering on a motorcycle is very similar.

Basically, a rider uses countersteering to cause the bike to lean over in the direction of the corner. Once a certain lean angle is reached, the rider unconsciously stops countersteering and by releasing the strength in his or her arms, the bike will naturally keep the handlebars turned in the direction of the corner.

When this happens, the bike is leaned over, but is balanced and corners smoothly and naturally. Most riders perform these actions automatically and without conscious effort. And since the handlebar angles involved with countersteering are incredibly small, from less than 1° to 2° or so, most riders don’t feel anything at the handlebars when they’re doing it.


(#5) The motions made when countersteering are similar to those made when balancing an umbrella in the palm of your hand.
Mayu

I see, so that’s how countersteering works.

Prof. Max

MotoGP riders turn their handlebars in various different ways when cornering; sometimes they turn the bars a lot, sometimes very little. Some of these are likely techniques only used by the best riders in the world. You might find it interesting to watch some of the bikes’ onboard footage from a MotoGP race and observe how the riders manipulate the handlebars when cornering.

Mayu

I see, thanks for explaining everything! So riders really do have to use the handlebars to make the bike lean and turn. But now I wonder, how can people do such a complex thing without even thinking about it?

Prof. Max

Human beings evolved over thousands of years in the Earth’s gravity, so the ability to skillfully balance gravitational forces probably comes to us naturally.

Prof. Max

“You shift your weight to make motorcycles turn” is probably just another motorcycling myth.

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