While I don’t find Prof. Klein’s papers available online, but the summary Karen Lingel gives make intuitive sense.
Taking this one step further, when I learned to ride a motorcycle, I was taught to initiate a turn by “countersteering.” This consists of slightly turning the handlebars in the opposite of the direction one desires the motorcycle to turn. I’ve seen a variety of explanations of why of why this works (including gyroscopic effect :)), but would like the Straight Dope. I’ve also noticed that it produces much quicker steering on my bicycle than just leaning.
Motorcycle instructor, etc., Keith Code describes an experiment he performed (link) in which he modified a motorcycle to have a second, fixed set of handlebars above the original handlebars (so that one could not give any steering input through the bars) and claims that it is impossible to turn tightly or smoothly.
Welcome to the Straight Dope Message Boards, Salex, we’re glad to have you with us!
When starting a new thread, it is helpful to other readers if you provide a link to the Staff Report upon which you are commenting… helps keep us all on the same page, so to speak.
Welcome, Salex. I fixed your link, and it only took two tries. I can’t say that I’ve seen a URL with a dollar sign before, and I guess the software doesn’t much like them. I got it to work, though.
A motorcycle (nor a bicycle for that matter) can’t actually turn without leaning. This has a lot to do with the shape of the tires and a lot to do with steering trail. So, when you countersteer, you actually force the bike in the “wrong” direction momentarily, essentially making it start to “fall over” in the direction of the turn. Once that action has started, you simply balance through the turn with additional handlebar input and throttle.
All I know is that once I got myself into the habit of consciously countersteering, control of my motorcycle was WAY better, smoother and more predictable.
I recently posted the following on a related thread. I think it clarifies some of the issues. Shape of the tires is not really a factor (they have to be able to provide traction) and trail just makes it all a bit easier. Some clarification of what trail is may be available at www.paintbros.com .
A bicycle in motion is balanced primarily by the rider’s input to the handlebars. If the rider presses forward on the right bar (counter-clockwise torque), the front wheel is steered to the left forcing the bottom of the tires to the left. There is nothing to force the rest of the bike and rider to the left so inertia causes them to go straight. With the majority of the bike and rider going straight and the contact patches of the tires going left the bike has no choice but to lean to the right. To restore balance, the tires must be brought back to their position under the bike. This is accomplished with rearward pressure on the right bar (clockwise torque). This is an on-going, dynamic process.
When a bike with positive trail is leaned to the right, gravity applies clockwise torque, which, if the bike is moving, tends to restore balance. The greater the trail, the greater the clockwise torque - increased stability. Because of this effect of trail it is possible to ride no-handed by shifting one’s body weight.
In executing a turn on a bike, a rider initiates the turn by applying torque to the steering (handlebars) in a direction opposite the direction of the turn. This causes the bike to lean in the direction of the turn. Throughout the turn torque is constantly applied to the steering by a combination of trail’s effect and rider input. Finishing the turn entails applying torque to the steering in the direction of the turn to bring the tires back under the bike.
During the turning the vector sum of gravity and inertia (centrifugal force) must pass through the contact patches of the tires or the bike will spin out or high-side depending on the direction of error.
I think countersteering is a misnomer. When you turn, sure you push the opposite handlebar than might seem intuitive to a non-rider, but you push the bar down to get the bike to lean the way you want, not forward changing the direction of the fork. This is a no-so-subtle, but important, difference.
I don’ think it’s a misnomer because it is always discussed in a context of comparison with steering a car or a trike and it is definitely counter to that. It is also true that you initiate a RIGHT turn by pointing the front slightly to the LEFT.
Since the front forks can only rotate about the axis established by the bearings in the neck, any push, whether it is up, down, forward or sideways is translated into clockwise or counterclockwise torque.
If you ride a motorcycle with drag bars and your hands straight out in front of you it is more obvious what is going on. Click here http://www.paintbros.com/DutchmanRides-02.gif to see a bike with drag bars being ridden.
To clarify this for yourself, try changing lanes one-handed. Do it at moderate speed (say, around 30 mph) and with no traffic. Do it carefully several times, paying particular attention to the pressures you exert with that hand.
First of all, I ride a standard bike meant for humans (as in your picture, nice bike btw), not a rice rocket, so my hands are straight out in front of me, the way they’re supposed to be
And when I turn, the fork isn’t rotating. In fact, in your picture it looks as if the fork is turned in the direction of the turn… anti-counter-steering.
To clarify this for yourself, try changing lanes no-handed. Do it at moderate speed (say, around 30 mph) and with no traffic. Do it carefully several times, guiding the bike with the pressure of your outside knee against the gas tank. Then try again, with your hands, consciously pushing down and helping with your knees.
I think if you concentrate on shifting the weight of the bike rather than pointing the fork in the wrong direction (or any at all) your turns will be more efficient.
I think counter-steering is just a shorthand description of this behavoir.
Tell you what. You try my experiment and I’ll try yours… unless you’re adverse to learning something.
OK, maybe I misunderstood the tone of your answer. Actually I have changed lanes no-handed both on bicycles and motorcycles. It drives my brother nuts. The bike can be steered by weight shift only but it takes LOTS of effort. If you afix a bar like a handlebar to the frame instead of the fork, (I’ve only tried this on a bicycle) it is easier to apply weight shift but still nowhere near as effective as applying pressure to the handlebars.
For several years I was a certified bicycling instructor. For decades before that, I was a bicyclist and motorcyclist. I’ve held an amazing range of beliefs about steering. When I was in US NAVY Guided Missile school I learned all about gyros and thought that was the answer. Then when that quy built the self-cancelling gyro wheels, I had to unlearn what I thought was true and start over.
I already knew you push left to go right, but I thought that induced gyroscopic precession. Wrong! (In 1960 I had an eleven-year-old Harley 74 and it was popular in New London, Conn. to put little short, clip-on type bars on the lower triple-clamp and steer with your feet while leaning back on something like my seabag. You definitely learn the “counter” part doing that. Remember, those old Hogs didn’t have a throttle return spring.)
In the picture you said it looked like I was turning the wheel to the left in the left turn. At that point, I was beginning to steer out of the turn. Actually, throughout any turn there is a constant, minute series of right/left corrections. When I get lucky and hit a long sweeper just right and don’t have to make hardly any inputs, I just love it.
You try my suggestions and I’ll try yours to make sure I don’t remember it wrong and after the weekend let’s compare notes.
I’m not intervening as forum moderator, because the tone (although somewhat pointed) has been reasonably civil. Let’s keep it there, please: ad hominem insults are not appropriate in this forum… and we appreciate that you’re both staying in the realm of good manners.
I also want to point out that this topic is being discussed in another thread, mainly Balancing on bikes … I’m keeping this thread open because it’s arguably different, so we’ve got basically the same topic being discussed twice. Things are rarely perfect.
Hi folks,
this is actually my 2nd post. The first time this was addressed i got so frustrated at Lingle’s response, i had to get in here and post. I see i was ignored the first time, so i thought i’d write again. Oh, i’m not mad or anything, it’s just that it seems everyone seems to take this much farther than it should be. A moving bike balances easier because the rider can readily and precisely move the contact patch from, and to, either side of the center of gravity (CG), causing the bike to fall sideways and turn (i think we all agree it turns by leaning). The only way to move the CG on a stationary bike is to pick it up and move it. Not very easy. I race motorbikes and i can tell you, it is no SUBTLE or slight push on the bars. You yank those babies and make the thing turn!
Well Bindlestiff, I played some motorcycle games today… including steering by just weight-shifting, and trying to keep the fork fixed and something new for me, countersteering w/o any weightshift…
and the verdict is… the countersteering effect is so strong it overules anything else. In short, I was wrong :smack:. (and trying to steer with a fixed fork interesting if not practical.)
And Staubej, you guys don’t just yank, you’re hanging off those bars in turns!
As far as I can tell, and my experience is only with bicycles, a quick turn to the right moves the wheels over to the right of the center of gravity, causing the bike to lean to the left. This sets you up for a nice left turn. Which seems to be Bindlestiff’s point.
In the excellent pamphlet on bicycling in traffic Street Smarts, John Allen says:
Playing around with this theory the other day confirms that it does work on a bicycle.
Well, on a bicycle, you can turn the front wheel to the side, so that pedaling forward or backward will move the bike side to side. Generally, you need either a fixed gear bike or an incline to do the backwards part. This is called a track stand, and is very useful when waiting in traffic.
Waterj2, John Allen knows a lot about it. He founded the outfit that certified me as a cylcing instructor back in the eighties.
The verbage used in teaching riders can be very difficult. The word “steer” is somewhat ambiguous and I remember the trouble it caused me when my dad was teaching me to ride. I got my first bike on my 7th birthday and Dad told me “you don’t steer with the handlebars, you just lean the bike”. It took nearly a week to get it right. The problem was that I took the word “steer” to mean “make the bike turn”. Well, if you don’t make the bike turn with the handlebars, and you do make the bike turn by leaning the bike, you must lean the bike without using the handlebars. If he had just said “…lean the bike with the handlebars” it would have come together a lot faster.
Y’know, this is one of the things I love about the SDMB. Two people disagree on something, decide on a test to see who’s right, and carry out the test. Then, one person sees that he was wrong, and corrects himself. All without hair-pulling or calling anyone a doo-doo head!
It’s ok to crack yourself up, just don’t cause yourself to have a crack-up. (just a little pun there).
Gyroscopic precession is involved but only minimally. Another test to try is to do the same test at 30 mph on a motorcycle and on a 10-speed bike. The front wheel of the 10-speed is MUCH less of a gyro but the response is pretty close in quickness to that of the motorcycle.
