How do you steer a motorcycle? This is the most basic skill everyone learns in their 2 wheel training, starting with that first bicycle, and yet knowledge of countersteering is often completely lacking or misunderstood by many riders. If you want to get a good debate going in any group of riders, ask about countersteering. It might be a better debate generator than talking about torque versus horsepower, and we all know how those debates go.
Keith Code, who runs the excellent California Superbike School, figured the best way to end the debate was a demonstration. He built a bike he calls the “No BS Machine” where he installed an extra set of handle bars. The bars are solid mounted to the frame, they do not move the front wheel in any way but are simply a place for your hands with a throttle to maintain speed. Riders are then given an opportunity to try turning the bike with any amount of leaning, weight transfer or body english they desire so long as they are holding on to the solid mounted bars. The result? The bike continues forward in an uninterrupted straight line. It may wobble or do any number of weird things but it doesn’t turn.
Keith Code never mentions anything like gyroscopic precession to explain any of it, he simply says here’s the demonstration. He leaves the technical debate to others. It sounds like a great bike to add to basic motorcycle safety courses around the country. It’s the kind of thing that could save someone when they drift wide into oncoming traffic and have to react fast. Just remember, push right – go right, push left – go left.
Thanks Bob, for the pointer.
Ride says
I always crack up when talks of counter steering arise. It is the only way you can turn a bike so it comes naturally. To have to think about it seems moot. Then again I have been riding bikes for 30 years so i guess it is not all that obvious to noobs.
Dummy says
The only way the no BS bike doesn’t change direction is if the front end is locked, so the forks can’t rotate on the steering axis. Otherwise, shifting weight does make the bike change direction because it causes the forks to rotate on the steering axis.
So, by forgetting to mention that the front end needs to be locked into position, so the forks can’t rotate around the steering axis, Code’s “no BS bike” is all BS.
PigIron says
There are no “noobs” as everyone learns instinctively when they first ride a bicycle.
I must say though that the amount of counter steering needed to initiate a turn is practically imperceptible. If you push hard you just waste time bring the bars back after you start to lean. And after you start leaning weight shifts etc… make a lot of difference.
coho says
Code seems to have a knack for inventing (or at least adapting) interesting ways to demonstrate motorcycle dynamics to believers and unbelievers alike.
Nothing like a visual:
http://www.youtube.com/watch?v=3nRUeEkS644
discontinuuity says
I’m able to make wide turns with my bicycle with no hands on the bars; it isn’t really that hard as long as you’re careful. Am I missing something here? Did he lock the fork in place?
Ride says
If the fork was locked into place you would crash ASAP as you could not balance. I too have steered my superhawk with no hands on the bar. It takes a lot of leaning and it is a big arc but it can and is done.
RH says
The forks are not locked on this bike in any way.
RH says
Millions know how to ride – few know the physics involved. And the physics of weight shifting are the same no matter if the bike is cranked hard over or straigh up.
pghcyclist says
wait a second here. This doesnt make sense. How come i can take my hands of the handlebars and turn my bike just fine by leaning. thats the whole point of fork rake and steering angles. I have seen plenty of stunters abusing their machines and doing all sorts of stuff just by shifting their weight. manybe i missing the point here, but i dont buy it. Yes if your upperbody is locked its harder to shift your weight. Try grabbing the windsheild and steering its alot harder but you can still do it.
Blair says
I’ve heard of a similar example, except instead of extra bars they just cranked the steering nut up until it wouldn’t move. Then they challenged people to turn corners on it, which they found very difficult.
I was pondering it all one day while I was riding, I tried gently swerving from side to side whilst staying in my lane. Without even thinking about doing it I found I was applying pressure to countersteer which was initiating the movement. No mass transfer required.
The old trick of holding a spinning wheel and moving the axle forward is usually helpful too. If those watching can get their head around it that is.
Brian says
Code’s bike in NOT BS. It’s just a simple learning tool to help riders realize the effect counter-steering has on a bike. What you learn from it is how to emphasize this instinctive counter-reaction and turn it into a controllable technique to improve your riding.
Push with your right hand, and the bike will immediately lean right. Push with your left hand and the bike will immediately lean left.
At the core, a bike’s lean angle is just the balance of two forces: centrifugal and gravity.
Of course you can nudge your bike in a certain direction with no hands. But only after the steering mass has flopped over due to a change in the bike’s angle. But how in the heck will that improve your cornering?
Here’s a better video with stick figures:
http://www.youtube.com/watch?v=C848R9xWrjc
Dummy says
It doesn’t turn because the front forks are locked. If the forks are allowed to rotate on their steering axis the bike can turn like this:
(of interest is 1:55-2:15)
http://www.youtube.com/watch?v=xBw0yH509lw
RH says
THE FORKS ARE NOT LOCKED.
guitargeek says
Everybody knows that countersteering only works on shaft drive motorcycles, and only in the Northern Hemisphere.
Scott says
As RH and Brian have intimated, it is the most basic of physics problems; the only way a motorcycle can turn is to provide an equal and opposite force to the centripetal force, otherwise the bike falls over. Therefore, a left turn requires a small turn to the right which moves the contact patch to the right respective to the rider/bike mass. Resolving this lean angle into X and Y components exposes the horizontal component of the weight, which is the force opposing the centripetal force. Yes, it is possible to turn a bike by moving your body to create a lean angle, for exactly the same reason as stated above, it just isn’t as easy or efficient to move your mass around as it is to flick the bars.
Brian says
Dummy, (no insult, that’s apparently your screenname) the forks are NOT locked on Code’s learning bike, and that’s not the point of this discussion anyway. If they were locked, how would the rider ride the bike out to the spot where he switches his hands?? Plus, I’ve seen the NO BS bike and they’re clearly NOT locked.
2.) The stunt rider in the video you referenced is moving slow, therefore gyroscopic force will not prevent the front wheel from flopping around as much. I don’t think anyone would disagree with the fact that a bike’s front end WILL move around MORE the SLOWER you go. QUICK cornering at HIGH speeds requires you to PUSH with your hands to counteract gyroscopic force. Of course wide sweeping turns are possible as higher speeds. But you try that theory next track day and see how far you get.
3.) Watch closely to the stunt rider when the bike is upright, arms stretched out. HE even kicks the bike to the opposite direction in order to get the bike to lean the OTHER way. Once he’s leaned over, the weight of the front end past the steering axis keeps the bike in a turn. Based on the weight and chassis geometry, there’s only ONE angle and ONE speed this will work for. Anyone who’s ever ‘ghost ridden’ their BMX bike as a kid has observed that.
Thanks for the video, because it proves you don’t even need hands to witness counter steering.
Brian says
Now THAT is funny guitargeek.
Brian says
Scott, I’ll agree, but keep in mind the force of gravity is your friend in this situation. So when you lean, the point at which you stop leaning is really the balance of these two x and Y forces. The whole reason it’s a ‘lean angle’ in the first place is because of the force of gravity added to the mass of the bike, right? In a vacuum, without gravity, you’d have to lean completely parallel to, or 90deg over, to counteract the centrifugal force pulling you to the outside.
RH says
Guitargeek must be right – I can’t find any Youtube videos of motorcycles riding across Antarctica!!!!
JC says
I too can steer both bicycle and motorcycle with no hands, but I suspect that what happens is that the weight shifts cause the steering to flop to where we want it too! It doesn’t take a big steering angle change to make the wide arcs we’re talking about here, so maybe it isn’t noticeable.
machinerage says
I don’t care much about the physics of countersteering. All I know is that it works. Sure, there are ways to make a bike change direction at low speeds. And, there are ways to make a bike change direction at high speeds. But, the only method you need to know is called countersteering. To the nonbelievers: initiate a turn deliberately using countersteering and you’ll understand. It’s all about the turn in.
Tanshanomi says
If you look at the No-BS-bike video on the Superbike School’s website, the rider does manage to generate some wide, gentle, wandering turning movements with the bike. (Notice, at the end of the first demonstration, how he even manages to follow a bend in the track by constantly jerking his weight to his left.) I don’t think anybody is saying that weight shift has ZERO input into steering. But it’s just a small a fraction compared to the agility of countersteering, and certainly not enough to get you through traffic by itself.