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Motorcycle countersteering

By Jean-Pierre Belmonte
Promocycle


Objective

  • To observe the principal methods of teaching countersteering in rider training in Quebec. This procedure is taught to candidates as a technique for avoiding sudden obstacles.
  • To summarize the situation and make recommendations as needed.

A complex operation
Changing the direction of a motorcycle involves the interaction of several forces. Like all single-track vehicles, a motorcycle must lean in order to counteract the inertia generated by a change of direction. It is therefore necessary to initiate a lateral shift of the roll axis toward the side one wishes to go. This shift is principally created by the rider momentarily rotating the handlebar in the direction opposite to the one desired.

Correcting to control a motorcycle
With the aid of the handlebar, the rider controls the position of the contact patch of the front tire with the road relative to the centre of gravity of the motorcycle.This displacement of the front tire contact patch while in motion constitutes the key factor in leaning any single-track vehicle. Thus the direction of the motorcycle can be corrected any time it is in motion. A less significant displacement occurs because the contact patch of the front tire with the road is behind that of the steering axis. This trail provides, for a rotation of the handlebar, a lateral movement of the front of the motorcycle in the same direction as the handlebar is rotated. This displacement is constant, therefore independent of speed. It is largely used by trials riders to balance at a standstill. It is a dominant factor in steering a motorcycle only at very low speeds.

Initiating a change of direction
To initiate a change of direction, the rider uses the handlebar to offset the trajectory of the contact patch of the front tire outside that of the rear tire and opposite to the direction desired. When the appropriate lean angle is reached, the rider momentarily rotates the handlebar toward the inside of the turn before returning it to a neutral position. SEE TABLE 1

Straightening a leaning motorcycle
To straighten a motorcycle which is leaned over while making a change of direction, the rider must tighten the path of the front wheel by orienting the handlebar toward the inside of the corner. Once the desired angle (vertical for a straight-ahead trajectory) has been reached, the rider momentarily orients the handlebar toward the outside of the corner before returning it to a neutral position. This specific characteristic of a single-track vehicle requiring an initial input opposite to the desired direction, except at very low speeds, has been known for a long time. The American aviation pioneer Wilbur Wright (1871-1912) has described this steering characteristic of single-track vehicles. SEE TABLE 2.

Leaning by applying a gyroscopic force
Gyroscopic effect also plays a role in banking a motorcycle. When a torque application tends to modify the plane of rotation, gyroscopic effect produces a rotation whose axis is perpendicular to the axis of the applied torque. By turning the handlebar to the left, gyroscopic effect of the front wheel causes the motorcycle to bank to the right with respect its roll axis. Likewise, a turn of the bar to the right will instigate a lean to the left. We have examined two methods of changing the direction of a motorcycle and in both cases the initial input at the handlebar must be in the direction opposite to that desired. Happily, the effects of these two methods work in concert. They could have worked in opposition such as in the hypothetical case in which the rear wheel pivots to provide steering.

Definition of countersteering
If countersteering of a motorcycle consists of orienting, for a brief moment, the front wheel in a direction opposed to that in which one desires to go, then countersteering is the source of all significant changes of direction.There exist certain types of controllable single-track vehicles which make no use of gyroscopic effect (with blades, with skis, automobiles cornering on two wheels, two wheels with counter-wheels).

Influence of rider movement
Movement of a rider who can modify the position of his body or part of his body could technically influence a change of direction of a motorcycle. This modification of the centre of gravity of the rider-motorcycle combination has in fact only a limited effect. If the steering of the motorcycle is not articulated (i.e. steering locked), it requires a considerable distance to observe even a small change of direction caused by a shift of the rider’s body.Influence of the rider’s weight when the motorcycle’s steering is free, even if the rider does not touch the handlebar, has a greater effect than in the first case. The effect on the combined centre of gravity remains the same, but the torque generated by the rider’s movement causes the free handlebar to pivot because of its geometry in a direction opposite to that intended, thereby also providing a countersteering effect. When a rider leans toward the inside of a corner while keeping a grip on the handlebar, he pushes without realizing on the side of the handlebar which provides countersteering. In such a situation it is often easy to over-estimate the role of body position in changing direction.Changing direction by turning the handlebar influences the lean of a motorcycle by a factor proportional to the square of the speed (curve on chart above). One must subtract the contrary influence of fork trail, which explains its negative value at zero speed. It is an essential variable in the controlled changing of direction of a motorcycle. The influence of gyroscopic effect on the lean of a motorcycle is proportional to speed (sloping straight line on chart), the degree of rotation of the handlebar and the moment of inertia of the wheel. As demonstrated by the experience of British engineer David Jones in the 1970s, it is possible to control a motorcycle on which gyroscopic effect has been nulllified.Lateral movement of the rider influences lean of a motorcycle to a constant extent (dashed line on chart). This influence is not related to speed and is not significant. SEE TABLE 3

Justification of the term countersteering
The term countersteering is perhaps poorly chosen. While in automobile driving it describes a procedure for recovering from a skid, in motorcycling it refers to a procedure of initiating or creating a change of direction. Perhaps a less ambiguous term is needed.It is possible to ride a motorcycle safely over a long period without even being aware of this characteristic. Several motorcyclists who have not been exposed to recent rider training courses completed this operation successfully without being aware of it, as are the majority of bicyclists.This procedure of countersteering is taught in rider training courses as a technique for avoiding a sudden obstacle. Often, the student discovers for the first time the necessity to turn the handlebar momentarily in the opposite direction to the one desired. Certain students continue to believe that countersteering is valuable only for obstacle avoidance. The test of the Société de l’Assurance Automobile du Québec (SAAQ) for a motorcycle operator’s licence contains a specific evaluation of this manoeuvre.

A test of countersteering
In the test, a rider must avoid an obstacle 3 metres wide either on the left or the right, depending on the signal given when he is just below 10 metres from this virtual obstacle.Of the 10 metres he has available, an expert motorcyclist will take 3.5 metres for the manoeuvre of changing direction. There remain 6.5 metres in which to assimilate and decode the information (the direction of the arrow) and react to the stimuli. After accelerating, the candidate can arrive at a speed of between 20 and 30 km/h at the entry to the test. If he arrives at the minimum speed he has 1.2 seconds, compared with 0.8 seconds at 30 km/h, because the signalling of the arrow is independent of entry speed. Because the time-space for decoding and for the manoeuvre are not spelled out in the test, many candidates try to anticipate the signal and begin the manoeuvre as soon as they pass the entry gate. Each candidate has one chance in two of having anticipated the correct direction.

Results of our tests
In a series of tests we conducted using the method and instrumentation of the SAAQ, a first group of motorcyclists performed worse after having been briefed on the classic method of countersteering. A third group which had the opportunity to practise the test manoeuvre without any recommendation or theory saw its second evaluation lower than its first. Only the second group, which had been instructed to “project your torso toward the arrow while pushing,” registered an improvement in its success rate. SEE RESULTS

The problem of the wrong turn
During the tests, several riders simply turned toward the wrong side. It’s possible that incorrect anticipation of the signal explains many of the errors. However, reports indicate that there are an appreciable number of collisions in which evidence shows that the motorcyclist veered toward the obstacle instead of trying to avoid it. As underlined by the Motorcycle Safety Foundation in its Guide to Motorcycling Excellence, we must not forget that the majority of motorcyclists are also automobile drivers. With a car, to go to the right one must turn the wheel to the right, the opposite of a motorcycle. Also, in a situation of stress, it is easy to become a novice again. We see a pressing need to develop a method of training motorcyclists to act instinctively when a sudden change of direction is needed. The method currently used to teach countersteering seems not to produce an automatic response.

In search of automation
According to Daniel Willingham, a psychologist with the University of Virginia, it is possible for us to learn in an explicit way when the sequence of a procedure is explained to us in advance. We can also learn it in an implicit way by experiencing the same procedure without knowing the sequence. The two methods of learning are separate and utilize different parts of the brain.Willingham explains that when we learn to perform a series of movements for the first time, we think about the sequence in a very deliberate, and mechanical, manner. But as soon as we start to perform better, implicit learning takes over and we become more effective without even thinking about it. The part of the brain which hosts implicit learning is preoccupied with strength and synchronization. Once the system is ingrained, it becomes possible to develop touch and accuracy.

Implicit versus explicit
A problem arises from the fact that under conditions of stress, the explicit system takes control over the implicit. This is the state of a person who freezes, or “chokes.” At this precise moment, we become novices again. Stress also tends to erase short-term memory.One can imagine that for a motorcyclist who performs habitually such changes of direction in an implicit way, having to then follow an explicit instructional sequence, to “push where you want to go,” adds a step to the thought process and lengthens the operation.

Dead foot, dead engine
In moments of intense stress, concepts as simple as left or right canbecome difficult to assimilate. In emergency situations it is best to avoid them altogether. In the aviation world, the loss of an engine on a multi-engine plane demands precise and rapid action from the pilot. He cannot ignore the dead engine because it exerts excessive drag that compromises the stability of the aircraft. He must determine which side has the dead engine, identify and follow procedures to reduce the drag. On an aircraft with variable-pitch propellers the procedure is to feather the dead one. The propeller blade is set parallel to the airflow in order to minimize its drag. Application of this procedure to the wrong one, that is, to the engine still operating, would be catastrophic. The lack of propulsion from the dead engine makes the aircraft tend to pivot in the direction of the dead engine. To maintain his heading the pilot must compensate by using his feet against the pedals controlling the rudder. To identify the side on which the engine has failed, the pilot recalls the phrase, “dead foot, dead engine.”

Recommendations
We recommend fine-tuning a process of automation based on a phrase or a slogan of a few words which will recall and identify the steps to follow. This automation will make reference to vision, specific action at the handlebar and overall action of the motorcycle. It must have key words which will define the steps for collision avoidance. Those key words and the procedures they describe can be repeated until they become automatic. At the testing level, we recommend separating the time-space for decoding the signal from that of the manoeuvre in order to prevent any degree of anticipation. We recommend that the test be conducted at least twice for each candidate. We recommend that the stimulus or signal be negative, that is, that it symbolize something to be avoided rather than to indicate a direction to be followed. It should not be placed on the ground, but rather at a height to be determined, and should be synchronized with the entry speed which should be at least 25 km/h. The approach distance should be sufficient for the candidate to stabilize his speed.

More than 50 delegates from the FMQ took part in the presentation of the report on countersteering at the PMG Technologies test centre at Blainville, Quebec, on September 15, 2001.

 

Jean-Pierre Belmonte, president of Promocycle, during the conference on countersteering.

 

A practical demonstration of gyroscopic effect.

 

Participants in this conference could see a preview of the 2002 safety event on the theme of braking.


Friendly discussion or storm brewing?

 

Copyright – Promocycle 2008