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5.6 Lateral shifting out of the body:

5.6.1 Contribution:

- In motorcycle and mountain bike races, the body lateral shift towards the interior of the curve helps going faster.

- At slow speeds on a motorcycle in a parking lot or on a bicycle when turning around in a narrow path, the body lateral shift towards the exterior of the curve helps turn more tightly and safely.

5.6.2 Limits:

- The body lateral shift does not explain how a 2-Wheeler is steered. It's simply a technique that help steer 2-Wheelers.

- Furthermore, the body lateral shift is not done on the same side at low and high speeds.

5.6.3 Better understanding of lateral body shifting:

a) Effect of body lateral shifting towards the interior of the curve, on a motorcycle:

In motorcycle races, the body lateral shift out towards the interior of the curve, with a knee hooked to the tank, helps lean the tires less versus the road in order to get better grip and go faster. Furthermore, the other knee extended out and nearly touching the road gives the rider cues about how close he is to the ground, in order to better control his motorcycle leaning angle.

b) Effect of body lateral shifting towards the interior of the curve, on a bicycle:

In mountain bike races, the 2-Wheeler chassis leaning less helps the front wheel work and 'plough' better in the gravel of the road, in order to be able to avoid going out in a curve where there often are dangerous rocks and trees.

c) Effect of body lateral shifting towards the exterior of the curve at slow speed:

On a motorcycle at slow speed such as 25Km/h in a parking lot or on a bicycle when turning around in a narrow path, the body lateral shift towards the exterior of the curve helps the arms turn the handlebar more, without letting go of the grips. It also helps leaning the 2-Wheeler more, which further increases orientations of the front wheel, through the 'wheelbarrow' effect, in order to turn more tightly.

The 'wheelbarrow' effect occurs when leaning it towards where we want to go: It's not the lateral CG shift towards the center of the curve that causes turning since there is no 'steering' difference between loaded and unloaded wheelbarrows. Leaning the wheelbarrow along an axis going from the hands to the wheel-ground contact point, simply lets the front wheel be oriented towards the interior of the curve to insure turning.

The lateral body shift towards the exterior of the curve below 25 Km/h is thus useful, but it does not explain the 2-Wheeler stability at such speed. We still have an unstable vehicle on only two wheels. Besides, the body can stay shifted to one side at such low speed and we can let go of the handlebar. If the speed is lower than the minimum stable speed WITH hands on the handlebar, the body lateral shift will certainly not hold up the 2-Wheeler. It’s the simple fact of putting the hands on the handlebar that keeps it up and stable by magic (when the Torso-Arms-Handlebar is unknown).

d) Knee extending out and catching in the wind:

At high speeds (above 160 Km/h - 100 MPH), the knee extended out towards the interior of the curve catches in the wind and exerts a drag that can alone steer a motorcycle in a long curve.

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