4.3 Stability of 3-Wheelers with two driving-steering front wheels:

The present section 4.3 first presents the mathematical calculations of safety margins against rollover, in the case of 3-Wheelers with two front driving-steering wheels.
Next, it presents the mathematical calculations of safety margins against 'rolling' or tipping forward when braking hard,  in the case of these same 3-Wheelers.

These mathematical developments are based on and go beyond the development presented in the document:
"Evaluation of Electric and Hybrid 3-Wheeled Vehicles for Handling and Stability", Paul G. Van Valkenberg, Richard H, Klein, Henry T. Szostak, System Technology Inc. 13766 South Hawthorne Boulevard, Hawthorne, CA 90250, Contract No. DOT HS-9-02309, Sept 1981, 115 pages.

More precisely, the development by Valkenburgh-Klein-Szostak above does not consider the Front Inner Wheel Slip phenomenon (FIWS or in French: Glissement de la Roue Avant Interne GRAI) of 3-Wheelers with two front driving-steering wheels: If such a 3-Wheeler accelerates while turning, the front inner wheel towards the interior of the curve will be lightened by the weight transfer towards the outer front wheel (due to the lateral acceleration) and will be lightened by the weight transfer towards the rear wheel (due to the longitudinal acceleration). So the front inner wheel will not be able to support the high lateral and longitudinal accelerations. This will reduce the chances of rolling over the 3-Wheeler. The safety margin against rollover of this 3-Wheeler will thus be higher than calculated by Valkenburgh-Klein-Szostak above.

Section under construction:

The rest of this section has not yet been completed in English. The reader is asked to go to the French version.

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