Development of Methodology to Determine Toe Geometry of any Vehicle at Its Early Design Stage for Optimum Tyre Life

Toe setting is one of the major wheel alignment parameters which directly effects handling of a vehicle. Correct toe setting ensures desired dynamic behavior of an automobile like straight line stability, cornering behavior, handling and tire durability. Incorrect setting of toe during design stage significantly deteriorates tire durability and leads to uneven tire wear. In the present scenario of automotive industry, toe setting is majorly an iterative or a trial and error process which is both time consuming and involves higher development cost as there may be instances where 2 to 3 sets of iterations are needed before specification is finalized for production. Therefore, determining optimum toe setting at an early stage of a product development will not only save significant development time but it will also benefit in reducing product validation time and cost. Through this paper an attempt has been made to develop a methodology for deciding toe setting for any vehicle as a first time right approach to cut down on conventional expensive & time consuming iterative approach. In this new methodology a detail study is carried out on different vehicle kinematic parameters as described in the latter section of the journal (aspects like bump steer, cornering behavior, braking and toe compliance [2, 3, 4, 5]) and finally a mathematical equation is derived from these values to determine desired toe setting which will enable meeting optimum tire wear characteristic of any vehicle. Results obtained from the field on a test vehicle indicates a good level of correlation with the mathematical equation thus significantly validating this methodology. Same methodology is applied to other platform vehicles while deciding vehicle wheel alignment specification at their design stage and the results indicate a horizontal deployment of the methodology.