<div class="htmlview paragraph">The most effective way to improve the driver's road feel at high speeds is to increase the stiffness between the steering wheel and the vehicle's wheels at times when only a small amount of steering effort is required.</div> <div class="htmlview paragraph">Though rack and pinion steering systems have good features in this respect compared with recirculating ball steering systems, which have been commonly used in Japan and the U.S.A., we are studying ways to improve the stiffness of rack and pinion steering systems by analyzing the effects of each parameter on stiffness. The effect of the stiffness of rack and pinion steering gears on overall automotive steering systems is analyzed here based on actual vehicle tests, which naturally include the stiffness of the vehicle's wheels on the road.</div>