Next the tire stifness is increased by a factor of 10. As seen in Figure 10-18, the resulting suspension is seen to provide significantly reduced tire deflections and hence better road holding and cornering performance. However, as seen in Figure 10-16, this is obtained at the cost of increased sprung mass accelerations due to roll-off of the sprung mass acceleration transfer function occuring at a higher frequency. The suspension deflection performance is similarly worsened at high frequencies (Figure 10-17) due to the increase in unsprung mass resonant frequency.
Figure
Let us briefly consider the case where the tire stiffness is kept the same, but significant tire damping is introduced. The increased tire damping will reduce the resonant peak of the sprung mass acceleration transfer function at the unsprung mass resonant frequency. The suspension deflection and tire deflection transfer functions will also be improved at the unsprung mass resonant frequency. While these are all desirable, increasing the tire damping is non-trivial. Hence these beneficial effects cannot be physically realized.