Do they Work?

Examples of success.

On occasion, it has become apparent that an incompatibility existed between tyre stiffness and the suspension set-up required to control a high downforce vehicle. In such cases, the efficiency of the suspension can be improved either by reducing spring stiffness or by increasing tyre stiffness. If a lower spring stiffness is not an option, then it is worth trying an increased tyre stiffness. Increasing rear tyre pressures by 7 psi in one example resulted in a lap time reduction exceeding 2 percent; in another example adopting a stiffer construction tyre resulted in a similar improvement in lap times. (As an aside, it is worth noting that changing tyre pressures will also affect the work done by, and hence the heat input to, the tyres. The resulting change in tyre temperatures can, depending upon the tyre design, affect performance dramatically and outweigh any benefits brought about by improved vehicle control. Track tests are definitely required to assess the effect of tyre pressure changes suggested by a rig test.)

It was the fashion in one junior (non-aerodynamic) formula to use pre-loaded springs so that the suspension moved only when large forces were applied to the wheels. This strategy was, apparently, used by all teams so that any reduction in performance was not obvious. One race team booked a rig test. During the test the team was encouraged (not without some resistance) to reduce preload so that the suspension actually worked for most of the time. Minor adjustments were then made to optimise damper settings. The change in strategy proved to be so successful that, due to a misinterpretation of the team's explanation, damper homologation was introduced into the series at the start of the following year.