Suspension Set-Up For Drivers....

My talk on suspension setup with Samir Abid is now live on the Your Data Driven Podcast. Listen in here:

To find out how to choose spring rates (spring stiffness) for your race car, click the link below. You can calculate the "suspension frequency" (suspension stiffness at the tyre contact patch)hat will give you best grip at the tyres for your particular race car.

Vehicle Dynamics for Drivers

 In cornering, racing drivers are greatly dependent on their “feeling", their sensitivity for what the race car is doing.  

But one problem that’s been around over the history of racing - drivers have difficulty explaining what it is they are feeling from the car. For example... What are the involuntary steering adjustments the driver makes when cornering? How does the racing driver do this without conscious thought? 

In finding answers, new information from the field of cognitive science show us what's involved learning the skills you need in motorsport. Expert learning works through deliberate practise of the skills. In this learning and development process, the subconscious brain has an innate ability to select which sensory inputs to take into account, and what mental processing is required. The racing driver is not consciously aware and cannot get all the details on this, just by thinking about it.

However, by looking at the physics of what is happening at the tyre contact patch, the vehicle dynamics, we can get a handle on what the racing driver is feeling.

A Visualisation of Car Control and the Body Slip Angle

The “body slip angle” is the angle between the vehicle centre line and the vehicle direction of travel. There is a geometrical relationship between the slip angles at the tyres and the body slip angle, where peak body slip angle represents peak grip at the tyres .

We need to reframe how we think about the race car in the corner entry.

Starting from zero body slip angle at turn in, as slip angles build at the tyres, the chassis rotates slightly, while the tyre contact patches continue to grip the road. See body slip angle β in the middle diagram.

If peak tyre slip angle (max. grip) is exceeded at the rear, then the car goes into oversteer and the body slip angle is ever increasing.

“Most drivers are acutely sensitive to the rate of change of body slip angle.” Damian Harty, Vehicle Dynamics Engineer and Author.

When you get into this, it's becomes apparent that what we know as the racing driver's car control is a completely seperate skill compared to the overall task of navigating the track and guiding the race car.