Choose Racing Springs You Need with Racing Car Technology's Bounce Test™

Uncategorized Feb 06, 2020

In the video, I am showing you how to measure the stiffness of your race car suspension using our Racing Car Tecnology Bounce Test™. It's an exclusive procedure I developed over twenty years ago and have used consistently ever since for quickly and easily setting up race cars.

Measuring "CPM" in the Video

At about 1.00 minute into the video, you can see I have measured 61 bounces in 30 seconds. So, for this Triumph TR3 race car, the front suspension frequency is 122 CPM for the known 550 lb/in springs fitted. If we wanted to go to 130 CPM, for example, we can calculate what stiffer spring rate is required to get that.  

What is Suspension Frequency? 

We are determining the suspension stiffness in terms of the "suspension frequency" - the undamped natural frequency of the suspension, measured in CPM (cycles per minute), sometimes shown as Hz (cycles per second).

The procedure works for all non-coilover suspensions where we can remove the shock absorbers to do the test. (For coilover suspensions we cannot use the Bounce Test ™ , but we can measure accurate motion ratios and work out the suspension frequency as nomally recomended in the suspension set-up literature.)

What we are after with measuring suspension frequency, whether via the Bounce Test™ or by measuring the motion ratio, is to calculate the spring rates we need to achieve our desired suspension frequency for front and rear suspensions.

The Bounce Test™ fills a huge gap in suspension set-up practise. Up 'til the Bounce Test,™ choosing springs needed for racing for non-coilover race cars has been mostly guess work.

Using CPM in Suspension Set-Up

For low or non-aero race cars, at Racing Car Technology, we have found choice of the suspension stiffness is the most important setting on the car for improving grip at the tyres and thereby optimizing performance.

Getting the CPM right is the single biggest improvement you can make to your race car, the single biggest contributor to optimizing track performance.


Now you can get a perfect handle on what you need for setting up the suspension on your own race car with Racing Car Technology's online training programs. Here you learn a treasure trove of hard won information and tips on the suspension frequency and calculations with the Bounce Test™ and with motion ratio measurements. We've added a new dimension to spring selection for production race cars and open wheeler and sports racing cars alike. 

Here you can see an overview of our full set-up procedure at Racing Car Technology....

Get this free report: "Our Racing Car Technology BLUEPRINT for Getting a Great Suspension Set-Up."