Overview of K&C Testing

The Morse Measurements K&C test machine – the first of its kind to be independently operated and made publicly available in North America – grabs your vehicle chassis from the underside and can move it in vertical Bounce, Roll, and Pitch. The tires stay in contact with a level “road plane” at four individual wheel pads. These wheel pads can maintain zero scrub force (through continuous feedback force control) -or- they can introduce ground level forces to simulate braking, acceleration, and cornering loads at the tire contact patches. Precision digital encoders and load cells measure tire loads and wheel orientations at all times.

Remember, all these forces and displacements are applied slowly (quasi-statically) to capture suspension force-displacement relationships and friction. By measuring all these things at Morse Measurements – where everything is accessible and repeatable – you can reduce a lot of the guesswork (and costs!) associated with on-road/track test sessions.

K&C testing is not really “dynamic” testing at all – although it has a very close relationship to vehicle dynamics. K&C tests are quasi-static – all loads and displacements are applied quite slowly. This is done purposefully to look at force-displacement relationships and friction in the suspension. The AB Dynamics K&C test machine at Morse Measurements is specifically designed to displace and load a test vehicle in our facility in ways that would be very difficult to do otherwise.

If you are already familiar with suspension K&C testing, you already know its usefulness. You already know that it is an invaluable tool for chassis builders, suspension designers and tuners, and for supporting/validating/feeding vehicle dynamics computer models. If K&C testing is relatively new to you, you might ask: Practically speaking, how is K&C testing going to help me?

One resource for answering such questions is the technical paper titled Using K&C Measurements for Practical Suspension Tuning and Development (SAE paper # 2004-01-3547). You can purchase this paper at http://papers.sae.org/2004-01-3547/. The paper covers some of the basics of K&C testing and talks about some of the practical ways to use K&C data for racecar suspension set-up. The description below steps through some of the basics of K&C testing.

Another SAE paper of interest is titled Suspension Geometry: Theory vs. K&C Measurement (SAE paper # 2008-01-2948). The paper discusses theoretical suspension geometry as compared to actual measurements made on the K&C test machine. This paper is also available for purchase from the SAE at http://papers.sae.org/2008-01-2948/.

K&C testing answers a number of questions commonly posed by racers and production car engineers.