The RT3® is designed to reflect a small vehicle cornering at all times as the measuring wheel travels across the surface. We achieve this by measuring lateral friction applied to a load sensor by adding a small toe in angle to the measuring wheel(s). The GEM hub sensor measures the lateral force on that tire as it moves across the surface.
On a high friction surface, the corresponding Mu Value is higher. On a low friction surface, the Mu value will be much lower. We use a scale between 0-1.
With such a small wheel angle, the RT3® can run without a water system year round without significant degradation to the tire. If more wheel angle is required, that can be accommodated by the RT3® design, but the tire might build up heat which will change the properties of the rubber compound.
Understanding the parameters of the testing process and working to eliminate all variables outside of those you want to test is critical to understanding the true friction value of that tire running on that surface in those conditions. While we would like measuring friction to be simple topic, sometimes it can be a four dimensional problem to solve.