Established Since 1994
RT3 Grip Brochure

To measure road or runway surface friction all RT3 units use a patented GEM (Grip Evaluation and Management) force sensing hub and control panel. Ballast weight is used to create a constant force between tire and road or runway surface. This innovative technology has few moving parts, is robust and very accurately measures friction levels. This technology has been extensively tested by numerous transport agencies worldwide and has recently been accredited by the FAA for runway surface friction measurement (see the “RT3 Flight”). Each RT3 variant uses the Halliday hydraulic module which will automatically elevate and deploy the measuring wheel when required.

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RT3 Grip
PATENTED DESIGN FORCE SENSING GEM HUB CONTROL PANEL
  • The force sensing GEM hub monitors changes in lateral friction force between the RT3 tire (or tires on the RT3 Curve) and the road or runway surface.
  • This surface friction data flows from the GEM hub inside the friction measuring wheel to the in cab control panel. The control panel displays the friction value directly and continuously to the vehicle operator
  • From the control panel, the friction values can also be transmitted to an in cab laptop and/or sent via a Bluetooth connection at the control panel to a PDA which displays the data
  • The PDA in turn can send the friction and location data real-time to a remote website for viewing by management staff
  • The RT3 measures the friction with a single load cell located in a compact single hub design with all working components fully protected from outside elements. This high resolution load cell is protected against overload with a series of mechanical stops. The stainless steel hub contains very few moving parts and has proven extremely reliable over multiple years in the demanding dirty and corrosive environment of winter roadway maintenance.
  • Ruggedly designed for use on winter highways, many of the components are manufactured in stainless steel. This new technology is a breakthrough in road and runway surface friction measurement and ensures reliability, accuracy and longevity of use.
RT3 Grip Versions
RT3 Grip Versions
  1. The friction force between the tire and surface is directly measured at the GEM hub by a single high resolution load cell placed in the axial force measuring direction.
  2. This force signal is amplified at the hub and then sent to the in cab control panel via a hard wire
  3. Unlike all other CFMEs, the RT3 does not use any exposed belts and pulleys but instead uses the GEM hub which also measures distance travelled.
  4. All of the working components in this GEM hub are fully protected from the outside elements
  5. The load cell is protected against overload with a series of mechanical stops.
  6. The stainless steel hub contains very few moving parts and has proven extremely reliable over multiple years of continuous use.
This device is proven to record changing friction levels in great detail with a high degree of repeatability. In extensive testing, the Swedish Government established that some meters (not RT3) showed a high degree of repeatability but were unable to detect significant changes in surface friction i.e. they had very poor sensitivity. The RT3 proved to be the only meter during these tests that showed both high sensitivity & high repeatability allowing the RT3 friction readings to align with the surface conditions.
(See reports for published results of these tests).
RT3 Grip Versions
UNIQUE CONTROL PANEL FEATURES
  1. The custom display unit is the operators interface with the GEM hub force sensing hub.
  2. The roadway surface friction value is continuously displayed to the vehicle operator through the alpha numeric & LED displays providing clear and detailed immediate feedback of road and runway surface conditions.
  3. The brightness of the display is adjustable.
  4. The operator can select how frequent the control panel will display data from the hub, even though the hub continuously samples friction at 100 hertz.
  5. The wheel is hydraulically elevated and lowered directly by pressing a button on the control panel
  6. A marker button can be used to indicate a noteworthy single test detail marking condition and location.
  7. The data from the force sensing hub is relayed continuously to an in cab control panel and can also be simultaneously fed to a laptop which graphs the friction result.
  8. Data can be graphically displayed in imperial or metric units
  9. The data can also be directed to a remote site, such as a web site via a mobile device (PDA), if desired
  10. From this friction data, a color coded (red/yellow/green) map can be created showing road friction real time.