The essential
Mount the tires on the rim adapters, bolt the adapters to the transducers at the specified torque, balance the assemblies and fit them to the vehicle. Hold each slip ring stator rod vertical. Power the interface boxes, run the shunt calibration, then zero with the vehicle on a hoist while each wheel turns two revolutions. Finally set the measurement origin, the coordinate system and the outputs on the embedded web page.
How is the wheel assembled?
Install the tires on the rim adapters, bolt the adapters to the transducer at the torque for your model and adapter material, then balance each transducer and tire assembly before fitting it to the vehicle.
- LW12.8 models, M10 bolts with solid or two-piece aluminum rim adapters and stainless steel or titanium hubs: 81 N·m.
- LW12.8 models, 3/8 in bolts: 54 N·m into aluminum rim adapters, 68 N·m into stainless steel or titanium hub adapters.
- Welded aluminum rim adapters: 37 N·m.
- For other models, the tightening torques are in the manual.
How is the stator held?
With the slip ring stator rod vertical, held from the vehicle body or corrected for steering.
- Non-steered wheels: the magnetic restraint (MVSR) on the body, reinforced with tape.
- Steered wheels: the stator angle correction device, an over-the-wheel bracket, or the correction equations of the manual.
- If vertical is not possible, measure the rod angle and enter it on the web page of the interface box.
How are the interface boxes powered and wired?
The CT2 boxes stack, and one power cable feeds the whole stack from 9 to 36 V DC.
- The white wire is power high, the black wire is ground.
- Route the slip ring cables into the cab and connect them to the boxes.
- Power on, press MODE to enter set-up mode and set the Position of each box to the location of its wheel.
How are the shunt calibration and the zero run?
Shunt calibration first, then zero on the hoist, both before any recording.
- Press SHUNT: the shunt calibration runs; the fault light should not come on.
- Hoist the vehicle, press ZERO and rotate each wheel two revolutions.
- With the angle correction device: zero it too, by holding its button for 2 seconds with the stator rod vertical and the wheels straight ahead.
- Then switch the boxes to RUN mode.
Which checks are run on the track?
One check per force on each wheel: a static reading for Fz, then two short runs for Fx and Fy.
- Static weight on Fz: with the vehicle at rest, each wheel reads the load it carries.
- A coast-down on Fx: checks the sign and the order of magnitude of the longitudinal force on each wheel.
- A slow circle on Fy: checks the sign of the lateral force on each wheel.
What is set on the embedded web page?
The measurement origin, the coordinate system and the outputs. Connect an Ethernet cable between any box and a laptop set to the static IP address 192.168.0.100, then open 192.168.0.28 in a browser. No software is installed.
- Measurement origin: enter the value a to move it to the tire center or to the hub face, and leave RR at 0. For the same change on all four wheels, tick Update All.
- Coordinate system: the right hand rule is usually preferred.
- CAN output: set the baud rate, the output rate, the units (metric or English) and the termination (one per bus), check that all message identifiers are unique, then save the .dbc file.
- In the data acquisition system: load the .dbc file, set the same baud rate and sample rate, and turn the termination resistor on.
- Analog outputs: set the acquisition from the quick reference calibration sheets supplied.
How is the measurement origin moved afterwards?
In post-processing, with the equations below. With a the distance from the default origin plane to the desired one and RR the rolling radius of the tire, the forces do not change: Fx = fx, Fy = fy, Fz = fz. The moments do.
- Right hand rule, right side of the vehicle: Mx = mx + fz·a − fy·RR ; My = my + fx·RR ; Mz = mz − fx·a.
- Right hand rule, left side: Mx = mx − fz·a − fy·RR ; My = my + fx·RR ; Mz = mz + fx·a.
- Default left hand rule, right side: Mx = mx + fz·a + fy·RR ; My = my − fx·RR ; Mz = mz − fx·a.
- Default left hand rule, left side: Mx = mx − fz·a + fy·RR ; My = my − fx·RR ; Mz = mz + fx·a.
All signals stay at zero?
Rotate the wheels, on the hoist or by driving. After a power cycle, the interface box holds all signals at zero until it has seen the index pulse of the encoder.
Documents to download
To remember
- Torque the adapter bolts to the value for your model and adapter material.
- Stator rod vertical; correct the angle on steered wheels.
- Shunt, then zero on the hoist with two wheel revolutions.
- Origin, coordinate system and CAN settings are on the embedded web page.
Updated October 2026, from the quick guide rev. 1.0 for LW12.8 transducers with CT2 interface boxes. The manual of your model prevails.