The essential
Size the transducer on the peak vertical load of the heaviest axle with margin, not on the static corner weight. Then let the rim, the signal path and the test duration settle the rest. Capacity classes run from 15.5 kN (motorcycle) to 445 kN (Class 8 tractor) and 700 kN (LW700, very heavy vehicles); passenger cars and SUVs use the LW12.8-50 (50 kN) or the LW65 (65 kN).
What is the peak vertical load?
Start from the heaviest loaded axle and the events you will drive. On the front wheel of an SUV, a pothole at 40 km/h (25 mph) lasts less than 0.5 s, and the largest radial force comes when the wheel strikes the far edge. The capacity class follows.
- Motorcycle: LW-MC-3.5K, 15.5 kN. ATV and small vehicle: LW9.5, 35.6 kN.
- Passenger car and SUV: LW12.8-50 at 50 kN, LW65 at 65 kN and 10.5 kN·m.
- Heavy SUV and pick-up: LW-2T-20K, 90 kN. Medium duty: LW-2T-30K, 133 kN.
- Heavy duty and Class 8: LW-2T-50K, 60K-S, 100K-S, 222 to 445 kN.
- Very heavy vehicles, hubs with a 425 mm bolt circle: LW700, 700 kN.
Which rim and which hub?
The transducer replaces the wheel center, so the rim must be modified and a hub adapter made. Send the wheel drawing, bolt pattern, center bore and offset: the adapters are made to keep the original offset.
- Original offset kept, or the track width changes the loads you measure.
- Minimum rim size depends on the model: 12 in and larger on the LW65, from 10 in on the TW9.5 wheel torque transducer.
- Unusual patterns, motorsport or agricultural wheels: custom adapters or a custom transducer.
How does the signal leave the wheel?
By slip ring, which also carries the encoder for wheel angle and speed, or by telemetry when no cable can leave the hub. The two packages are swappable on the same transducer.
- Slip ring: the default. Wired, unlimited bandwidth, encoder options 60, 256 or 512 ppr.
- Telemetry: LW12.8-50-TEL for cars and light trucks; a wheel package on a 9 V battery.
- Either way, the interface box uses the wheel angle to resolve the loads into vehicle axes and corrects the crosstalk, in real time, with analog and CAN outputs.
How long and where?
Days on a proving ground, weeks on a durability loop, or a season off-road. Water, dirt and the brake heat reaching the hub set the sealing and the checks.
- Rain, snow, mud, salt: weatherproof slip rings; the transducers are sealed to IP67.
- Long descents heat the hub. The transducer is temperature compensated, but check the zero before and after each run and log the transducer temperature.
- Rental for one campaign, calibrated before shipping, or purchase for a fleet.
What comes with it?
Each unit ships with its calibration matrix and certificate by serial number. The matrix corrects the crosstalk between the six components, so use the one that belongs to that transducer.
- Matrix and certificate per serial number, ISO/IEC 17025 calibration.
- Recalibration after the first year of use, then at least every two years, and after an impact.
- Mounting instructions, torque values, wiring diagram and channel list.
To remember
- Peak load with margin, not static weight.
- Rim and hub decide the adapters; send the wheel drawing first.
- Slip ring by default; telemetry when the hub cannot take a cable.
- One calibration matrix per serial number: keep it with the data.
Updated October 2026. Capacities from the published range.