A wheel clamp creates the mechanical connection between the wheel and the measurement target; any movement in that connection can appear as wheel movement.
Correct size range matters as much as clamp style.
All contact points must seat consistently.
Target holders must lock without play.
Compensation addresses mounting eccentricity, not a loose clamp.
The clamp is part of the measurement chain
The aligner calculates wheel position from the target. The target is attached to the clamp, and the clamp is attached to the wheel or tire. If any interface shifts, the camera cannot know whether the wheel moved or the mounting hardware moved. This is why clamp installation is a measurement task, not only a setup task.
Contact geometry and repeatability
Rim-contact clamps use jaws or pins at defined points on the wheel. Correct engagement requires the clamp to be within its rated diameter range and the contact points to seat on suitable surfaces. Uneven engagement, decorative wheel features, corrosion or excessive force can disturb centering or damage the wheel.
Rigidity during the complete workflow
The mounting must remain stable during rolling compensation, caster sweep, steering centering and adjustment. Cable pulls, technician contact and wheel movement can load the clamp differently. A quick hand check after installation and before critical measurements can prevent false diagnosis.
Runout compensation can correct predictable mounting offset. It cannot correct a clamp that moves during the procedure.
Diagnostic reference
| Finding | Possible meaning | Next check |
|---|---|---|
| Values jump after steering | Clamp or target holder movement | Check locks and repeat compensation |
| One wheel fails repeatability test | Uneven jaw seating or unsuitable contact point | Reposition the clamp within its approved range |
| Wheel finish marked | Incorrect contact protection or excessive force | Use approved protectors and installation force |
Workshop procedure
- Confirm wheel diameter is within the clamp range.
- Inspect jaws, pins, protectors and threads.
- Choose clean, structurally suitable contact points.
- Tighten evenly and verify full engagement.
- Install and lock the target.
- Gently check for independent movement before compensation.
Frequently asked questions
Should every clamp be tightened as much as possible?
No. It should be secure using the approved method. Excessive force can damage the wheel or clamp without improving measurement.
Can compensation eliminate all clamp installation error?
It can correct repeatable eccentric mounting effects within the system design, but the clamp must remain stable.
Why inspect clamp threads and contact points?
Wear or contamination can change clamping force, seating and repeatability.
Technical reference · Published 17 July 2026 · Review product documentation before service.