1. Reverse‑calculate limit from measured vibration and temperature rise curve.2. Vibration threshold: RMS velocity >2.5 mm/s indicates excessive preload or incorrect clearance.3. Temperature: use cooling slope after shut‑down to judge over/under‑lubrication.4. Contamination: introduce a<sub>ISO</sub> factor based on oil cleanliness.5. Mounting interference: heat inner ring; measured reduction in clearance should be within ±15% of calculated value.6. Material fatigue scatter 0.8-1.2 is typically normal.
