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