Chuck, the old hand on the hub trick works well. What I did notice once I changed over to the infrared unit is that when one hub read 10 degrees above the other side I pulled and cleaned the whole hub and bearings. What I found is the inside race had some stain lines where each roller had set while there was apparently some moisture in the hub. Those stain lines would soon have turned in pits which over time would have destroyed the bearing causing it to fail. I find it very useful on a long haul.
PPG