Bending moment is the force exerted by the tire and wheel when in a turn. Standard bearing races are about 2 inches apart. As the distance between the races increases the bending moment decreases. this is good. The never lube races are 1/8 inch apart. This is bad. the bending moment must be extreme. That is why they can't stand an offset wheel. That is why they fail. What junk. I lube my standard brgs every 25,000 miles. Lube the front brgs on my 3/4 ton every brake change, 70,000 miles. Lubing every year is BS.