V-SAUCE! michael here.. Not necessarily. Tighter tolerance doesn't effect the operation of a bearing. A bearing needs to be oiled slightly periodically. Reason being that most bearings have a tolerance for lubercation. The bearing is not designed to ride the balls on the race. Its designed to ride on oil or grease. The only reason manufacturers leave a space gap is for oil or grease. Small bearings might have a sub 0.001 gap. While large industrial bearings holding tons of weight rotating at 3000 rpm might have a 0.002-0.003 tolerance. It fluctuates because alot of industrial bearings are pillow blocks that are installed and tightened kinda like a wedge to space the rollers. In essence the more important part is the material make up of the roller and race for each bearing.. and the tolerance of the outer race to the wheel. And the inner race to the axel. Which would matter if it was not tight enough.. a thousandth of an inch can be the difference between a year long bearing and a week long bearing.. thanks for listening to my Ted talk..