That Popular Mechanics advice seems a little light on bearing adjustment advice. A bearing site will generally give you a lot better advice on correct adjustment of taper roller bearings.
Adjusting taper roller bearings properly is a pretty critical process. With taper roller bearings that operate under really heavy loads, you need to have some preload on the bearings.
This means tightening the nut until there is some "crush" on the bearings. On the likes of dozers, taper roller bearings often have very high preload.
This amount of preload is often measured by a string scale attached to the gear or wheel, with a set amount of string pull in pounds or kgs.
If taper roller bearings have any amount of looseness in them, the races and rollers hammer on each other, and bearing life is reduced.
With wheel bearings, you need to set the preload at a point where there is no movement in the bearing, but not enough preload to create binding and heavy resistance to turning.
The technique I use, is to tighten the adjusting nut fully, with the wheel turning, until the wheel bearings start to bind. When installing new bearings, it's important to do this, as it ensures the new races are fully seated in their bores.
Once the nut is done up tight, you then slacken off the nut until it aligns to the nearest cotter pin hole, and then recheck to see if the wheel turns freely.
If the wheel is still binding, or feels a little tight to turn, slacken off the nut to the next cotter pin hole.
Under no circumstances should you have any movement (looseness) in the bearings .. measured by grabbing the wheel, top and bottom, and rocking it back and forth vertically.
If there's any "clunking" when you rock the wheel, you need to tighten the adjusting nut until the clunking disappears. However, always ensure that the wheel turns freely after you've road-tested the vehicle after adjustment.
Even a small amount of binding or drag from wheel bearings can increase fuel consumption. However, poorly lubricated or loose wheel bearings are just as bad as tight bearings.
Not many people regularly check wheelbearings for adjustment or the proper amount of grease .. or even worse .. rust, caused by water ingress into bearings, usually by driving through deep water.
You only have to see the number of trailers parked by the roadside with a wheel and hub missing, and a damaged axle, to figure that wheel bearings are the most neglected part of road-going equipment.
