This is one area that always seem to create a great deal of confusion and opinions on everyone’s part. The choice of bearing lube has a huge impact on any bearing’s rolling properties. Thinner is better, no doubt. But it requires more attention and maintenance. Some use them and some do not. The trade off is always protection vs friction, but consider the following:
Seals do not keep dirt out and lube in. They just slow the process down.
Seals and shields seem to guarantee that bearings are seldom cleaned and re-lubed.
Metal shields make it virtually impossible to use anything other than a grease in them.
Running without either does not result in the dirt build up you might think, here’s why:
On the racetrack, the rotation of the balls results in an air current or “dam” that is more effective in keeping dirt out of the races than you may think. Sure there’s a great deal of build up on the exposed inner/outer races and ball separators, but take a look in the ball races. You may be pleasantly surprised. So before you contact us with your question, remember that there are snowmobile grass drag guys that run an entire season without them.
Some Cautions:
Wet environments complicate things.
Powerwashers are even worse.
Plastic caged bearings have one side more
exposed than the other (buy an axle mounted shield).
Tapered bearings cannot use the same thin lube that
ball and roller bearings can.
