Bearing Buddies

I wouldn't take them off my boat trailer, but I wouldn't put them on either.

What do they do? They keep positive pressure in your hub - to keep water out.

How do they do it? By using a spring loaded sealed grease chamber which you pressurize by pumping in grease, some of them even bleed off excess grease/pressure.

Why am I not a fan of such a marvel?

First, if the hub is full of grease, you don't need pressure to keep the water out...the grease will keep the water out.

Second, it's possible to have the correct pressure in the hub (the red line is visable) and yet have no grease on the bearing.

Third ,almost everyone who uses these devices carries a grease gun and tops off their bearing buddies,  or re-pressurizes them at regular intervals. Why is this necessary? I'll tell you why. Grease, unlike gasoline, isn't consumed - how often do you have to add grease to your car bearings? So if I pump grease in at regular intervals, where is it going? It's replacing space that should have been filled with grease to begin with, or it's pushing grease past the rear seal into the brakes. And it may even be pushing contaminated grease or water into the bearing as it moves the grease from the dust cap to the rear seal then out into the brakes.

Did you ever lose one? I sure have. Do you know what the driver behind you thinks when he sees that hunk of metal coming toward his windshield? And now you're without a Bearing Buddy and the innerds of your hub are exposed - Oh My! The world will come to an end...maybe I need to carry a spare (or two or three). The fact is, they call them a dust cap for a reason - to keep out dust...but a little dust isn't going to have any effect on a properly packed bearing - even when submerged, at least it's never been a problem for me.

Bearing Buddies do do some good though. They bring an awareness that mechanical parts are present and those parts do require a bit of maintainence for a long service life.

For you grease pumpers, there is a hub system that does what it's supposed to do. It's known by several different names (EZ Lube, Posi Lube, Spindle Lube)...what they do is direct that fresh grease behind the inner bearing, and as you pump, the new grease forces all the old grease out of the hub (at the dust cap). You not only repack your bearings (and completely fill the hub cavity) but can also examine the grease that comes out of the hub to see if it indicates pending bearing trouble.

I guess I might as well touch on oil bath hubs too - the kind the big rigs use. From my perspective, oil bath hubs are a solution to a problem that doesn't exist, not to mention they require special parts which are not convenient to obtain in an emergency. Fill the hub with grease when you pack the bearings and you're good to go for thousands of miles - which is what you'll be doing if one of your oil bath components fail on the road.