EZ Lube/Ultra Lube

NinerBikes wrote:
The EZ lubes on my 21 ft TT tandem axle are spring loaded cups that basically are a grease reservoir under pressure, pushing grease at all times towards the back side of the axles, and the seals there. You can watch the cup move outwards radially towards the grease gun as you pump them up, taking up the spare spring space. I fill mine with the grease gun every couple of years. I managed about 20,000 miles from when bought new to just this last April when I hit them for the first time with the grease gun.

How far do you drive on your car bearings without repacking them with grease? Same principle.

These are not EZ Lubes, they are Bearing Buddy's which are used a lot on boat trailers because the slight pressure keeps the grease packed which keeps air and water out which makes the bearings last longer and helps to prevent a bearing failure. The zerk fitting is not tapped into the axle as is the case with EZ Lubes, it is a part of the cap. Here is a link to the Dexter site which explains EZ Lube:

EZ Lube

Here is a description of Bearing Buddy found on Amazon:

Bearing Buddy Outer Bearings - Model 1980SS - Boxed Pair - When backed into the water for launching, boat trailer wheel hubs, heated by travel, are suddenly cooled. Air inside the hubs contracts and a vacuum is created. Water and dirt are sucked into the hubs through the inner seals and corrosion sets in immediately. Bearing failure can be expected within two seasons in fresh water - one season in salt water. When properly installed and maintained, bearing buddy prevents wheel bearing failure and eliminates bearing repacking. Boat trailer wheels can be completely submerged. Bearing buddy also prevents bearing failure on motorcycle, utility, snowmobile, camping, and other trailers by eliminating moisture build-up in hubs and providing proper lubrication. A wheel hub does not have bearing protection unless a slight positive pressure is maintained inside the hub. If pressure is not maintained, water will enter and corrode bearings. Bearing buddy creates this pressure, which is limited to 3 psi. features The original product proven in 25 years of service keeps water and dirt out of hubs makes boat trailer wheels safely submersible, ends the mess of repacking bearings. Pressure relief feature protects hub seals, prevents over filling, quick, positive lubricant level check. Made of steel and 100 percent inspected for long term tight hub fit quality construction. Heavy stainless steel barrel, stainless steel internal parts, clam shell packaging.

And a link:

Bearing Buddy