Skip to Main Content Skip to Footer Content

Agri Supply® is an exclusive supplier of the Bearing Buddy®

Why the Bearing Buddy® is needed.
For Boat Trailers - Trailering, even a short distance, heats the hubs. When the wheels are submerged during launching, the hubs suddenly cool and the air inside the unprotected hubs contracts, forming a vacuum which draws in water through the rear seals. There is no such thing as a rotating seal that stays perfect. Water and grit thus drawn into the hubs relentlessly destroy bearings. When properly installed and maintained, Bearing Buddy® prevents wheel bearing failure and eliminates bearing repacking. Boat trailer wheels can be completely submerged.
Utility Equipment, ATV, Horse, Camping, and other occasional use trailers - These trailers, because they are not used regularly, are also subject to bearing corrosion and failure from condensation moisture from air sucked into hot hubs as they cool. Moisture stays in the hubs causing rust and pitting until they are reheated when the trailer is used again.
BEARING BUDDY® VS. OIL BATH - Some trailer manufacturers are offering an oil bath system as an alternative to a standard bearing protector, such as Bearing Buddy®. They claim that since long haul trucks use this system it must be a superior system to a grease packed hub. What they fail to recognize is that America's highways are the perfect environment and application, as the constant miles and tire rotation keeps the bearings well lubricated. Boat trailers, however, operate in a completely different environment. The hubs on a trailer can heat up during long trips and when they are dipped into cool lake water, the sudden temperature change creates a vacuum inside the hub. This vacuum will draw any condensation, moisture, or impurities directly into the bearings, which can cause premature bearing failure. Standard bearing protectors, such as Bearing Buddy®, make it easy to visually check the amount of grease inside grease packed hubs. The internal spring piston exerts about 3 p.s.i. against the grease to ensure that no water enters the hub when the hub is submerged during loading and unloading. When properly maintained, there are no voids inside the hub where condensation can form during winter storage. By comparison, oil bath hubs should be checked after every loading/unloading cycle to make sure water has not penetrated and diluted the oil. Small leaks can cause the oil to escape and once this happens, bearing failure is quick and complete within a few miles. Most oil bath hubs are only half filled with oil and must be carefully inspected to maintain the proper level. Too much or too little oil could cause problems. If a Bearing Buddy® is knocked off, it would still be possible to run for many miles without bearing failure. This would not be possible with an oil bath. Bearing failure would occur within a few miles.

How Bearing Buddy® Works
The axle hub is filled with grease until the grease forces the Bearing Buddy® piston outward about 1/8 inch. Because the piston is spring loaded, the piston exerts a slight (3 psi) pressure against the grease, which maintains a slight pressure between the inside of the hub and the outside environment. When the hub is submerged, water cannot enter the hub because of this pressure. An automatic pressure relief feature prevents over-filling and over pressurization. Bearing Buddy diagram Without this feature, the inner seal will be damaged.
Grease can be added to the hub through an easily accessible grease fitting located in the center of the piston. Lubricant level (and pressure) can be checked quickly by pressing on the edge of the moveable piston. If you can rock or move the piston, the hub is properly filled. Bearing Buddy® will last the life of your trailer. The outer barrel is made of steel and is triple chrome plated. Internal Bearing Buddy® parts are made of stainless steel. Bearing Buddy® is also available with a stainless steel barrel for maximum corrosion protection.

Frequently Asked Questions
1. How can I tell if I have genuine Bearing Buddy® wheel bearing protectors on my trailer?
Genuine Bearing Buddy® units have an adhesive label on the Bearing Buddy® itself, with the words "Bearing Buddy®" printed on the label. If it doesn't say "Bearing Buddy®" on the label then it is a copy, and not a "genuine Bearing Buddy®."
2. What can cause a Bearing Buddy® to fall out of the hub?
The most common reason is the hub bore diameter is wrong, because the hub manufacturer did not maintain quality control during production. The spindle may be too long, which could cause the nut or cotter pin on the end of the spindle to push against the Bearing Buddy® piston (when grease level is low), eventually forcing it out of the hub. Excessive removal and reinstallation of a Bearing Buddy® can wear down the Bearing Buddy® shoulder (the part that fits into the hub), which decreases the interference fit between the Bearing Buddy® shoulder and the hub bore. An out-of-balance tire and/or incorrect bearing torque can cause excessive "wheel play" or wobbling, which can cause a Bearing Buddy® to work its way out of the hub. Installing the wrong size Bearing Buddy® for the hub bore diameter. Theft.
3. With Bearing Buddy® installed, how often do I need to repack my bearings?
We don't recommend inspecting your bearings more frequently than once every 5 years, provided you properly maintain the grease level in the hubs, and your bearings and seals are in new condition when you install genuine Bearing Buddy®. The Bearing Buddy® system maintains a constant pressure of 3 p.s.i. on the grease inside the hub. Since the hub is always full of grease (with proper maintenance) there is no need to repack your bearings. Some customers have reported that their Bearing Buddy® units were removed for the first time after 10 to 15 years of use, and the bearings still looked like new.
4. How do I determine the correct Bearing Buddy® model for my trailer?
Measure the inside diameter of the hub or the outside diameter of the dust cap shoulder (the part that fits into the hub) with a caliper or micrometer. The measurement needs to be in thousandths of inches. Most marine dealers, auto parts stores and service stations have a caliper or micrometer and will gladly measure your dust cap for you. You have two options to finding the right size for you:
1. You can use a "size gauge card" (see image below). These cards can be found at the Agri Supply® location near you.

2. You can use the "Selection Chart" below.