How Trailer Wheel Hubs Work

By: Cristen Conger

Trailer Wheel Hub Kits

Trailer wheel hub assemblies can come pre-assembled or pre-greased in kits.
Trailer wheel hub assemblies can come pre-assembled or pre-greased in kits.
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Instead of having to purchase the many parts of a trailer wheel hub individually, manufacturers offer them as kits. Many such kits come with bearings, seals, a grease cap, a cotter key and nuts and bolts. Some offer the option of having the bearings preassembled and already greased as well.

Just because a hub assembly comes pre-greased, that doesn't mean it's greased for life. You should still check it regularly for corrosion, cracking or other damage at least once a year. Bearing Buddies can make that maintenance process simpler. A Bearing Buddy is essentially the same thing as a grease cap, except that it has an opening for a grease gun that allows you to inject new grease into the bearings without having to pack it by hand. Unless you have a wheel hub assembly with this type of cap and a system for expelling the old grease without removing the bearing from the hub, you must still take the hub off the axle and clean it out.


If you're in the market for a trailer wheel hub assembly kit, you'll also need the same information mentioned on the previous page to know the right one to buy for the size of your trailer wheels. Whole kits aren't necessary to install your trailer wheel hub, especially if you just have a problematic bearing or grease seal, which are the most commonly replaced parts in the hub assembly. You can buy those parts, or any other in the trailer wheel hub assembly, separately.

Now that you have your wheel hubs locked and loaded and tires securely in place, it's time to tow. Roll on to the next page for more information on towing and auto topics.

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More Great Links


  • "Bearing Service." The RVers' Corner. (Oct. 16, 2008)
  • "Replacing the Bearings, Races and Seals on a Trailer Hub." e-trailer. (Oct. 16, 2008)
  • Siuru, William D. "Keeping Trailer Wheel Bearings Going Round and Round." New Car Buying Guide. (Oct. 16, 2008)
  • "SuperLube Wheel Hub/Spindles Owners Manual." Tie Down Engineering. 2004. (Oct. 16, 2008)
  • "Wheel Hubs: Technical Information." Eastern Marine. (Oct. 16, 2008)