You’re running down the highway at 65-mph. It’s zero-dark-early in the morning, as you head for the boat ramp and a full day of fishing--but suddenly there’s a strange vibration in the steering wheel. Then the grinding sound of metal on metal drowns out the pre-fishing tunes on your truck radio. You move your foot from the gas pedal to the brake, glance in the sideview mirror, and see a cloud of smoke so thick you’d think you were in Baghdad. Pull over, quick! Your wheel’s about to fall off, because you just blew out a trailer bearing.
Have you ever lived this trailer-boating nightmare? Probably–most of us have experienced this one time or another, and dedicated trailer boaters pay a lot of attention to their bearings’ condition and regular maintenance. While we’re all used to dealing with grease bearings, a new option for the trailering boater is oil-filled bearings.
Naturally, the manufacturers of each product says theirs is best. The oil-filled hub manufacturers make some big claims, and the grease guys spend their time shooting them down while reminding us that it’s foolhardy to fix something that isn’t broken. Although grease bearings are generally considered reliable and inexpensive, oil-filled bearings may in fact be significantly better: their manufacturers claim you can trailer up to 40,000 miles without changing the lube (3,000 to 4,000 miles is generally considered the norm for grease bearings), they reduce bearing wear and friction (which contributes to a gain in tow vehicle efficiency,) and they are easily monitored via a see-through cap on the hub. Of course, there are some down-sides to oil-filled rigs, too: this type of bearing may allow condensation to form in the hub, ultimately leading to bearing failure, they are more expensive than conventional bearings, and they won’t work with solid rotor disk breaks. If that’s what you have on your rig, the whole argument is a non-issue.
So, which bearing system is superior? Let’s look at the arguments one by one. First off, ease of maintenance. Yes, oil baths can be expected to go much longer distances than grease, but only if they are used on a regular basis. Let them sit for a few weeks and condensation can form in the hub. Then pitting takes place on the bearings, and the next break-down is just a few miles away. This problem can be solved by rotating the tires every week or two that your trailer is laid up. Oh joy, as is you didn’t already have enough to do. So you’ll find oil advantageous if you trailer long distances with regularity, but grease wins out if you trailer only on occasion, or if you don’t use your boat for weeks at a time during certain periods of the year.
Next, consider efficiency. Talk is cheap and no one offers cold hard numbers on the subject. So far, we’ve simply been told that they have less friction and more lubrication, which means better efficiency. But there’s only one crowd who’s telling us this. Yup, you guessed it—the oil hub manufacturers are the folks making the claim. Are you going to take the manufacturer’s word for it, without any data to back it up? Fine, but I’m not—so I lay this claim aside until someone proves it to me. On to the see-through hubs and easy monitoring: If you like to know if your bearings are in good shape at a mere glance, then grease takes a bath and oil bearings are a big winner. But plastic shatters on impact, so if you tend to clip curbs while pulling around tight turns, you may want the old reliable grease hubs on your trailer. Expense? Yeah, oil baths are more expensive—by five or ten bucks. That’s peanuts in the scheme of things, and cost is a non-issue that the grease guys bring up only because they’re short on ammunition. In a way, the grease supporters shoot themselves in the foot with this argument; in the long run oil filled bearings may actually save you some cash because their longevity means you won’t have to change the bearings out nearly as often. Wait a sec, there’s more. If you’re like me, you’ve probably changed out grease bearings time and time again. You’re used to the job, and won’t hesitate to do it yourself. But oil filled bearings are a different matter. Few of us know how to deal with them, which means you’ll have to pay a pro to install them and work on them. This could tip the financial argument back in favor of the grease variety. Considering how many “ifs” there are in this argument, I call it a wash. In the long run, either one could turn out to be more or less expensive.
There are a few other factors to consider, too. Remember that grease bearings are the norm across the country, and parts can be found for them anywhere, any time, with ease. Not so with the oil filled variety. Experience a failure in an area where there aren’t any near-by dealers, and your rig could be sitting on the side of the road for a while. Grease bearings, on the other hand, will often keep on spinning long after a problem arises, allowing you to make way for a repair shop instead of leaving you on the shoulder. Oil filled bearings usually go in a more catastrophic manner—everything’s running just fine, then a failure suddenly forces you to the shoulder. Of course, both of these issues are pretty easy to put to bed: simply carry a spare at all times, and know how to swap it out.
Now can we answer the original question: which system is superior? As is true with boats, women and trucks, there are trade-offs involved with each choice. If you trailer on a professional level—long distances, on a regular basis—oil bath bearings are probably going to be the best option. That explains why many manufacturers of high-end tournament fishing boats, such as Ranger and Triton, have started packaging their boats with oil-equipped trailers. But if your personal trailering schedule is more erratic and your boat doesn’t move for weeks at a time, you’ll most likely want grease in your hubs. Will the manufacturers of oil-bath bearings agree? Nope. How about the grease makers? Uh-uh. But we think that after considering all the facts, those of us that don’t have a horse in this race will reach the same conclusion.
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| Hot grease bearings + cold water = big trouble. |
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