Tip of the week...

[MotherNature]

Checking and maintaining the wheel bearings on your trailer is essential to optimum performance.

You should check your hubs at least twice a year and more if you travel to fish. If you are not mechanically inclined ask your local tire shop to take a look and if they don't handle trailers they will be able to give you a recommendation to someone who does.

[hesjustbassin]

That is very true (I learned this one the hard way), unless you get the maintence free oil bath hubs and bearings.

[Basscat7]

Most wheel bearing failures are from owners overgreasing and breaking the integrity of the rear bearing seal allowing road grime to enter the bearing and scoring the ball bearings themselves or the spindle.

When a bearing is hand packed with grease, and assembled correctly, and the seals are tight, there is no reason at all to be pumping grease into the bearing more than once a year, if that.  Especially if you have any sort of bearing buddies on the hubs.
A lot of guys follow the old wives tale of using a grease gun every trip or every other trip and pump a few shots of grease into a hub.  Reality is , you are doing more harm than good....if you started with good seals, after you finish pumping more grease in, you will do nothing but blow out the seals.

Grease in a trailer bearing does not dissolve, does not evaporate, it goes nowhere....except when you decide to do some good and get out the grease gun.... (wrong ).......if the bearing is full of grease ( and it should be if packed properly )  the only place for the new grease to go is to take the path of least resistance, which is the rear seal.   New grease in, old  ( still perfectly good ) grease blows out the rear seal.  Once this happens the first time, then you are committed to a cycle of losing grease thru the rear seal and pumping more in, not only that, you have now compromised the integrity of the bearing by allowing water/silt/sand to enter the bearing thru the blown seal, cutting the bearing lifespan considerably.  Most people have no clue that they have blown out the rear seal, they just think the hubs use a lot of grease.
First couple of boats I made the mistake of greasing and blowing out the rear seals like a lot of guys.
When I bought my last Bass Cat they told me the
new bearings/seals should be good for a minimum of 2 years before grease should be added.

  I was a little hesitant when they told me this, but after listening to their reasoning it made sense and I gave it a try ( still kept the grease gun in the truck, just in case LOL. )
I tow at least once a week on a 125 mile trip on interstates and a couple of 500 milers in summer. I launch in brackish tidal water . I am going on over 3 years with my Bass Cat trailer without touching the bearings or adding any grease.  I will repack them this spring.

Bass Cat has designed the newer trailer wheels so you need to remove the entire wheel to get to the grease fitting on the bearing buddy.  They did this by design after studying bearing failures and coming to the conclusion stated above.
People will be less apt to give a bearing a shot of grease if they have to jack up the boat and remove a wheel.
You put a lot more miles on your cars wheel bearings, but you don't grease them like you would your boat trailers......think about it.

[Mike Cork]

You put a lot more miles on your cars wheel bearings, but you don't grease them like you would your boat trailers......think about it.

I do agree that most folks over grease their bearings, however compairing them to a cars bearing is like apples and oranges unless you completely submerge your car in water twice a week, run it at operating temperatures and then dunk them in 60-70 water instantly. Boat trailer bearings endure much more sever conditions that a cars bearing ever will.

If you keep an eye on them, watch for grease splatters indicating a blow seal. No matter what kind of bearing system you have (other than oil hubs) I would highly recommend that you repack them annually and visually inspect them at least bi-annually. Grease breaks down, especially under the sever conditions that a boat trailer puts them threw. If you repack annually, unless a seal just blows for what ever reason, you shouldn't have to grease your bearings 

[Basscat7]

I do agree that most folks over grease their bearings, however compairing them to a cars bearing is like apples and oranges unless you completely submerge your car in water twice a week, run it at operating temperatures and then dunk them in 60-70 water instantly. Boat trailer bearings endure much more sever conditions that a cars bearing ever will.

If you keep an eye on them, watch for grease splatters indicating a blow seal. No matter what kind of bearing system you have (other than oil hubs) I would highly recommend that you repack them annually and visually inspect them at least bi-annually. Grease breaks down, especially under the sever conditions that a boat trailer puts them threw. If you repack annually, unless a seal just blows for what ever reason, you shouldn't have to grease your bearings 

Mike
If the bearings are packed correctly and the seals are new and installed right there should not be any reason for operating temps to have any effect on the bearings being dunked in water.
There is not enough temp difference to even begin to break down the grease, unless the bearing or seal is already defective and the wheel is red hot.
I agree they should be monitored every trip and the temp of the wheel should be barely warm to the touch.
If the grease in the bearing is not contaminated by a seal being defective it should not break down for a number of years. Newer greases do not break down like they did in years past.
I have had a number of guys do away with the grease guns and all have gone at least 2 years without a repack. I have over 3 years on my tandem axle Bass cat and have not touched, greased or repacked the bearings.  I will this spring, but the wheels are still not getting hot tot the touch.
Nothing wrong with repacking once a year if it makes you feel better, just that it is not a necessity if the seal job is done correctly the first time.