Trailer wheel bearing sizes?

[Noahsark]

1) How can you figure out what size replacement bearings you need, without taking out the bearings already on a trailer and not knowing the make or model of the trailer?

2) How often should bearings be repacked?

I would like to purchase an “emergency backup” set of bearings just in case I ever break down. I have never replaced or repacked the bearings on my trailer that I have had for 15 years. The only maintenance that I do is put a few squirts from the grease gun to the bearing buddies once a year. I trailer my boat often, but rarely very far, so I don't run with it at highway speeds other than a handful of times a year. I always feel the hubs for heat on highway trips and have never had a problem. I just figured that after 15 years, I may be pushing my luck.

Thanks in advance.

[Greg T]

You would probably have to remove an outer bearing and take it in to match up a new set. I repack my sled/utility trailer bearings each year after a certain incident that involved an 50 mile tow bill. I don't run the bearing buddy though, so that might make a difference.

[jweitgen]

You'll probably have to pull the bearings out. I tried to guess and was wrong. The inner and outer bearing may not be the same size.

[lawdog]

as jweitgen stated, there are some trailers that have a tapered axle and so the outer and inner bearings aren't the same. pretty standard trailer sizes are either 1" each or 1 1/16" each for straight axles and then either 3/4" by 1 1/4" or 1 1/4' by 1 3/8" for tapereds from my experience... I just redid on of our boat trailers and it has tapered axles the other of the same brand that we also have, has straight axles, so you really need to know exactly what's in there as just knowning the approximate size and brand won't necessarily be a sure way to know...

Good luck.

[deepportage01]

Just bring in the whole hub to northern tool and they will set you up rite. I would recomend buying 2 spare complete hub units they come pre greesed so is one go's bad on the road you don't have to pound bearings out of the hub on the side of the road ya just slap the whole new hub on and your back on your way. I pack my bearings once every year. I can't take credit for this advice LH2 told me this a couple of weeks ago it's a good idea!