Question on inner bearing grease seals

Don't use the EZ lube feature and you won't have to worry about blown seals. There is also no need for EZ lube on a trailer that is never immersed in water like a boat trailer.

National seals all the way for me . . .

Are you really willing to risk your boat trailer for a few dollars?

Take the National part number and look it up on Amazon and Rock Auto. You will be surprised at the price.

I'll echo the same sentiment for quality seals and bearings.
Although I'll admit, a "quality" oil bath hub seal lasted about 500 miles on our boat trailer and I stuffed a $5 Autozone seal in it (in the parking lot, stupid oil hubs, grease could've waited until getting home or next year.....) and that was 2 years and a couple thousand miles ago.
I'd still buy better quality given the choice.

I worked in industrial maintenance at one of the largest meat slaughter and packing facilities for 10 years. National and Chicago Rawhide seals are what was used in those extreme environments. From 100 below 0 degree blast freezers to 120 degree and up kill floors. I would stick with National or CR instead of no name brands. If you are worried about cash, try the cheapies. Maybe they will hold up? I'll pass. If you're broke down in the middle of nowhere, use what you can get!

Agreed on the quality for a trailer that is going to dunk the warm bearings under water.

If your trailer has the bearing buddy caps then the more expensive seals are hopefully double lip seals which are required. The cheaper seal might be only a single lip seal which will leak with the bearing buddy system.

National is a name brand and a manufacturer for others. I'd pay the $12 for that quality anyday.

Yes the better seals are worth it. As mentioned before they are better able to handle the pressure and vacuum that develops in the hub cavity due to heat cooling cycles. Really, it it worth $ 36.00 to have one of those $3.00 seals fail while on the road?

Some seals are designed to be used with the EZ lube or in the case of marine stuff "Bearing buddys" style grease system and are built to take the pressure (in theory..) created during the greasing process. Those seals cost more.
If you don't use that "feature" then the cheaper, more common seals work fine for RV's but for a boat trailer, I'd get the better ones becasue they have a tighter seal.

Scott