New wheel bearings

[bwringer]

The only reason there's only one seal on some OEM bearings is that it saved Suzuki something like 0.2 yen per bike.

Again, remember that these bearings are standard industrial bearings engineered for much, much higher loads, speeds, and temperatures than they ever see on a motorcycle.

Only two things kill motorcycle wheel bearings: installation errors and contamination. I've never seen one wear out, but I've seen lots that were damaged when the bearing or the wheel was installed (most often leaving out spacers).

I've also seen lots of wheel bearings that were damaged by water entry. For example, if you rescue a GS, you'll often find that the right side front wheel bearing has water in it from sitting on the kickstand in the rain. Quite often there's water and corrosion in the wheel hub and the left bearing as well.

[Grimly]

I've also seen lots of wheel bearings that were damaged by water entry. For example, if you rescue a GS, you'll often find that the right side front wheel bearing has water in it from sitting on the kickstand in the rain. Quite often there's water and corrosion in the wheel hub and the left bearing as well.

Agreed with all of that, and especially the last point. The ones I had that failed early were the single-sealed OEMs and they had signs of water ingress, likely from what you describe, but also, once the seal goes the bikes that are used for year-round general commuting purposes in the UK have a short bearing lifespan left, as the road salt gets in and wreaks havoc.

Not every bearing maker is the same - I had stuck with Koyo long before I worked for a bearing maker. One of our customers was Koyo. We had to bust a gut to meet their stringent requirements and tolerances.
That impressed the crap outa me, I can tell you. I already knew they were good - it was then that I realised how good.
We also made balls for various other brands - you would be surprised just how slack and cheap was acceptable enough for some of them.