<raises hand> My original Surly hub bearings crapped out on me in the same way, too! Through that, I learned to recognize the signs of a dying set of bearings. I exercised this recognition 8 months later on the next pair of bearings.

I now have a Dura Ace rear hub (loose ball) and overhaul every 3 - 6 months, depending on how lazy I am. I grew tired of buying new bearings every 8 months. Of which the last 2-ish months I have to contend with a rough spinning wheel. I now save the old Surly wheel for salty winter roads. Which after 2 winters is due for a new set of bearings...

I bought a cheap Formula hub - Sun M13 rear wheel. Other than that I have wheels with loose ball bearings

I just run whatever comes in the hub, or whatever the industrial bearing supply company in town has. You can also order bearings from McMaster. They're all designed for orders of magnitude more force and RPM, and it's not like you need ABEC 5 bearings so it should be fine.

Hey thanks everyone, that's awesome. I've learnt a lot. Really appreciate it.

hey, er, butthole_surfer that's an interesting angle too, cheers.

McMaster doesn't carry the bearings for the Surly Hub. There's one maker and seemingly a few retailers for these particular bearings. Odd size I suppose

Interesting. I'm not sure why this did this... I dig my Formula hubs because I no longer have to mess with adjusting cone nuts and they spin nice and smooth right out of the box.

Sealed bearings generally don't need to be maintained as much as loose bearing.
If you like doing repairs and maintenance then loose ball is just fine.

I know people that have ridden on sealed hubs for years and they are still just fine.

I'm riding on sealed hubs right now and I love the reliability of it. My old wheels were laced to loose ball formula hubs and they required a lot of adjustment to the cones to keep them running well.

I dislike this design as is is proprietary... get a Formula hub, one of it's clones, or a better PW or Arvon hub and the cartridge bearings are standard, rather inexpensive, and very easy to service when they actually need it.

If you adjust your cup and cone bearings properly they should stay in adjustment and service should be based on mileage and conditions... some have better seals than others and I am rather partial to vintage hubs that have an oil port and can be lubricated in this manner.

You need to do it more frequently but the fresh oil flushes out any contaminants and they spin so smoothly.

IRO is still selling hubs for $20 each.

I have no idea what 6901RS means, but i bagged a couple real cheap from teh lbs.

a quick search turned this up:

http://www.vxb.com/page/bearings/PROD/12mm/Kit7489_1

seems like they'll fit my surly hub with a whack or two...

look up the DIY thread on here, you'll see how to nicely install bearings for next to nothing