Bicycle Mechanics - Sealed bearings

I'm overhauling my touring bike's front hub, and I want to replace its #6200 sealed bearings. I know all #6200 bearings have the same dimensions, but are they the same on the inside as well? In other words, are all #6200 sealed bearings appropriate for use in bicycle hubs? If not, how do I know which ones are? Thanks.

Coincidentally, I am just going through this myself and have 6200 bearings on my rear hubs. Talking to a guy at an actual bearing supply house I was told that bearing designations are pretty much universal. A 6200 bearing is 9x30x10 mm, IDxODxW. Sometimes the dimensions are listed in different order, but it comes to the same thing.

One thing I don't understand about my bearings is that they are actually marked 6200NK. The bearing guy said that this is an identical bearing, but the NK means it is intended for use with a spring clip. I see no sign of a spring clip or any place one could be retained. I would love for someone to shed some light on this.
Thanks,
Raymond

Originally posted by RainmanP
Coincidentally, I am just going through this myself and have 6200 bearings on my rear hubs. Talking to a guy at an actual bearing supply house I was told that bearing designations are pretty much universal. A 6200 bearing is 9x30x10 mm, IDxODxW. Sometimes the dimensions are listed in different order, but it comes to the same thing.

One thing I don't understand about my bearings is that they are actually marked 6200NK. The bearing guy said that this is an identical bearing, but the NK means it is intended for use with a spring clip. I see no sign of a spring clip or any place one could be retained. I would love for someone to shed some light on this.
Thanks,
Raymond Maybe the spring clip is not necessary if another machinism is used to retain it.You may need the nk designation in either event.

I've looked around on the web for information. FWIW, all the specs I checked for a 6200 sealed bearing had 8 caged bearings and identical load ratings. There didn't seem to be any consistency in the type of lubrication used, in fact, many bearing manufacturers would use whatever lube the customer specified... but I doubt any producer would be too responsive to an order from me for two with Phil Wood grease.

The additional designation after the 6200 refers to the type of cover(s) on the bearing. A plain jane 6200 has both sides open. Shielded bearings have a metallic cover crimped into place on one (6200 Z) or both sides (6200 ZZ). Sealed bearings are, well, sealed on one or both sides. I found two different designations for sealed bearings, RS and RU. I don't know the difference (anyone know?). Anyway, a 6200 2RS has seals on both sides, while a 6200 RU has a seal on only one side. I didn't see any marked as NK.

The bearings I removed from my front hub were marked as 6200 RU, but since they had both sides sealed, I'm assuming they were 6200 2RU. One of the internet bike supply houses sells only Enduro 6xxx 2RS bearings (http://www.biketoolsetc.com/). My lbs sold me a couple of those same bearings as replacements. They fit perfectly... and all seems well.