Crank Bros. Opium SL directset review [o]
 

Didn't need a new headset, but came upon a steal of a deal on one, and though I'd check it out... Went into my burly hardtail frame/Lyric Solo Air fork combo. It looks a bit odd, since it's so tiny, yet gives a sleek, clean look at the same time, IMO. On frames with large headtubes it might look very out of place, though not a concern for myself.
http://i44.photobucket.com/albums/f1...8/IMG_0010.jpg
Weight: though the topcap/bolt/starnut setup is pretty standard and nothing special, the cup/beaing setup was ~35gms. less than my King/Cane Creek S-3 conglomeration it replaced. Lightest thing going other than some of the super light weight weenie offerings of dubious durability. As well, for a 1-1/8" non-internal/non-integrated headset, it's got the lowest stack height I'm aware of.

Install: super easy, even without a headset press. One padded up 32mm flat wrench, one hammer. Lotsa' grease on the cup skirts, and a nice cleaned inner headtube. Things slid right in with some gentle love taps from the hammer. No loose feeling, but not super tight either. Of course, that will vary depending on the specifics of your particuler frame. I have read a few anecdotes of people trashing theirs upon install, and can't for the life of me figure how they did it, unless they are just plain hamfisted mechanics. Caveat: use the supplied ring for the upper cup on install, use grease (per Crank Bros. suggestion) and do one cup at a time, not both.
http://i44.photobucket.com/albums/f1...8/IMG_0013.jpg
Sealing: seems decent, no better or worse than the King and CC offerings I've used. However, this isn't a no maintenance set, IMO. So long as you give the bearings a cleaning out, they should last a long time before needing any replacement, if ever. I didn't, but it appeared that removing the sealing to clean/lube/regrease the actual bearing setup should be fairly easy.

Durability: it's light. That said, the only real issue I see is if you happen to have a wreck that managed to bash the outers of the cups/bearings on a rock enough to dent things, which would likely screw the whole thing up. I've never done that to any headset in 15+ years of riding bikes though, so seems like a long shot. Flex? The thing is tiny, with a tiny little crown race. Methinks things could be ab it more flexy due to this, but OTOH you also don't have the potential for the bearings to slop around inside the cups, since the bearing outers are the cups. Maybe long term use for hucker types might not be a good idea just due to the size and overall lightness. I dunno. I think I'd be more inclined to want a slightly wider base on the crown race to spread loads a bit more, but what do I know, eh? The very tiny crown race may be interesting when/if removal is needed.
http://i44.photobucket.com/albums/f1...8/IMG_0015.jpg
The only thing I foresee as a possible issue: the preload setup is not a split bit as on CC headsets, but an o-ring/topcap setup as King headsets use. However, the o-ring sits below the topcap and is then forced down when one tightens to bolt/starnut setup. Seems a better setup than the King version, but still not quite as good as the split ring of the CC variety. Time will tell. I didn't realize it didn't use the split preload ring beforehand, otherwise I'd likely not have bought. Again, we'll see how it goes.

First ride on it today, ~ 15 miles of rooty, rocky, tight and twisty singletrack at Blue Mtn. in Peekskill, NY. Slow speed trialsy moves, some fast descending, a couple 2-3' drops and one int he near 5' range. No noise. No loosening. No untoward flexing. Other than visually, I couldn't tell a damn bit of difference on the front end over other good headsets I've used. Dropped a couple mm off my axle to headtube height, gaining a bit more steer tube up top (just added some spacer to the stack for now) and otherwise just felt like a nice smooth headset.