Originally Posted by interested
Doesn't have one myself, since I dislike riding bicycles with internal gears, this hub is however fairly common where I live, so I do have some knowledge about it. (I assume you don't mean Shimanos new so called "Ultegra level" hub.)
The verdict pretty much is, that this hub is OK for very light, low speed commuting, but are really bad for even moderate distance, all weather commuting (rain and frost).
A colleague of mine has a 25 mile round-trip commute. His 8 speed Shimano Nexus Rollerbrake broke 3 times within the first year, requiring a major overhaul each time, before it finally disintegrated two weeks ago. His new LBS (who sold him a new wheel) told him that he had to bring the hub in every 1400-1800 miles for preventive maintenance or it too would be destroyed.
One could probably do the overhaul oneself (inspection, grease repacking, perhaps changing bearings). But since people usually buy these hubs because the don't want to do maintenance work, they probably won't.
Anyway, if one does all-weather medium distance one one of these hubs, they should expect them to be much more maintenance intensive than a normal dérailleur.
People on the danish bicycle forums I hang out in, tells similar stories. The hub isn't watertight, meaning that road grit and salt and water penetrates it, destroying the bearings. One guy even claimed that the entire hub locked up when cold because of water inside it.
Another common problem is cable problems; since the hub has a weak internal spring (compared to dérailleur), the cable has a tendency to stick when freezing. Especially going from thaw to frost causes problems. Road grit or cable rust also hampers its cable action more than normal dérailleurs.
You can't use a QR with these hubs, so you need to ride with a wrench if you want to change the tube. The Rollerbrake version is really, really nasty regarding this, since all the bolts, nuts and cable adjustments, turns a simple tube-changing job into a laborious affair. (besides its breaking power doesn't impress me at all)
People also claim that the gear ratios aren't that good if you like to go fast (the SRAM 7 speed should be better in this regard). But I guess this is also a matter of personal taste.
Besides that, these hubs are heavy. I am not a weight weenie, but a rear wheel with such a hub, really feels like a bag of bricks to hold. The drag may be low, but for me it just sucks the joy out of cycling. This of course is a matter of personal taste, thousands of people use Nexus 8 speed hub and are very happy about it. The same with grip-shift; some like it, others don't.
The hubs are expensive. I don't know US prices, but where I live, a Nexus 8 speed rear wheel alone, usually cost the same as a pair of super strong Campagnolo Vento wheels + cassette, or a pair of Shimano wheels + cassette. Even a hand built rear wheel with Mavic rim and Shimano Ultegra hub are cheaper.
Normal dérailleurs are very simple, extremely durable and very low maintenance (if you don't mind that they look dirty), even though they look complicated with all their springs and moving parts. They are cheap too compared to internal gears.
In fact I personally can't find any significant point where these expensive (though not high quality) hubs with internal gearing are better than normal dérailleurs and hubs. Their perceived low maintenance probably is much worse than normal gears, they have drag, they are heavy, they are expensive, they make the wheel difficult to service, you are restricted to grip-shift (IMHO), can't run very fast because of gear ratios, may need more cable maintenance than normal etc.
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Regards
Peter H.S.