Originally Posted by
Spasticteapot
One online group swears up and down by the Shimano series of internally geared hubs, with many members reporting failures in their SRAM products. A local mechanic, on the other hand, reports problems with badly designed seals and water leaks on the Shimano hubs.
Does anyone here have any comments or recommendations on these?
The first many versions of the the Nexus 8 speed really had horrible sealing that lead to heavy pitting of the cups and since one of the cups are part of the hub shell that isn't sold as a spare part, this meant a entirely new hub. Since IGH's are popular in my country, that meant that bike shops daily had people coming in with destroyed hubs. The majority of danish bicycle industry simply started boycotting the Nexus 8 speed because of the massive problem around 2006/2007, and
AFAIK, still do. According to the service manual Shimano has yet again tried to improve the sealing, so perhaps the problems aren't so bad anymore if you get the newest version of the Nexus 8 hub.
A lot of people think that IGH's are zero or low maintenance. They are not, they just change the maintenance pattern somewhat. But inside every IGH there is a normal hub, and that hub needs caring for; if it is cup-and-cone, you need to regrease and inspect at intervals according to your riding style, just like any other hub. You also need to make sure that the cone system isn't overly tight. If you don't do that you risk pitting the cups and that will often mean a new hub or wheel. Pitted cups are one of the most likely failure modes of IGH's I know of.
The internal gear system is quite low maintenance, but it still needs overhauling at certain intervals. I think Shimano says every 5000 km or every two years, whatever comes first. But if you ride fast in bad weather, like rain, or with winter salted sludge on the road, that interval may be much lower.
Here is pdf that shows the minimum overhaul (greasing) of hub and gears (German only, sorry, but the pictures really says it all:
http://www.paul-lange.de/produkte/sh...lung_Nexus.pdf
The Sram Spectro 7 speed has the best reputation for durability and weather resistance where I live (3 speed IGH's are probably among the toughest IGH's around, but has too few gears for many people), but even the Sram IGH needs maintenance.
Grease lubricated IGH's like Shimanos also tend to gum up and freeze when it is too cold. Quality sealed cable systems also reduce the risk of ice in the cables hampering gear shifting (the return spring are weak in most IGH's).
Shifters should also be part of your consideration of which IGH to buy. If you hate grip-shifters, don't get a IGH that only offer that shifting mechanism.
--
Regards