Yesterday I was goofing around with Sheldon Brown's Internal Gear Calculator when I noticed a new option available - the SRAM i-Motion 9-speed hub. I did some searching, and there isn't too much info out on the web about this hub just yet, but I did find some interesting things.
1. A link to a PDF of specs for new SRAM technology on their website here: http://www.sram.com/en/service/sram/tech_specs.php
2. An article discussing it here (scroll to the bottom of the page): http://bicycletech.blogspot.com/
3. An MTBR thread discussing internal drivetrains in general here: http://forums.mtbr.com/showthread.php?p=1786335
4. And today, the official i-Motion website here (can anyone that speaks German give us the gist of what they're saying in the movie?): http://sram-imotion.com/
I'm not going to say much about the hub itself - I don't know much about the actual industry, so I'm in zero position to speculate about anything specific other than explicitely released information about specs, but given the specs on paper and SRAM's (both home-grown and inherited from Sachs) generally rock-solid reputation for quality components, this looks like it could be a real winner of a hub.
In my opinion, it looks like the future is bright for internal gear systems, and the next-generation hub market is really beginning to swell. It looks, to my layman, somewhat biased eyes, that derailer systems are beginning to (if they have not already) reach their practical limits for further development. There just aren't too many more cogs that we can cram onto a hub without seriously compromising wheel strength or durability. Increasing hub spacing to compensate could start producing chainline and biomechanical problems. Furthermore, adding all those cogs hasn't improved the number of useful gear combinations by a whole lot.
On the other hand, the development future for internal gear hubs looks like it might be wide open, especially in mountain biking, where rapid, easy gear shifts, strength and durability are important concerns, and in commuting and utility cycling, where low maintenance requirements and all-weather durability and performance are important. In fact, I think that the concept has long-since been proved (by Sturmey-Archer, in the first half of the 20th century) in the case of utility cycling, but the new hubs are beginning to make internal gearing more appealing for utility riders in hilly cities and for more performance-oriented, enthusiast commuters and utility cyclists. In case of mountain biking, hubs like the i-Motion 9 are beginning to reach the necessary range of gears for cross-country riding, without the chainline issues, shifting challenges and huge number of overlapping, useless gears in a 27-speed MTB drivetrain. I know that the Rohloff is already there, but the Rohloff remains a bit of a boutique product. In order to compete with derailers, the price of quality, wide-range internal gearing must come down.
Unfortunately, I really don't know what the mechanical and financial constraints on further development of relatively inexpensive wide-range internal gear hubs are. I don't know if there isn't much more than can be done, or if we're seeing something like the kind of rapid technological innovation that the derailer went through some 25 years ago, with the new Shimano and SRAM hubs being somewhat analogous to SunTour's slant parellogram - a major change, followed by a long series of refinements to the technology. I'm hoping that some of the more industry and tech-savvy BF members might be able to shed some light on this.
In any case, while it looks to me like we'll be seeing a lot more internal gear hubs in the future, both for utility and high-end use, I don't think it's very likely that the derailer will be entirely supplanted. After all, derailer gears are cheap, making them an appealing option for a wide range of gears at low cost. The only current hub that provides enough range for touring is the Rohloff, and as I said, I don't know how practical 14-and-higher-speed hubs will ever become, in terms of cost. I'm optimistic, but open to the possibility that they'll remain expensive, luxury items for the forseeable future. I also don't know if we'll ever see internal gears on fancy-pants racing bikes. This is due to weight (though the difference is less than it is generally made out to be), mechanical inefficiency (also not as bad as supposed, especially with the new hubs - I predict improvements here, too) and gear spacing that is too wide for maintaining optimum cadence at all time (a legitimate complaint against hubs, if you're a racer).
Anyway, that's my long-winded, very-very-non-expert take on the new SRAM hub, and on the future of internal gears. So... what do you think?