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  1. #1
    Senior Member grolby's Avatar
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    Thoughts on the upcoming SRAM 9-speed hub (and the future of internal gears)?

    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?

  2. #2
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    The only experience I have actually riding internal gear hubs was on a Japanese 3sp from the 1960 era. First gear was very sluggish and if the temp was below 5C, you were in real trouble. I have many miles on deraileur systems with no really bad experiences to report. I like the broad and easily modified gear range and the ability to provide wider jumps between lower gears and narrower jumps between higher gears. I do not find them to be high maintenance or finicky. The thing is that I have done some touring in situations where IF I had sucked a branch in a rear der. I might have faced hypothermia or worse. I also commute and have a marked disinclination to maintain that bike (or ever even wash it). Sooo I am certainly open to internal gearing. I would love a reasonably priced system with sensibly spaced gears....I think that to drive tech. dev. we need many more riders with a higher degree of technical expectation than the typical entry level cyclist. There is no doubt that this can happen...the profit margins must exist for this to become reality.

  3. #3
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    Good thoughtful essay.

    The drawbacks to internal gear hubs are greater weight and lower efficiency which will probably not be solved soon, if ever, and that will keep them from replacing derailleur gearing systems for performance riders. They certainly are making inroads in the utility market and are excellent tools for that use.

    I wasn't aware of the new SRAM 9-speed unit but, as you noted, Sachs was in the market in a big way in the past. Shimano has both 4 and 7-speed internal gear hubs and, of course, Rohloff has the very high end of the market to itself at present.

    It will be interesting to see how this all develops.

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    I'll consider buying one, but looking at the specifications I'm a little disappointed by the gear range of only 340%.

    The gear spacing is a little closer than on my S7, but I've toured fully loaded with it and the gear steps weren't a problem - the problem is that I need to match the sprocket I use to the terrain I'll be cycling so if I'm going somewhere very hilly my top gear only allows me to pedal on the flat at about about 32km/h, or if its mostly flat I don't have a low gear for hills.

    I'd have been more likely to buy the i-9 if it had a bigger range - not sure its different enough from my S7 to justify. I don't think its quite there yet - 11 or 12 gear with a range >400% and it could be competing with the Rohloff. I'm sure there'll be another hub from SRAM in a couple of years time that'll be closer to the Rohloff, so probably I'll just wait until then.

    There was a thread a little while back where some guy was trying to convince everyone that hub gears are just a marketing ploy and that they don't offer anything over derailleur systems. I absolutely disagree with that. If Rohloff hub gears were half the price they are I'm sure the big manufacturers would be specifying them on their bikes.

    Now I just want to know how much the i-9 is going to cost.....my guess would be about $500 all in.

  5. #5
    Senior Member grolby's Avatar
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    Hrm. I happen to think that 340% is a pretty respectable gear range. Remember that a typical 70's 10-speed (with 39/52 cranks) had a gear range of about 267%. If we're generous, and give it a 34-tooth freewheel cog, that 10-speed has a range of 324%. Not really suitable for touring, but pretty good for anything else, I think. No, it's not at the 500%+ range that a derailer system can manage, and I think that's a good reason to prefer derailers for some purposes. It is getting closer, though, and for most applications, 340% is as much as anyone could ever need, I think.

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    I'm one of the posters from the other forum and I'm glad to see a bit of discussion here also. I'm happy to see some new products coming out in the gearhub world. The Rohloff thus far is the best but it is pretty expensive for average cyclists. The nexus premium 8 speed with its ultegra level bearings and seals is a nice improvement over the older nexus 7. Hopefuly Sram's new i9 will be an improvement over the Nexus 8. Sram has gotten rid of the external click-box on the i9 so it should be a little more durable. Somepeople have complained of less than perfect shifting with the older sram 7 speeds so hopefuly they have ironed out any shifting problems. Since sram offers its dual drive with disc brakes maybe they will see fit to offer discs on the i9. Since the dual drive is basicly a three speed gearhub with a cassette mounted on the end. Maybe this will spur Shimano to offer discs on the nexus. They are all ready available aftermarket. Hopefuly both manufactors will see the light and start offering roadbike style shifters for their gearhubs. Think ultegra level 10 speed brifters. I think a gearhub on a light touring or road bike make sense for a lot of people. As of yet shimano does't recomend the nexus for offroad riding. Not sure if sram will rate the i9 durable enough for off roading. With the available sprokets and chainrings it is ez to gear a nexus8 or i9 from around 30 gear inches to 100 gear inches. Which is good enough for me. Some others may need more range. Overall I think gearhubs offer most cyclists a durable low maintenence choice and I'm glad to see some new products coming out. Hopefuly they will be improvements to what we already have.

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    Since the dual drive is basicly a three speed gearhub with a cassette mounted on the end.
    This always impressed me as the worst of all worlds; the weight and inefficiency of an internal geared hub coupled with the complexity of a derailleur system. The only time its usage made any sense was on bikes (like some Bike Friday models) that couldn't use a front derailleur.

  8. #8
    Senior Member kf5nd's Avatar
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    I have a Specialized Sirrus... what would be my out-of-pocket cost be for me to strip off all of the derailleurs (Sora, no great loss) and get a sturdy commuter wheel made with this nine-speed hub?

    I guess I would need a nine-speed index shifter... is that any different than a nine-speed index shifter for a derailleur bike?

  9. #9
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    Quote Originally Posted by kf5nd
    I guess I would need a nine-speed index shifter... is that any different than a nine-speed index shifter for a derailleur bike?
    The shifters for internal gear hubs are completely different and incompatible with derailleur shifters. Maybe some day Shimano will make an STI-type shifter for internal hubs but not yet.

  10. #10
    Immoderator KrisPistofferson's Avatar
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    Derailleur gears are great if you keep them clean, but like some of you, I'm waiting for that one internal gear hub that clinches it for me, less expensive than a Rohloff, but with plenty of gears for hilly commutes/touring. I've got a 3-speed for neighborhood runs, and I love the simplicity. Thanks for the links and and good input, everyone. When the right hub comes along, I'll probably switch all my bikes and never look at derailleurs again.
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    QUOTE=HillRiderThis always impressed me as the worst of all worlds; the weight and inefficiency of an internal geared hub coupled with the complexity of a derailleur system. The only time its usage made any sense was on bikes (like some Bike Friday models) that couldn't use a front derailleur.

    It eliminates the front derailleur and improves chain line. A 3 speed internalhub weighs very little. Not sure what the weight difference between 3 chainrings and a derailleur would be versus a 3 speed internal hub and really don't care. It allows the rider to drop into a low gear if they come to a complete stop with the rear derailleur in a high gear. Thus enabling them to easily ride away from their stop. Different people are impressed by different things especially if their needs are different.

  12. #12
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    [QUOTE=HillRider]

    The shifters for internal gear hubs are completely different and incompatible with derailleur shifters. Maybe some day Shimano will make an STI-type shifter for internal hubs but not yet.


    Sad but very true.

  13. #13
    feros ferio John E's Avatar
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    "The Dancing Chain" gives a good account of the evolution of epicyclic gears in Britain (due to the wet climate?) versus derailleur gears on the continent. Epicyclic gears are always going to suffer from excess weight, reduced efficiency, reduced reliability under heavy loads, and expensive repairs. Commuters, beach cruisers, and transportation cyclists have enthusiastically rediscovered them in recent years, but I will be very surprised to see them used in racing or serious club riding, as they were in the 1930s and 1940s.

    One can now configure a 30-speed derailleur setup which provides up to 25 non-redundant, non-crossed gear ratios over any desired range within 20 to 130 gear-inches. That is pretty hard to beat.
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  14. #14
    feros ferio John E's Avatar
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    [QUOTE=carlton]
    Quote Originally Posted by HillRider
    The shifters for internal gear hubs are completely different and incompatible with derailleur shifters.
    ...
    I have shifted a Sturmey-Archer 3-speed with a friction-type downtube lever originally designed for a Huret derailleur. Worked like a champ, and gave me a nice neutral position between 2nd and 3rd.
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    QUOTE=John E

    One can now configure a 30-speed derailleur setup which provides up to 25 non-redundant, non-crossed gear ratios over any desired range within 20 to 130 gear-inches. That is pretty hard to beat.

    That is one heck of a gear spread you have come up with, 110 inches. I guess you had to use a triple chainring for that? I didn't know they made 10 speed cassettes with that much range. Could you please tell me your chainring sizes and smallest and largest cassette cogs? Thanks.

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    QUOTE=John E

    I have shifted a Sturmey-Archer 3-speed with a friction-type downtube lever originally designed for a Huret derailleur. Worked like a champ, and gave me a nice neutral position between 2nd and 3rd.

    Speaking for myself here, but there is something about having a neutral in between gears that I would consider not working like a champ. I don't think that thing is working quiet right.

  17. #17
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    [QUOTE=John E]
    Quote Originally Posted by carlton
    I have shifted a Sturmey-Archer 3-speed with a friction-type downtube lever originally designed for a Huret derailleur. Worked like a champ, and gave me a nice neutral position between 2nd and 3rd.
    We have had this discussion before. The problem is if you don't "center" the shifter properly you can quickly damage the hub. That's why geared hubs had "indexed" shifters way before derailleur gears did.

  18. #18
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    Done a lot of research on this and got a lot of comments on this forum. I concluded that Open pro/Ultegra hub which I use is way more serviceable and reliable for me than going the Internal hub route.

    At the moment with the spares in my shed everything is serviceable.

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    I personally wish they would combine an internally geared and a dynamo hub into one unit.
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    Quote Originally Posted by geo8rge
    I personally wish they would combine an internally geared and a dynamo hub into one unit.
    Wouldn't it be better to spread the weight about a bit instead of having everything in the rear hub?

  21. #21
    kipuka explorer bkrownd's Avatar
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    Quote Originally Posted by amaferanga
    Wouldn't it be better to spread the weight about a bit instead of having everything in the rear hub?
    The big advantage of a combo would be having only one wierdo hub needing a wheel built around it, instead of two.
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    Hmmm not sure I agree there - if you learn how to build wheels then switching hubs and rims only costs you as much as new spokes.

  23. #23
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    Argh!... I was just about to place an order for the Red Band Nexus 8-speed hub; now I need to reconsider because I'd hate for the SRAM hub to come out and make me regret the choice. Converting a bike to use the Nexus hub is an expensive proposition (the following are the cheapest prices I've found and assume that I build it myself):

    Hub: $140
    Rim: $30
    Spokes: $25
    Shifter: $25
    Adapter to mount the shifter on drop bars: $55
    (the shifter is only available in a version that mounts to a flat bar)


    Total: $275!! Just looking at that price is already making me reconsider...

    Having one more gear isn't a huge deal to me (I generally ride fixed so 8 will already seem like a world of options), but I'm getting this to have the ability to quickly add gearing to my otherwise fixed gear commuter for light touring. Going from a gear range of 307% (the Nexus) to 340% (the SRAM) could be useful.

    Ahh.. screw it. I've already mentally committed to the Nexus (and placed an order for the shifter last night) so I'm still going ahead. I'll write a report about it after I get significant experience with it.

    -D

  24. #24
    kipuka explorer bkrownd's Avatar
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    Quote Originally Posted by amaferanga
    Hmmm not sure I agree there - if you learn how to build wheels then switching hubs and rims only costs you as much as new spokes.
    Most cyclists will never build a wheel, and getting somebody else to do it for you is an added hassle and expense.
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  25. #25
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    Whenever internally geared hubs come under discussion, out come the reduced efficiency statements.

    I'm an evidence sort of guy. Is there a study that measured and compared said efficiencies that one can refer to?

    And all these gazzilion gear ratios - how necessary are they? I've been commuting single speed and one thing that became clear is that once a suitable ratio is chosen, it works; what's more, on my derailer bikes I use less and less gears. I enjoy standing up to pedal on hills as I become more practiced to do so. Only when I do roadie stunts like TT do I use the whole cassette. So for that application, derailer for sure, but for all other cases? I wonder if we are being spoiled rotten.
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