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  1. #1
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    Why doesn't someone build up something like this?.....

    It seems to me that the Shimano Nexus 8 speed internal hub is fairly begging to be built up onto a SS MTB frame! Combine this with something like a Redline Monocog 29'er, or a Surly Karate Monkey, and it seems to me you'd have the best of both worlds. To wit, the lack of derailleurs, with their attendant chain slap, noise, and fragility, AND some gears to select from, when you'd otherwise be walking, or spinning out. Are there any technical reasons why this would not be doable, and has anyone here tried it?

  2. #2
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    because then it wouldn't be a single speed
    Disclaimer: I fix bikes for a living.

  3. #3
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    Quote Originally Posted by dwnhlldav
    because then it wouldn't be a single speed
    True, but it seems like it would still have most of the advantages (ie, you could still really stand on it) of a SS, but be a little more flexible.

  4. #4
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    If I were to do it I'd go for the 3-speed version, but any of those things weigh a ton, and right where you don't need the weight. I'd rather spin or walk, thanks.

  5. #5
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    Built up a Nexus 3 speed

    I put one on a bike for my wife for around town barhopping. It has lots of drag,is heavy and the shifting mechanism is weak at best. It is ok for casual "around town" but i do not think it would last very long in the real world of mtn biking. I would also have reservations about the amount of torque it could handle.
    The Rohloff is the only internal geared hub around that can really be used..i tried to love one a few years ago but "divorced" it rather quickly....heavy with lots of drag..
    I may however use the Nexus 7-speed for the next "sidecar bike" for barhopping...

  6. #6
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    These replies make a lot of sense, thanks! Guess I'll stick with SS. I'm asking these questions because I'm thinking of building a SS, want to get it right from the get go.

  7. #7
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    Quote Originally Posted by Doggity
    It seems to me that the Shimano Nexus 8 speed internal hub is fairly begging to be built up onto a SS MTB frame! Combine this with something like a Redline Monocog 29'er, or a Surly Karate Monkey, and it seems to me you'd have the best of both worlds. To wit, the lack of derailleurs, with their attendant chain slap, noise, and fragility, AND some gears to select from, when you'd otherwise be walking, or spinning out. Are there any technical reasons why this would not be doable, and has anyone here tried it?
    it's been done... try a search in the drivetrain forum IIRC. Bottom line- it's not meant for the rigors of offroad, that's what rohloff is for


  8. #8
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    Nexus hubs are not MTB hubs and they are not SS hubs, so why is this posted in the SS forum on MTBR?

  9. #9
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    we might as well just go ahead and motorise our bikes if we want less time walking. The thing with Singlespeeds is you have the bike and ride it if you don't get up the hill you walk and there's no excuses like 'I was in the wrong gear' etc. then there's the maintenance issue, while we spend a lot of time on our bikes not much of it needs to be actual maintenance. the one good thing to come of the Nexus hubs is the Shimano chain tensioner so these hub gear systems can be used on vertical dropout frames.
    Do people think you are strange??

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  10. #10
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    Quote Originally Posted by Doggity
    These replies make a lot of sense, thanks! Guess I'll stick with SS. I'm asking these questions because I'm thinking of building a SS, want to get it right from the get go.

    My first response was loaded with sarcasm if you didn't notice, this one is more serious.

    If you are thinking of building a Single speed why are you looking into internally geared hubs? It isn't a single speed just because it has one cog and one chainring.

    Like everyone else said, only the rohloff will handle off road.

    The shimano ones need rebuilding, more often then not under hard use, and it is not fun.
    Disclaimer: I fix bikes for a living.

  11. #11
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    Quote Originally Posted by PeanutButterBreath
    Nexus hubs are not MTB hubs and they are not SS hubs, so why is this posted in the SS forum on MTBR?
    Er....because I was asking about building one into a SS frame? And Down Hill Dave, I didn't miss yer sarcasm....I just chose to ignore it. But thanks all for responses. I am not new to SS; I just stupidly sold mine, gotta start again. I am not naive about the joys of SS; I just have seriously shot knees. Maybe a 29'er in 32/20....

  12. #12
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    Check out the new SRAM I-motion. It's supposed to be more durable than the nexus. As is the Shimano Alfine, now available with disc. Several threads in the drive-train forum about this topic.

  13. #13
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    If I wanted to turn an SS frame into a lamp, I would ask in a lighting forum.

    If you want contructive feedback on a internally geared hub, I suggest asking in the Everything Drivetrain forum.

  14. #14
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    a gearhub would be too much technology on my bike.

  15. #15
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    Swobo

    Does one.

  16. #16
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    I don't think the OP's question is too far off topic for this forum. The same considerations for setting up a single speed apply to an internal gear hub: chain tension device, chainline and maybe cranks. So here's some constructive feedback.

    I bought the nexus red stripe hub last year to put on my cross check commuter which sees pavement and trails sometimes. I swapped it over to my karate monkey to see how it performs off road. Rode it 3 or 4 times on my usual trails.
    Pros:
    • Gears for riding to the trailhead, with the simplicity of a single speed drivetrain (except for the shifter)
    • Good gear range


    Cons:
    • Heavy
    • Shifter performance (or lack thereof). Think of a lousy digital camera--just when you got the shot, you hit the shutter--3 seconds later "click". You could anticipate the hill and shift accordingly, but it would take me by surprise when it actually shifted.
    • Never felt like a single speed even when I left it in one gear, hub engagement was pretty poor, plus the weight in the back.


    Durability over the long haul is still a question, but I can say it's held up fine for my short experimenting.
    Instead of putting it back on the commuter, I went 1X9 with the commuter and put the nexus wheel away for a while. But, I just re-installed it on the KM which is now going to be my bike-to-the-beach-pull-the-kayak utility bike. I have a different SS now that I ride most of the time. There's the single speed content.

  17. #17
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    Quote Originally Posted by arkadi
    Check out the new SRAM I-motion. It's supposed to be more durable than the nexus. As is the Shimano Alfine, now available with disc. Several threads in the drive-train forum about this topic.
    Had a rep drop by with a bike with the I-motion. in plain words.... S _ _ T H O U S E!

    Take the weight of an Alfine or Nexus, make the shifting really clunky and slow. Bam thank you Sram.

    Of course I can't make comment about durability, but it truly feels horrible when shifting in comparison to Shimano.

  18. #18
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    Not a mtb, but ...

    ... how 'bout a cross bike?

    I have often wanted a two-speed fixie hub for offroad. About the best solution I can think of is two chainrings, a disc/cassette hub with two cogs, and drilled DX cog. A (freewheeling) gear to get to the trail, an SS trail gear, and a fixed trail gear. Haven't built it yet, though.

    -Rob.

  19. #19
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    My buddy just did that to a 26er Kona Explosif, threw in a Alfine Hub in an attempt to keep a bit of the SS feel but the ease of gears. The jury is still out on the Alfine and at this point in time he has only done some trail runs and no real 'harsh' offroad.





    Hopefully he will offer some off-road feedback soon. Initially the only thing that I can say is that the rear wheel was heavier than the small Explosif frame.

  20. #20
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    Quote Originally Posted by robcycle
    ...I have often wanted a two-speed fixie hub for offroad....A (freewheeling) gear to get to the trail, an SS trail gear, and a fixed trail gear...
    I think this is a relevant question because this forum is where to find the expertise in single chainline.

    I've tried a Nexus hub on an MTB. It feels tail heavy but ok, but I much preferred my single speed.

    I have built up a cross bike with a S-A 3 speed hub which gives 49/66/87 gear inches, ie I have a gear for the trail, one for the road, and a high one for the road.

    It's a well proven device with over 100 years in production, relatively light, and has a reliablity that can cover over 50,000 miles. It is tailor made for SS users because it was designed for our frame type. Probably not good for the wreck everything types though.

    The Sturmey Archer hub is now available in 130 spacing so it's worth considering for those of us who need to cover considerable road distances to get to the trails. There's no disk brake option, but an adapter could be put on the version with the screw on brake mount.

    My frame is an On-One Pompino with 120 rear spacing that gets used SS a lot of the time on the road, but I have ridden quite a lot of singletrack on it.

  21. #21
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    I put a 3s SRAM Dual-Drive hub on a Niner Sir9 (with EBB).... it works but I have ridden it only a handful of times.

    Sorry, this action shot is the only pic I have handy.
    <img border=2 src="https://gallery.mtbr.com/data/mtbr/500/flying.JPG">

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