Modal: Internally Geared

Drop-Bar Nexus

The Modal is a Bike Hugger travel bike concept that folds and toggles between single, fixed, and geared modes. Our latest mode is internally geared with a drop-bar Nexus setup. 

modal_nexus_two.jpg

This wheel was built by Hed for us with Nexus 8 Speed Premium “Red Band” attached to an Ardenne. The Nexus connects to a Jtek bar-end shifter.

The initial ride report is smooth and what we’d expect from the setup. Mark geared it to cruise along the flats and climb Seattle’s steep hills with a 39 x 21. Note that the drivetrain works like a bar-end shifter connected to a Rapid Rise MTB derailer: moving the levers has the opposite effect. It’s reversed.

modal_nexus.jpg

The shifting is responsive, tight, and feels like Ultregra. You can palm the shifter for quick shifting and I got used to the reverse setup within a few shifts. Other internally-geared hubs require you to stop pedaling to shift. The Nexus Red Band does not. I ran through the gears up and down and J-tek’s indexing is audible enought to hear the shift: not vague and sounds solid.

Mechanics have always hacked various drivetrains bits, including various drop-bar setups. While this is technically a hack, it doesn’t shift like one at all. The Nexus of course adds weight, but nothing that noticeable. It doesn’t feel like there’s a boat anchor attached to the back of a reasonably light road bike.

We’ll spend much more time on this bike going into the late Summer and Fall. The next challenge is to travel with it.

More Drop-Bar Nexus Setups



9 Comments

  re:  “Other internally-geared hubs require you to stop pedaling to shift. The Nexus Red Band does not”

Which ones require you to stop pedaling? Regular Nexus doesn’t, nor does Rohloff.  It seems like an odd design flaw, so I’m curious about which hubs you’re discussing.

thanks.

SRAM, Nuvinci, Sturmey-Archer and I thought the Regular Nexus; if not it may have just not been adjusted right. Also note that you can pedal through Nuvinci, it just takes the right touch.

Hmm. I think it must have been an adjustment issue on the rgualr nexus you tried.  I can shift while pedaling on a regular Nexus equipped bakfiets , though I guess I tend to ease off the pedals and avoid shifting under heavy loads.

Yes. I think that’s what’s going on. You can shift, but not under heavy pedal or loads. You’ve probably learned over time to just ease up a bit. I’ve asked Val to come into this thread as a technical resource. That’s what happens with Nuvinci, you learn the right time to twist to shift and it’s nearly automatic.

Indeed, pretty much any shifting system will shift better with minimal load on it (makes sense, yes?).  Many internally geared designs will not shift until all the load is taken off the internal mechanism (older Sturmey, Sachs, etc.), but this can be a very brief pause, and only needs to be a moment when the chain is not transmitting torque; the pedals can still be moving.  All internally geared hubs can be shifted without pedalling, so this a universal failsafe method (i.e., stop pedalling while shifting), though it is not universally necessary.  Some modern hubs (Shimano 8 spd, Alfine) have been designed to shift under load (a bad idea, in my personal opinion), with varying degrees of success.  The Nuvinci can be shifted under load, but the greater the load, the greater the shifting effort required.  As the pressure on the pedals decreases, teh torque needed to move the twist shifter drops, to the point that with no load on the hub, the shifter can be turned with two (or sometimes one) fingers.  Nuvinci makes some hubs for industrial applications that use high powered servos to shift, and they will shift under any conditions.  The bicycle version is mainly limited by the strength of derailleur cables and the human hand. Val

Thanks Val! That helps. I also just discovered that I can drop the whole cassette (well, whatever you call it on internal) with the Nexus.

he means that you can shift across the entire gear-range

Lovely bike.

Question: Does the J-Tek have a cable tension adjuster of some sort built-in? If not, how is the fine adjustment accomplished—I’m guessing an inline barrel adjuster?

Thanks-
Alan

Mark added one. You can see it [in this photo](http://www.flickr.com/photos/huggerindustries/3725177349/). There’s a note.

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