This is a shameless attempt to save the the most advanced civilization in
history from imminent self destruction by eliminating carbon emission,
dependence on foreign sources of fuel,obesity, hypertension and diabetes.
Cycling accomplishes all those things at once and helps us develop a better
understanding of ourselves, each other and our relationship to the cosmos.

Oh, horse puckey!
I like to ride bikes, have been doing it all my life.
The rest of that crap is just a fringe benefit,
and the blogosphere gives me a chance to share my interior
monologue with virtual rather than imaginary friends.

Tuesday, March 8, 2011

Installing the Nuvinci hub

   When I got the new wheels in for Byron (the Mixte) I was a little intimidated by the hardware for the Nuvinci hub.  I had wrenched a few weird things but this had a single shifter with two cables running back to the hub and this funny looking "shift interface."   The first thing I did was enquire on the Mechanics forum at bikeforums.net to see if anybody had any experience and advice.   I received several helpful comments which, when compiled, amounted to "quit being a man and read the instructions."  So I did and the directions are very clear and simple.  After a couple of aspirins and a nap, I decided it best to just look at the components.
    The directions are clear and the installation is surprisingly easy!  After installing the cog of choice, one must turn the barrel adjusters completely clockwise while looking them in the barrel.  Then install enough housing to reach all the way to the rear hub, providing enough extra for handlebar turning and wheel removal. Once the housing is installed pull one cable all the way taut through the housing.  If the indicator line on the shifter goes flat, install the small anchor nut 117 mm from the cable housing.   If the indicator line goes curly making a hill shape, install the other, latchey looking, anchor 114mm from the cable housing.   Pull the other cable out all the way and install the leftover anchor.
    The interface itself fits easily in the hub, it has splines on the back which slip right into the splines on the hub and locks in place with a small lockring.  It can be easily positioned so it is in line with the chainstay.   There are two slotted ferrules to fit the ends of the cable guides and the cables only fit one way if the anchors are positioned properly.   The one with the small anchor goes through the top ferrule and around the unit to a small catch, the cable with the larger anchor goes through the bottom ferrule to another catch.

The latch mechanism closes over the first catch for additional security.  What amazed me was the simple fact that I was done!  In the case of the Shimano Nexus hub, there are a series of little dots and plastic pieces which have to be aligned both before and after installation.  In this case, the mechanism is simply two cables turning a wheel which turns the splines in the hub.  Of course I'm oversimplifying this intentionally, but once you follow the directions and look at it, this is one incredibly simple mechanism.  The cables provide counter tension for each other and you don't end up with umpteen minute plastic pieces relying on springs and levers which inevitably wear out and break.
   Now with full housing through the length of the cable travel, routing the cables through the frame can be an issue.  I took a pair of dountube cable stops, removed the barrel adjusters and ran the housing right through the stops for a start.

That left me with the problem of anchors below the bottom bracket.  Ignoring my mismatched socks, I got some zipties and first anchored the cables together on the chainstay.

Then I used a couple plastic anchors

for zipties by trimming the excess plastic from the sides and screwing them in place using one of the waterbottle bosses, and the the anchor bolt for the bottom bracket shell.
The anchors hold as many as 4 zipties and make it very easy to anchor the cables securely and discreetly under the bike.
Again ignoring my mismatched socks, I trimmed all the ties closely and was done.   I think that when it's necessary to remove the real wheel, the tie on the chainstay can be cut and enough slack pulled out to make tire changes fairly painless.  The cables can be pretty easily removed from the shift interface,  but I honestly don't think it will be necessary unless repairing the wheel itself.
    Now that Byron is on the road, I am more than ecstatic over the performance of this hub.  The only adjustment which needs to be done can be performed by removing cable slack through the barrel adjusters.  Beyond that I don't anticipate any problems.

2 comments:

  1. Thank you! I'm hoping to put one of these on my Raleigh Super Course mixte.

    I love Byron's name on the chainguard.

    ReplyDelete
  2. Thanks! I couldn't resist.

    ReplyDelete