NuVinci CVT in a Bakfiets

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Joined
Oct 1, 2006
Messages
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Location
York England
This thing wasn't in my hands very long before I swapped out the old 4 speed Nexus for a NuVinci CVT (Continuously Variable Transmission) hub.

Here's the bike:

080720111370-1024x768.jpg


And here's a slightly closer shot of the back end:

080720111372-1024x768.jpg


So, I'm really just getting used to living with this bike and it's very much a work in progress. The brakes were terrible so the original plan was to run both M brakes via one (dual cable) lever and add a V brake. But it turns out that it's only the front M brake which is failing in its duty - actually its barely capable of stopping this beast on its own - so I swapped out the front brake for another and not much has improved. ....? Strange. Doesn't feel like the cable, more investigations required.

Although I live in a flat area - the 16t sprocket driven by a 36t ring was busting my old knees over the local railway and road bridges - so my old white RaceFace mountain bike crankset has been singlated and fitted - forged cranks .... titanium ring .... Ti Bottom bracket! Funny. Light weight racing parts on a bike which weighs this much!

The cargo box was rebuilt by the previous owner about twice as thick (and twice as heavy!) as it needed to be so the next job is to strip it down and remake it lighter, and with a lower side so my boy can get in it easier.

The NuVinci hub is a revelation, get a ride on one if you get a chance, it's amazing. 350% range of 'gears' or more accurately 'ratios' with no steps. In effect an infinite number of ratios (between the top and bottom). With no steps I'm never between 'gears' - stuck in a gear which is either too low or too high for comfort. I was expecting to sacrifice efficiency for these benefits but there really is no discernable drag in the hub. Awesome. I was impressed by the options - it can carry a brake disc or a Shimano M brake, and obviously a rim brake if you so choose. But the really interesting thing is that it requires a screw on freewheel. Which tells us that it has no freewheel itself. Which tells us that it's a fixed wheel....

The only downside (aside from the hefty weight) is enormous complexity of the installation. OMG. It took an age - and I'm a pretty good bike mechanic. Of course with all things like this the more you do the faster you get so next time I need to change a cable it'll be a heck of a lot quicker.

More pics here: http://www.cyclorama.net/blog/ramblings ... -box-bike/
 
Update: I destroyed the box - it was just too heavy.

Here's the view on my route to work, a bit of a grey day...

P7130168-1024x675.jpg
 
Very cool bike. I am working on getting a NuVinci to use on my Xtracycle. Is that the newer hub or the first generation one?
 
Thanks!

It's the first model hub - I got it 'cheap' after the new one was launched.

If you get the same one I'll talk you through the installation. It's quite a formidable undertaking. Newer hubs are somewhat easier, apparently, and lighter.
 
A new one would be nice but I think mine may be coming via the cheap way too. :mrgreen: :mrgreen:
 
Latest upgrades: Rebuilt box in a mix of 9mm and 12mm water proof and boil proof ply sheet. New weather canopy - just in time for the autumn (fall) rain!

I'm still having trouble with the Shi*-no M brakes which are near useless, the front is particularly bad. I dunno what to do about that short of fitting a V brake on a strap-on. Longer term I'd like to fit a disc to the front. But this is not a bike I want to have a front wipe-out on. Unloaded it doesn't carry a lot of weight over the front so a disc may be too much.... hard to know.

DSC_0199-1024x687.jpg


More here: http://www.cyclorama.net/blog/ramblings ... -troopers/
 
your braking problem come in big part from the lenght of your cable.
you could try to route the cable along the top of the box instead of down and under it.
with the disign of that bike, i dont thik disc brake would creat wipeouts, disc brakes nowadays are very controllable.
 
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