Showing posts with label Dahon. Show all posts
Showing posts with label Dahon. Show all posts

Tuesday, December 6, 2011

NuVinci N360 Friction Comparison - I'm Using Something I learned in High School!

The first article I wrote about the NuVinci N360 that explains how it works is here. In the comments on that article, someone mentioned that internal friction was an issue with this type of hub. When I finally finished installing the NuVinci it was a pretty nasty day, and I didn't feel like putting fenders on the bike just to take it on a test ride. Instead, I took a few minutes with a few different types of bikes and compared the spin time of different types of drivetrains. My totally unscientific method was to put each bike in the work stand, shift into the highest gear, give the crank ten revolutions, and time the wheel's spin from when I let go of the crank until it came to a complete stop. I did this 3 times for each bike, and I will post the average spin and longest spin.

NuVinci N360

The first hub was the NuVinci N360 - After ten revolutions, the wheel averaged a spin time of 19.2 seconds, with the longest spin time of 19.8

That is one blurry photo. Schwinn High Sierra, WTB hub

The second hub was the WTB freehub on my Schwinn High Sierra - that spun for an average of 46.7 seconds. The longest spin for this setup was 48.1 seconds.

Nexus 7

Next I tested a Shimano Nexus 7 speed internal hub. This hub actually had the worst friction of the lot, clocking in an average spin time of 12.3 seconds, with the longest spin at 13.2 seconds.

Like Buttah. 

Finally I put my 1973 Raleigh International in the stand. I picked this bike up from a day laborer a few months ago and haven't done a rebuild on the high flange Record hubs yet, so this was going to be a crapshoot. Average spin time on 38 year old Record hubs? 1 minute 11 seconds, with the longest spin clocking in at a whopping 1 minute and 13 seconds.

In conclusion, while there is indeed some friction drag on the NuVinci hub, it is less than the drag on a Nexus, and not too different than a free hub. If you want to ride without drag, find yourself some Record hubs. Otherwise, I don't find the friction drag on the NuVinci to be a real factor; a Nexus has more drag, and the NuVinci is only 20 seconds or so less spin than a regular freehub. I rode that Nexus for a long time and never noticed a difference. If you are racing, that might be a factor, but if you are commuting, I think the benefits of the hub outweigh the drag factor of the NuVinci.

The NuVinci is $399, available through your bicycle shop.