Hub Dynamo Comparison Tests?
 

A few years ago Bicycle quarterly tested a number of hub dynamos and compared power output and rolling resistance. Since then there have been new hub dynoamos on the market. Does anyone know of any comparison tests?

This is the only one I am familiar with that is in depth on output, drag, and also includes SP hubs. I do not think much has changed since published in 2012.
https://www.cyclinguk.org/sites/defa...ub-dynamos.pdf

I am not sure how to compare the Shimano hubs, they appear to have lots of specific part numbers and I have no clue if their output and drag numbers vary very much from model to model. But the other manufacturers appear to be pretty consistent with a shorter list of model numbers.

Thanks for the link. It seems that the SON hubs are still the best. I've been using the Kasai hub and have been satisfied with it, but I'm wondering if the SON hubs are the much better to justify the cost.

I only recently became aware of Kasai hubs, they look very much like SP, thus I wonder if they are an SP that is re-badged.

I have bought two SP hubs, one in 2013 and one in 2017, both were new. And I bought a couple of used wheels with Shimano hubs from a bike charity that received them from a manufacturer. I do not see any reason to buy the higher cost SON based on my experience.

It seems the test data all came from Andreas Oehler and Olaf Schulz, and i suspect they are from this (german) magazine: fahrradzukunft . de
The respective german article (well you probably understand the figures) is here (Since i still cant post links --> go to fahrradzukunft . de --> archive and search for "nabendynamo", tests are in issue 1 and 14, and the latest is from 2012. Being from germany where hub dynos are wide spread, i know that there has not happend much since then on the hub dyno market. SP dyno are periodically rebranded by different companies, where maybe the sealing might be modified, but to my knowledge not the power generation parts.

There is a newer rim dyno, with efficiencies similar to hub dynos: Velogical rim dynamo, with different version (sport, touring, power generation). They were tested in the same magazin, issue 18, and these data are from 2014


There is one reason to buy the SON: If your bike is exposed to constant temperature and humidity changes in winter, from a "warm" basement to a cold, humid environment, the hub cools down, and the pressure inside the hub decreases. Pressure differences are then compensates by ingress of humid air from the outside. I killed a Shimano hub (3N71) by exposing it to often to these temperature changes in winter, the bearings (and the magnets) were heavily corroded...I still replaced the shimano hub by a new one, since i didn't want to throw away the pretty new spokes, but my bike is now outside the whole winter

the SON dynos have a system to compensate the pressure difference between dyno hub and environment to avoid ingress of humidity. The use a small, simple oil filled tube. Furthermore the SON allows change of sealings and bearing. Changing the bearings at a shimano hub is nearly impossible. So over many years, the son becomes cheaper (and more eco-friendly)

I'm not sure about the current status, but Andreas has worked for Schmidt since the early 2000's. He and Olaf have authored a number of articles on dynamos, possibly taking advantage of the test gear at Schmidt?? Their test methods and data have appeared to be quite good (speaking as an electrical engineer myself).

Steve in Peoria

moved, sorry, wrong thread.

According to a most recent article, Andreas is still at Schmidt. The test data for the articles were acquired at Olaf's (private?) laboratory. Being a chemist, i don't understand too much (electrical) engineering, but i agree, their data look very solid.