Dynamo Hub Drag Comparison

With dynamo hubs lights and chargers becoming better by the day i ve been getting a lot of inquiries about how to wire up the best hub dynamo system.

Dynamo hub drag comparison. I ve build a son 20r hub with cx ray spokes and 700c kinlin rim recently came out at 875g which is pretty good. Shimano 6 volt 3 watt dynohub. Made by wilfried schmidt maschinenbau in tübingen germany the hub is quiet and is designed to give at least 50 000 kilometers of trouble free riding between servicings. I later noticed that sp pointed out a few corrections in the ctc article which they posted on facebook i contacted charles tsai at intelligent design cycles sp s largest aftermarket distributor to gather some more technical.

The schmidt dynamo front hub or son schmidt s original nabendynamo is extremely reliable and has almost no drag. To put dynamo hub drag into perspective we can compare the 1 5 2 7 slower speeds with a. The new shimano dh 3n72 dynohubs have lower drag than the nx 30 higher quality bearings comparable to ultegra hubs reduced weight and have occasionally been available in both 32 and 36 hole drillings though usually in only 32 hole however we do have some 36 hole 3n72 hubs available. The efficiency of a high quality dynamo hub at low power eg.

Despite it usually running the least amount of drag it offers the 2nd or 3rd most power in all cases with 57 efficiency on charging. The most efficient dynamo hubs when switched on add between 3min 24sec and 5min 47sec to a flat ride over 100km when compared to a regular hub. I have taken the wheel off and will use it when i reaaaaly need the dynamo. I cannot feel the drag with the light off but can certainly feel it when the light is on.

Hub dynamo benchmark comparison. We can find out how efficient a dynamo hub is by comparing its power output and drag at different speeds. The schmidt son28 is incredibly efficient across the board making it the undisputable king of dynamo hubs. This means that when the charger is making between 1 3 watts you can roughly double that figure to work out the drag in watts at the hub.

The rate of efficiency is quite different for different hubs. The charts above show the power created at the dynamo hub by different usb chargers. Does dynamo hub drag really matter. For example at 15kph a schmidt son28 hub provides 1 9 watts to your usb device but will take 3 2 watts of your pedal power see graph above.

A recent article posted by ctc presented results from some benchmark tests comparing the son shimano supernova and sp hub dynamos. Not only that but son28 hubs are reliable and use high grade skf sealed bearings to help them run smoothly for more than 50 000km.