Dynamo hubs generate a constant power source for front and rear lights or diverted to power USB charging for items such as phone and GPS. Dynamos have been popular with distance cyclists who need reliable lighting for all night cycling in any weather conditions for some time now. But as commuters, people training and cyclist just wanting to be seen considering a dynamo means no more remembering to charge your batteries, having batteries die or possibly forgetting your lights all together is in the past.
Always the first complaint is the upfront cost. About $100 to $290.00. There are many rechargeable lights in the same price range and even higher.
Its safe to say there are 2 front runners in respect to dynamo hubs.
SHUTTER PRECISION HUB DYNAMOS
Shutter Precision 8 Series Dynamo. Hub alone $130.
Review of the SP is coming I just built the wheel and am going to use it with a mountain bike specific dynamo headlight. Check back.
Schmidt's Original Nabendynamo (SON)
Schmidt Dynamo front hub or SON (Schmidt's Original Nabendynamo) wide body. Hub alone $282.00.
Recently I built a pair of these on Velocity rims to be used with the Busch & Müller IQ-X headlight, Busch & Müller Toplight Line Brake Plus rear light and rolling on Compass Rat Trap Pass tires.
The SON front hub is beautifully finished.
First ride impressions are fantastic for the entire set up. For the average rider all that is needed to know is just plug the 2 contacts to either spade connectors on the hub (which can be on the right or left side of the fork) and roll off, the lights come on even at very low speeds. USB charging will not happen at low speed but will happen at about 15mph. Output of modern LED and lens lights are over 100 lux or 1200 lumens at 20km/h (12mph).