safer mounting : Trailing edge of rotating wheel, as top goes forward , the Bottle dynamo would Be ahead of the fork blade , and ahead of the seat stay tube

that way when it may get loose, rotating wheel wont tend to push it into the spokes with Forward Motion Forces ..

Fishman473, I can give you more reasons for not having one than having one for touring but it sounds like you need an excuse so go ahead. I've got two bikes with SON Dyno hubs that are used mostly for commutting and like them a lot especially for the tail light. I wish the headlights had a strobe function for daytime riding. I don't have experience with charging devices but my understanding is that you'd be charging a spare battery for your iPhone more than charging it directly. Others will correct me if I'm wrong.

It may be the best clamp, free of bending, but can still rotate.
Braze-on tabs and canti-brake-mounts are better

It does have a set screw so I'd think it would stay put fairly well. Of course a lot of folks would balk at marring the finish with the set screw. Also I definitely wouldn't use it on a carbon fiber stay.

That would definitely seem to be the case for frames where one of those options are available, but a lot of frames have neither.

If the pivot axis of the dynamo is vertical, then leading edge mounting will maintain better pressure on the drive roller. Clamps, as you say, should always be mounted on the trailing edge for safety.

Let's say I'm already convinced -- looking for USB power, rather than to directly power lights. What's a good resource to look at to figure out all the bits and pieces I'll need?

USBWerk or sinewave

I can make one for you or send you the parts list and schematic its really easy, your choice. Parts are about 22$
You can see it in this video http://youtu.be/pJmhKT-Fe18
My main site bicycle365.com is down til next week for an overhaul but there is a lot of info on the box and system there as well.

Do you want to solder one together or do you want to buy? I soldered one together for under $10 in parts. But if you don't know how to do that, you are better off buying a complete one.

In addition to the ones mentioned by Bmike, I think B&M now makes one with a USB port built into a headlight. If interested, check Peter White's website.

Seriously? You need convincing? Cmmmmmm
I've been using dynamo hubs for as long as I can remember (I'm in my 40's) beginning with a Sturmey Archer GH-6 (I think it was called) which only gave out a measly 1.8 watts at 6V.
It was enough to power a bulb that allowed you to be seen but not good enough to see much yourself.
Then came the Edelux headlight which was just "WOW", a few years back.
I upgraded to a Son28 which was a fraction of the Sturmey weight and put out a lot more watts.
I then invested in the new at the time technology of an E-werk and cache battery.
The E-werk/Son28 keep my iPhone 5s charged as well as my Edge 800 gps.
I then bought a Petzl Tikka 2 headlight torch for around camp which has a "Core" usb rechargeable battery which you guessed it is kept topped up via the E-werk.
I'm about to buy a Sony camera for my touring trips which once again is able to be charged via usb (take a bow E-werk/Son28)
I no longer bother with a car, so my bike is my means of transport as well as my recreation and means of holidaying.
My dynohub is my favourite possession and is used for some purpose almost every ride be it lighting on my trips to the shops or just keeping my phone topped up whilst I take a spin to the local beach.
I also keep a large cache battery for "just in case of emergency" but I think its pretty redundant as my hub keeps on top of everything as long as I'm careful with my prioritising the order of charging my items.
I'm only surprised anyone is unsure but then here in Australia towns can be many days cycling apart and having a charged phone could be the difference between life and death should one be involved in an accident/snake bite etc.
The sheer lack of thought with regarding remembering to buy batteries is really a joy.
In fact I'm so sold on dynohubs I built up a second dynamo hub wheel just for my Extrawheel trailer.
I can if you wish supply a link to someone who has added vanes to their Extrawheel trailer so they can turn it upside down at night and any breeze turns their dyno hub wheel (in trailer) and charges their stuff whilst they are asleep in their tent.
My iPhone needs around 4 hours riding to add a significant charge (from quite low to nearly or completely full) depending on speed.
Less charge on slow hilly country and more on flat faster roads.

You'll probably be better off with a powerbank you can charge every 3-4 days from an outlet and/or solar. I've been using an SP PD-8 dynamo, B&M Luxos U for USB output, and a GoalZero Guide 10 AA battery pack. Hooking my very cheap Android phone directly into the USB output will recharge the phone at about 1-2% per mile. However when I'm in a speed range of 5-9mph the phone will constantly start and stop charging which I doubt is good for it. Routing USB power to the Guide 10 to use as a cache battery is better, but a 25 mile ride is only enough to charge my 7" tablet 3-4%.

Having components from so many different vendors makes troubleshooting difficult, and needless to say it's an expensive option to ride all day for what amounts to about $.02 of electricity from an outlet.

Besides the Peter White site I found these helpful:

Cycling About ? Power Resource for Bicycle Touring: Dynamo Hubs, Solar Panels, Power Supplies and Batteries
Bicycle lighting, mostly powered via dynamo, and USB power from dynamo
Hub Dynamo Systems For Bicycle Touring: Part 2 » Tour in Tune

I use the best of both worlds, which is the modern replacement for a hub dyno - can easily move bike to bike and no additional drag when not in use. Can use with any hub you already have - VELOGICAL RIM-DYNAMO It weighs just a little over 2 ounces and is smaller than a 35MM film canister.

http://files.webbuilder.hosteurope.d...v2_srgb_lr.jpg

What is a dynamo powered flashlight? Since you contrast it with a battery powered flashlight it sounds like a flashlight that gets its power from a dyno? You pedal the bicycle to make it produce light? Like a headlight presumably. What is it in your car for? If you "need it" then what do you do with it?

I am using "dynamo" to refer to a device that transforms mechanical energy into electrical energy. There's a good variety of flashlights, radios, flashlight-radio combinations, and other sorts of emergency preparedness gear that incorporate a dynamo power device, just because batteries are not very good for emergency preparedness gear.

I have an old NightStar flashlight in my car, that uses a shake dynamo: Shake Flashlights Info

In my storage unit I keep a different dynamo flashlight, that uses a crank. That storage unit is in a cavernous warehouse whose lighting is controlled by timers. When I come into the warehouse, I crank the timers to get about half an hour of lighting. I walk back to my storage unit, get deep into the boxes trying to find something, a half hour elapses and the warehouse lights turn off. Very happy to have my flashlight with me!

A few years ago my partner's son was practicing Aikido with a group. They met in a barn way out in the country. To pick him up I would have to park down the road a way. It could get mighty dark out there! That flashlight in my car got a lot of use. I have used it when I got a flat tire, getting the lug wrench properly onto the lug bolts, or the jack squarely under the car, etc. Can be good too if you really get stuck and have to walk to find help. Oh yeah I carry chains in the trunk. They are tricky to put on the tires. The flashlight is useful for that, too, to see what I am doing down there in the snow.

Thanks for posting the info on this, I was unaware of these. Looks like a much better option than bottle dynamos. Does it make wheel removal more difficult or does it move out of the way so that it does not get in the way?

I already have a dynohub, thus am not shopping for one now. But if I wanted to add one to a second bike I might consider this instead. Since it would work on different size wheels, I could fit it to my foldup bike and later switch it to my 700c bike if I felt the need for it.

It is ideal for a dyno you use occasionally which is the case for me. If you always use it you might be better off with a hub unit. This takes about 10-15 minutes to move from bike to bike depending on the mounts and how you have it set up. It spins at much higher RPMs than a hub unit which makes it easy to build as a small (and lighter) unit and it also gives it a mechanical efficiency advantage at higher RPMs. I mount mine on the rear and I have it there because it is audible, but to me not annoyingly so. It does not slip at all in wet weather and you would not want to use one if you ride in a lot of thick mud. You totally disengage it when not in use so no trouble at all when you want to pull off the wheel. I have the Trekking model powering an Edelux II. It is a great combination. It does get a bit dimmer when pedaling up a steep hill at 4 MPH, but I do not need as bright of a beam then either. It is very well made and not too bad to install, but you have to order the right type of mount (or mounts) for how you want to install it. I like the fact that I can mount it front or rear and use what ever hub and rims I already have, no need to rebuild a wheel and idle my Phil Wood hubs. I also like the fact that it is completely disengaged when not needed so no additional drag (unless you want to consider the very tiny bit of wind resistance for the unit attached to your frame).

Here is a post on another discussion on the Velogical. There are a lot of skeptics (that have not used it) and me, an actual owner of one. http://www.bikeforums.net/electronic...mbination.html

Further down in the post you can see my power output curves. The unit I have puts out 2 watts at about 14 kph and 6 watts ah 23 kph. Not too shabby! They also make a higher output model for slower riders or ones that need to charge GPS or run multiple headlights, and a lower output model for faster riders that do not want to ground excess power back to the frame (which is what happens with most larger hub dynos).

Thanks for the additional info. This time of year my studded tires probably drown out any noise that your rim dynamo could ever make.

If they are hand made by the seller, I can see that it is unlikely that I will ever find one on a good sale price.

I got my SP Dynamo PV-8 dynohub in April 2013, but if I was aware of these at that time I would have considered this instead. That way I could have one that would fit on my 700c bike, twp 26 inch bikes and my foldup.

My hub is silent. I think some people complain of a low frequency vibration in the handlebars at very slow speeds with some dynohubs, I have never felt that with my hub but I have a heavy rim and 2.0 or 2.25 width tire on that rim, that might dampen any vibration. I can't feel any drag at all with my hub, but my hub is rated to have less drag than most others. During spring and summer I am running one Lumotec Oval with a switch (discontinued model). During fall and winter when the sun sets earlier and I am more likely to be caught out in the dark, I run two Lumotec Ovals that have no switch (also discontinued models) in series and leave them on all the time. Even with two lights, I still do not notice any drag.

I do not think they are likely to be on sale anytime soon. They are sold direct from Velogical, the manufacturer. I think I paid about $150 which is still a lot less than you typically pay for a good hub dyno, especially after you have it built into a wheel.

A hub dynamo and cache battery lets me recharge my iPhone and my Garmin Edge 810 so I am never without navigation and communication assistance. I like it that way. Your mileage may vary.

That's what I do too. But the way things are improving with battery technology, you hardly need the dyno anymore. My cache battery is currently a mophie juice pack powerstation xl. I can get 6-8 full charges of my iphone on a charge of that cache. A charge will typically last me 24 hours even with a lot of GPS, etc. Since I'll stay in a motel every few days touring, or at least find a painless plug-in opportunity, I would not really need the dyno.

It's nice to have but less and less important.

Edit: I use only the iPhone, no Garmin Edge

I can't speak for the OP, but this seems to be a tempting approach from my perspective, at least for some tours. Looks like it weighs just under a pound, and considering that even with a dynamo hub, one would most likely still want a cache battery of some sort. So, using this and dropping a dynamo hub altogether would lead to a weight savings. Given the large storage capacity of 12,000 [mAh] I'd be able to go a few days between charges even with daily use of a tablet.

I agree a cache battery would work for most people, providing power between charge locations.

I also use a powerful headlight and taillight powered by my dynamo as daytime running lights, because I am concerned with auto drivers here in the US.

In addition, I keep my iPhone and Garmin Edge 810 fully charged up all day.

When not running the lights or electronics the dynamo tops up the cache battery, so its always in use.

I don't notice any extra pedal effort, and the weight is not a problem for me.

All in all I think dynamo and battery are a good combo.

Thanks for all the input everyone.

What' I've decided to do was to get the VeloLogic rim Dynamo and the Sinewave Revolution USB charger.

This should allow me to charge when I want/need to and shut the generator off entirely when I don't. I can swap it to another bike easily (EDIT: or the other wheelset on the same bike) if I'd like to use a different bike on a trip. If I want to add a light into the system later I can. Its also slightly less expensive then a generator hub and a lamp that also charges USB devices.

EDIT: This option is also lighter than a dyno hub, even if you figure in a ~3000mAh back-up battery for charging on days off the bike.

Looks totally cool! The 90 grams for a mounted unit is really great. Would love to hear a real-touring-world report on how it performs.

My back-of-napkin calculations:

• device rated 6v, 1.5 watts at 15 kph
• charge smart phone = 10 watt hours
• 7 hours of riding should do it
• reality???

6v at only 1.5 watts is not USB power. Its only 250mAh , USB minimum is 500mAh at 5 volts. The 6v to 5v drop gains a little overhead but the ac to dc loses some.
The sinewave ( any conversion process) is not going to be 100% efficient so you will lose some there.
SON28's and other dynos that meet the German standard put out 3 watts and that's barely enough. I use a pretty efficient converter and can barely squeak out 500 mAh with a gen putting out twice as much.
Not all devices will accept a less than mimimum charge current (Apples especially) but I would test your device to see if it will accept a lower charge current first, and see if 1.5 watts is within the input threshold of the sinewave .

EDIT!!!
From the sinewave site
" Will the Revolution work with my dynamo?

Yes. The Revolution can be used with any hub, bottle or spoke dynamos. Any standard 6V/3W dynamo will generate enough power for the Revolution to charge your device. The less-common 12V/6W dynamo can be used as well.