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I know we're all big on lightweight bling etc, but seriously, if dynamos work, why don't we all have them for lights etc? or are they just a bit pony, unreliable and badly designed? I've always fancied one, but they don't seem to be stocked that much im LBS's?

I think it's because cheap systems probably dislike off-road riding a great deal and aren't great, while expensive systems are really quite expensive. For a 2 hour knock around the woods I suspect batteries must be better. For the Dunwich Dynamo then a dynamo is probably the best bet.

I've got a Shimano Dynamo hub built into a XM719 and it's great. Adds about 400g over a normal hub though.
I'm just waiting for someone to build a 20mm thru-axle dynamo!

I know we're all big on lightweight bling etc, but seriously, if dynamos work, why don't we all have them for lights etc? or are they just a bit pony, unreliable and badly designed? I've always fancied one, but they don't seem to be stocked that much im LBS's?

It's because they only became any use when the combination of the latest LEDs with more efficient dynamo hubs meant that you could get a usable amount of light without massive drag. Even now, with the exception of the Supernova lights (very very expensive, very bright) they're not as bright as the most expensive battery powered offroad lights. They are great for on-road riding, but probably not quite there for technical off road, especially given how bright and cheap the newer battery powered LED lights are. Homebrew lights are dead easy to build though, I guess some people will build some very very bright homebrew dynamo lights some point soon.

They also have a bad reputation based on people who have used ancient systems which rub on the tyre, cause massive drag, don't work well in the rain and generally aren't very bright either. It is hard to believe that they can be so good when you know how bad the old ones were.

You also have to rebuild your front wheel, which is a bit of hassle.

Joe

Hub dynamos are great. I want the wheels on my cargo bike to die so I can justify getting hub gears/brakes/dynamo wheels, but they're rather on the beefy side and are refusing to die.

Dynamos are limited to 3W so will always struggle to match some of the higher end systems.
But I'm tempted to try this this winter, 12V 6W 🙂

Wow. 😀

I love dynamo systems – having them on my touring and commuting bikes.

But one of the scariest rides I've ever done was using a dynamo lamp along an off-road cyclepath – give me lots and lots of lumens!

Anyone remember carbide?

Dynamos are limited to 3W

Hub dynamos are only limited to 500ma actually. So like you showed in the pic, you can get any wattage by using multiple LEDs. There is someone I think on candlepowerforums or mtbr who has built a 6 LED one that is something like 15 watt of stupid brightness (dimmable by switching off some of the LEDs).

I built a super duper dynamo rear light, just used a cheap rectifier and a red Cree LED. Dirt cheap, jolly bright, and the automatic current limiting effect of the dynamo seems to stop it blowing out which is neat. Slightly less efficient than it could have been, due to the rectifier, but still not noticeable drag.

Joe

Good point joe, they are current limited. Apparently they get more efficient as the voltage climbs.

Not so tempted now though – checked the prices and another IQ Fly is around £80 🙁 I paid about £50 a year ago.

A dynamo powered troutlight would be very cool, but all the dynamo hubs are still QR

Not so tempted now though – checked the prices and another IQ Fly is around £80 I paid about £50 a year ago.

£56.71 at dotbike (I assume for a second light, you don't need a standlight or automatic turny on-off, as you're only going to want to run it some of the time?)

http://www.dotbike.com/ProductsP4015.aspx

The Cyo is £73.
http://www.dotbike.com/ProductsP6841.aspx?utm_source%3dinternal%26utm_medium%3dsite%26utm_campaign%3dDFR

What dyno hubs do people use? Im about to build up a new set of touring wheels and tempted by changing to a dyno set-up.

40 euros from germany though, I may try that route again.
2x Cyos would be cool 8)
I think I might go for another IQ Fly when this comes out….I quite like the look of this

I use this one stato, it's the only shimano disc hub:

shimano-deore-xt-qr-dynamo-front-hub-6-olt-disc-brake-mount-36-hole

Im not bothered by disc mounts as its for my commuter/tourer which runs canti's.

That said i suppose it might come in handy for future-proofing. Are all shimano dynamo hubs the same internals? ie. can you run any Dynamo light off any hub? (im not very knowledgeable on dynamo stuuf)

I'm using an old Shimano dynohub on my audax bike. Very reliable and it was dirt cheap. It throws out plenty of light for night-time country lanes and tracks. Not so sure it would be any good for more sketchy & technical stuff though.

Don't forget you can turn last year's knackered/unwanted Tesco torches into mini 3W dynamo lights 🙂 ……….

http://homepages.nildram.co.uk/~talizmar/xntrick/luxeon.htm

&

http://yacf.co.uk/forum/index.php?topic=12262.0

The Shimano DH-3N80 is the daddy of dynamo hubs. It is lighter weight than the other ones, and more efficient (meaning less extra effort pedalling), oh and lighter than the older ones (500g hub weight).

http://www.cyclestore.co.uk/productDetails.asp?productID=17731

I don't know if there's a disc brake version yet, it might be the DH-3D72, but I'm not sure. The older ones are supposed to be significantly less efficient.

Don't forget you can turn last year's knackered/unwanted Tesco torches into mini 3W dynamo lights

Cool. I did similar with a piece of old seatpost and a cheap Cree LED. I keep meaning to make a bottle-cap light* for the front, but I never got round to it as my stock lights are so good- I figure it'd be dead cheap (about eight quid), and would be a very tiny light.

Joe

*two cree LEDs, mounted in two plastic bottle caps with 20mm lenses in (these fit perfectly), with one wired one way, one wired the other, so they are their own rectifier, zip ties to hold them onto the bars / headtube / steerer or somewhere.