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As just seems to be the case with me at the moment my timing is off - who would be thinking about dynamos and lights on the eve (not literally) of lighter evenings!
I'm curious about getting a dynamo set up to power just a front light.
It would be nice to have a little flexibility as to what it could run on ( fork wise ) and so have been looking at a 15mm set up that I could use a generic adapter for to run on a QR or 12mm fork - I say generic as it is not obvious that you can swap the end caps like on a Hope, DT hub etc ....
6V 3watts appears to be a standard - is this enough to run a decent front light? It would primarily get used on country roads and paths without street lighting.
Any recommendations as to what is good/what is worth avoiding?
Make sure the adapter is compatible with a dynamo, the ends need to be fixed in place so the dynamo's inner axle/winding stays put and doesn't rotate and damage the connector wire.
6V 3watts appears to be a standard – is this enough to run a decent front light?
Certainly, as long as you're not after the equivalent of some 4000 lumen ebay eye burner. For road use I'd look for a good 70-80 lux or higher light with a STvZO beam pattern like the B+M IQ or SON Edelux. Supernova also.
I have an Alpkit hub and a SON in use (plus a SON on the Brompton) in use there's no difference aside from the SON powering up to full a fraction sooner/lower speed. Had a couple of SPs (Exposure) but found the bearings didn't last as well as the 2 I have now (6+ years of good use on the Alpkit hub before I replaced the bearings). The SON lighting's been great for road and gravel use on on both bikes but there are a few options equally good.
Nothing more to add to Jameso really.
B+M IQ-XS is a good light, probably the best bang for your buck on-road anyway.
You can get dummy axles that turn 15mm hubs into QR.
You can get 15mm-12mm sleeves that reduce them to 12mm, but it depends on the fork, they won't work if the fork has any sort of cowl to catch the 12mm end caps. More expensive but there's also a company making reducer axles to run 12mm hubs in 15mm forks. But I'd choose either 12mm or 15mm and stick with it.
I use Shimano dynamos, a nexus on my commuter that lives outdoors 365days a year and an XT on my winter fixie that also does commuting and also lives outside. Neither have been touched maintenance wise.
In theory you can service Shimano, hubs, but it's tricky (there's a thin wire that has to run through a notch in the axle).
SP, SON etc need the hub removing from the wheel sending off to the distributor (IIRC £40 + postage)
6 Vs 1/2 doz but on that basis I'd just buy another Shimano XT and run the risk of DIY servicing the old one at my leisure.
Avoid cheap chinese lamps, I've got one on the commuter and it's adequate, but barely.
Get a decent rear light to go with it (I'd recommend B+M's Secula). The biggest upside to dynamo lights is never having to charge anything, no point going half in.
I wouldn't worry too much about speed Vs power Vs lamps flickering etc. Unless you have a seriously steep hill to get up most setups are at full brightness all the time.
You could also consider the German engineered version of the bottle dynamo https://www.velogical-engineering.com/dynamo/product-information/?lang=en
It generates enough power for my supernova E3 and rear light.
I'm also a long term user of both the Alpkit and XT dynamo and would never go back to charging for utility/everyday use. Don't know anything about end caps/adaptors, but would also echo the advice about going rear light at the same time.
In theory you can service Shimano, hubs, but it’s tricky (there’s a thin wire that has to run through a notch in the axle).
SP, SON etc need the hub removing from the wheel sending off to the distributor
You can do the SP and similar TW-made hubs in the garage but do be careful of that wire sat in the axle groove. It is possible to re-solder them if they get broken by a 'mechanic' who thinks a press fit part is a screw-on part. Don't ask me how I found this out eh. Inc the time to re-lace and build one side of the wheel (tip, leave the non-disc side attached to the rim) I'd say sending them off for new bearings is fair value, I certainly will when the SON needs doing.
What they said!
Don't skimp is what I'd say, I bought the best I could 12 years ago (well SP and B+M) and no regrets, it's so good to know you will always have great lighting and no worries about batteries etc.
Smugness of not blinding oncoming riders/drivers is great too.
I personally find my 100 lux bnm front light good, but not great. Its good enough for riding at night, but its easily overwhelmed by car headlights which can make potholes a bit tougher to manage when there's oncoming traffic. I like the always-on-ness of it, but I'd personally go for one of the brighter front lights if you can (I think they offer something on 300 lux).
Thanks all for the feedback and thoughts.
When running a front and rear light is it just a case of splicing cables together or are there more specific such boxes?
FWIW I have an Exposure (so a rebadged SP) and a Shimano XT. The latter starts to produce sufficient current to power my Revo light with just a couple of spins of the front wheel, whereas the Exposure seems to need a good bit more time.
For a tail light, I have an Exposure that plugs into the front light.
Beware the SP ones badged Exposure (or anything similar) The importers won't touch them. They only deal with hubs that go through the retail set up. Exposure won't touch them either. You can send them away yourself. To Taiwan or similar.
I had a SP and now have a Shimano Alfine. Can't tell the difference although the Alfine is clunky to look at. Also got a Sonder badged thing. No idea what that is. Seems fine as well.
"When running a front and rear light is it just a case of splicing cables together"
Yes, it's that simple.
To add - the Edelux 2 I have on 2 bikes is 100lux at full power, I thought it was a bit less so my comment on 70-80 or more, maybe look for closer to 100 if you can. I haven't found it an issue with oncoming headlight glare but that might be about it being mounted on the fork crown so I see the shadows pretty well. It's not as bright as my MTB battery light (L+M 1400) but it's been good for all but the fastest + tightest roads descents where a wider beam could help on the corners.
I prefer running a battery rear light to a dynamo front. I'll generally want to have my rear light on before a front, and rears in flashing mode tend to run for days or weeks before needing charging/new batteries. Zip tying a cable all the way to the back always bugged me too.
Good thing about a dynamo rear is not needing flashing mode 🙂 or only using one as a back up on a busy/murky/city lights area. Flashers are ok but better alongside a constant I reckon. Plus they're so cheap anyway, in for a hub and headlight, may as well go for the full set up?
When running a front and rear light is it just a case of splicing cables together or are there more specific such boxes?
Varies by light, most front lights have a a regulated 6V AC output either as a couple of spade terminals or some tailing wires to connect to.
You can splice it directly to the dynamo, but the voltage is only nominally 6V at a certain speed. The open circuit voltage is >70V downhill, and rear lights aren't typically protected like fronts tend to be.
The Exposure Revo is easily swapped between bikes if you are swapping the dynamo between bikes std Exposure light bracket. Good standby light as well.
Some brands use a Go Pro type mount for lights, so you can use a Go Pro adapter on an Exposure mounting bracket on each bike. Saves a bit of faff.
I use a Joystick when I know I will definitely be out in the dark , back up on the helmet for slower speeds,and for faster downhill sections and handy for any bike mechanics. Plus a overall back up if the Dynamo wire gets broken or damaged (unlikely but could happen!).
Also handy for seeing the cockpit so to speak.
I point it to the verge if cars are approaching on the road.
As stated above I am not keen on another wire to a rear light so use battery ones on rear.
Rear is rechargeable for commutes and proper batteries for longer adventures and tours .
I like the simplicity of having light at all times and not trying to work out my battery useage. Very useful in the shade on a summers day on the road as well.
Good thing about a dynamo rear is not needing flashing mode
I prefer flashing mode, I feel more obvious.
I have run rear dynamo lights too, I've still got a red eye somewhere - but yeah, battery rears work well for my purposes.
On splicing wires, the rear SON light I have plugs into the front so both are fully current-protected, and the front light switch also operates the rear.
The auto-on mode is nice too, just a light meter switch.
I run rear light off a pair of small heatshrunk flying leads that were already on my B&M front light.
I'm another one that is a fan of a dynamo rear light. It is SO handy having a utility / commuter bike that is always ready to go, and as a driver it is much easier to judge distance if there is a bright but not dazzling fixed light.
Originally I had a mudguard mounted B&M rear light with a stand light feature that was handy but not great quality as the terminals broke after a few years due to vibration (an emergency solder and glue repair at work did last a few months).
A SON rear light was a rather spendy but quality and cute replacement - so nice I made a rack to mount it and the mudguard from 🙂
I have a Nexus front Dynamo hub and I think a B&M front light on a Dutch bike and it’s been rock solid over seven years so far. I wish they hadn’t skimped and fitted a battery rear light on the rear rack though I’ve not bothered replacing it yet either. Dynamo lights are great.
Where you going to be most of your riding, tarmac, off-road of bit of both?
also you also looking ate option to power / charge other devices?
@rootes1 - Mainly road - albeit country roads without street lights. I wouldn't imagine needing to ride off road with this set up.
No immediate need to charge any devices.
The other big advantage of (most) dynamo rear lights is the STVZO ones are built into a reflector.
So as well as the Secula being about as bright as is practically required (it's brighter than an average rear light, but not obnoxious like some rear lights e.g. exposure in their high modes), it really stands out when a car headlight catches it.
No immediate need to charge any devices.
Consider if you're ever going to need this before purchase as some front lights (Edelux II) come with or without the necessary junction box for device charging. The junction box is hard wired to the loom not a plug-in after thought on the EdeluxII.
I’m another one that is a fan of a dynamo rear light. It is SO handy having a utility / commuter bike that is always ready to go, and as a driver it is much easier to judge distance if there is a bright but not dazzling fixed light.
All of ^^this^^ my commuter/winter/pub bike has a guard mounted rear and I have a 2.5mm barrel connector spliced in and positioned under the saddle, my work bag has a second dynamo light on the rear that I can connect/remove quickly, it's so much more convenient to have lights always mounted and never needing charging.
Flashers are a supplementary light, not the main way to be seen, as the brightest thing on you they become a distance reference for drivers, but if they keep blinking that estimation of you distance is potentially going to be affected, add in sleep deprivation and the odds of getting clattered on an overcast morning go up...
"Consider if you’re ever going to need this before purchase as some front lights (Edelux II) come with or without the necessary junction box for device charging. The junction box is hard wired to the loom not a plug-in after thought on the EdeluxII."
Not 100% sure I'm reading this right but fwiw I have an Edelux2 with an external charger (B+M USB-Werk), the charger wire is just spliced into the wire coming off the hub. Can't charge when lights are running as the light pulls most of the current but daytime charging is fine.
New Edelux lights have more options for coaxial connections that look useful though I'm not sure if those connections cover USB out devices.
My EdeluxII has a spare coax out teminal in the middle of the cable that allows the attachement of their USB charging box or anothers if one wants to play silly buggers with splicing cables and plugs. The whole system becomes expensive with charging of phones and gps devices included.
^ I see. A more recent spec than mine. I'd get the line-out and coaxial connecter for the hub end next time round but these lights seem like good square taper BBs on the same bike, a decade or so between purchases.
@rootes1 – Mainly road – albeit country roads without street lights. I wouldn’t imagine needing to ride off road with this set up.
No immediate need to charge any devices.
Only ask as road vs offroad makes a difference in terms of choosing a headlight - the STVZO (B&M, Son, some supernova etc) is that the hard cut off is great for road, but not so great offroad, as the hard cut off does not illuminate low branches etc. (ask me how I know..)
Supanova do a dip/main beam STVZO light which looks like might be good for road and off:
https://supernova-lights.com/en-eu/products/m99-dy-pro
As for charging i used this little box:
https://www.sjscycles.co.uk/dynamos/sinewave-cycles-revolution-usb-dynamo-powered-charging-device/
spliced into the connectors for the hub.
If replacing I might go down the route of using a headlight that has an integrated USB output
Only ask as road vs offroad makes a difference in terms of choosing a headlight – the STVZO (B&M, Son, some supernova etc) is that the hard cut off is great for road, but not so great offroad, as the hard cut off does not illuminate low branches etc. (ask me how I know..)
The other issue, if you're at anything quicker than a pootle, when you lean into a corner the beam points outside even more than a normal bar lamp because of the cut-off. It doesn't feel like an issue on the road, maybe because corners aren't as sharp or frequent, but it makes singletrack difficult.
12x100 axle Son hub after 2x SP hub failures here. Exposure revo front light and red eye rear. Used for audaxes, commuting, touring, off road touring, and no issues. I used the 12mm/qr adapter when I was using it in a qr fork. The lights are on by the time I’ve ridden 30yards to the end of my road.