Fog Lights

Have you ever cycled in a dense fog?

For the past couple of days, we have been surrounded by this stunning, surreal landscape. There is no distinction between sky and ocean. The dunes, grasses and rosehip bushes are wrapped in a milky whiteness. There is a tornado warning in effect, but for now everything is eerily calm.

To watch someone approaching through the fog from a distance has always fascinated me.  It looks as if the person is coming from nowhere, or from the sky.

I took the opportunity to see how Graham's lights would perform in these conditions, and they were fairly well visible - even at slow speeds.

The lights on my Rivendell Sam Hillborne are powered by a Shimano Alfine hub.

The headlight is a Busch & Müller Lumotec IQ LED Cyo Senso Plus, and its performance is stunning. The beam is not just powerful, but surprisingly large - so that cycling in the dark feels as if there is always a street light on. There is a standlight feature (the light remains on for a few minutes after the bicycle stops), as well as a "senso" feature, whereby the light turns itself on and off depending on how dark it is.

The tail light is a Busch & Müller 4D-lite Plus, which has classic looks, 4 LEDs, and the same standlight feature as the headlight (though the Co-Habitant thinks the standlight on this one is not sufficiently bright).

An additional feature of this tail light is that it is surrounded by a metal cage, which prevents the light from being damaged when it is bumped. This is very useful when the bicycle is dragged through doors and left at bike racks.

I am confident that others can see me in the fog with the light set-up I have on this bicycle. Seeing the road, however, is another matter. What do randonneurs do in these situations? I cannot imagine that any bicycle light can really be strong enough to act as a true fog light in the daytime.


  1. Good to hear about that light, as I was considering getting it for my Raleigh, the output from the original Dynohub is a bit low for a halogen light, so it doesn't get very bright, and the new light is still way cheaper and much less hassle than rebuilding the wheel with a new hub. I don't usually have to deal with thick fog, but I do ride in the dark a lot, so that will be nice to have.

  2. 2 portlandize- I have the non-4D B&M tail light (more bubble shaped, no protective cage) and the standlight is very bright- barely any difference from the light when pedalling.
    It does tend to get whacked a lot, but so far so good, and they're $30 or so.

  3. Twice I've actually cycled through clouds, both times when descending mountains (once in Vermont, the other time in the French Alps). It was a sort of spatial Zen experinece: I could concentrate only on what was immediately in front of me. Fog offers a bit more field of vision, but is a similar experience, at least for me.

  4. The Co-Habitant might be right ... the 4D-Lite is over 15 years old. :)
    Great photos, as always.

  5. I would love to find a tail light that looks just like the 4D-Lite, only with a brighter standlight. Everything else about it is perfect.

    Justine - I used to live on the border of NH and VT with the same fog-clouds. When I just moved there, the landscape seemed like science fiction, it is amazing there. Cannot imagine cycling in those clouds though, especially down one of the winding mountain roads!

  6. Perfect timing. The dark mornings up north here in Toronto inspired me to buy the same headlamp for my Pashley roadster a week ago.

    I LOVE it.

    I have the "low beam" version, which casts light in the area near to the bike and to about 18m ahead, which is plenty for my needs.

    For a dynamo tail lamp I highly recommend the Toplight Line Plus (rack required!) for it's insane brightness, good side-angle visibility and long standlight performance. (4 minutes +)

    I have been stuck in fog bad enough that the only way to see was to turn OFF my lights (driving from Peterborough (Ontario) to Toronto) - I completely understand the term "pea soup" as a descriptor!!

    I also use a Petzl Myo XP as a back up at times, a great head-mounted spelunking/adventure/etc lamp that I use at work (high-rise electrical construction contracting) - and it helps a lot. Being strapped to your head, the light goes where ever you look.

    I'd love to add HID power supplemental lighting to the Pashley, but just can't justify the cost, weight, or blinding drivers.

    The Cyo IQ was good value for the $. Though I did consider the Schmidt eDelux for the sheer output advantage, I'm quite happy with my light. The Schmidt is just a little too swanky, I think the B&M does the job with a little more discretion.

    FWIW, I used to run a pair of 100W H3s on my VW Cabriolet - the "midnight sun switch", I used to call it... ;)

    Great lights are very important, be it in fog or darkness. Thanks for bringing this up!

    For your entertainment the Big Bang is here:

  7. Gorgeous fog photographs. I haven't ridden in the fog, but I love walking in it.

  8. Was riding down the Tony Knowles trail, a paved bike path in Anchorage a couple weeks ago in a very dense fog that had rolled in off Cook Inlet. Soon after I arrived in Kincaid Park a large moose emerged from the fog in front of me. I was already moving pretty slow so I came to a quick stop and slowly turned my bike around to skidaddle in the opposite direction, but he moved away from the trail and disappeared back into the fog. I could hear him getting farther away in the brush so I was able to get turned around again and continue on my way. I had no lights but, as you say, don't think they would have made any difference in the daytime. Moose are pretty funny looking beasts but when appearing out of fog its like a giant alien being. I'm sure he didn't care for my looks either. I'll admit I was a little scared.

  9. @Bif--I too was on that trail a couple of weeks ago and ran into a very large moose, though fogless. They are very stupid animals that can be aggressive when startled.

    Many randonneurs tend to favor Schmidt hub-generated lights for their output and obvious longevity. Being of very high quality Germanic manufacture, they are priced accordingly.


  10. I have only a little experiance with hub generators but I like the concept. My main complaint was that there was so much drag even when the lights were off(it was an old, basic Shimano model that has a reputation for being "draggy"), I'm told the newer more expensive models are much better in that regard. With the hub you have will the wheel spin for a while if you lift it off the ground and give it a twirl, or does it stop quickly?

    I wonder if anyone makes an alternating current version of a hub dynamo instead of the regular direct current type. If I'm not mistaken with A.C. there would be no drag unless the lights were switched on and then it would only be a little drag as long as you had a little electrical load. It would probably also be $1,000 hub though.


  11. Spindizzy, modern hub dynamos are efficient. The drag is very low when the lights are turned off, and pretty undetectable when the light is on, when you are riding the bike. With the light off turning the dynamo takes about 2.2 watts of power (compared to around 100 watts to ride at 15 mph), turned on the hubs are about 50% efficient, so if your light gets 3 watts you need to put in about 6 watts of pedal power.

    Consider also that Shimano and Schmidt hub dynamos use high-quality bearings otherwise found in expensive Ultrega group hubs; a cheap non-dynamo hub with low-quality bearings may provide just as much resistance after being ridden thru a wet and dirty winter, without the benefit of lights.

    Peter White has the facts:

    I think hub generators are actually AC, but I could be mistaken. LEDs flicker when the wheel is turned very slowly, suggesting alternating current.

  12. Past and current hubs DO generate AC.

    LED lights are their own half-wave rectifiers, and most use full-wave bridges with zeners to limit the voltage (and a cap or two to smooth it out).

    An incandescent bulb doesn't care if the electrons change direction.

    Consider that if you are outputting 200 watts as a cyclist, 3 watts to run your lights is 1.5% of your power - it is noticeable.

    The X-FDD has very little drag, load connected or switched off.

  13. Love these misty atmospheric pictures.

  14. I have the X-FDD on my Pashley. Unfortunately, Pashley uses the 2.4W version instead of 3.0W--they don't run a dynamo tail light and for some reason decided NOT to go with a standard 3.0W hub with a 3.0W bulb. I am sure they didn't even save money doing it, but they've made upgrading difficult. In any case, the stock Pashley headlight is a 2.4W halogen, but I wonder if I can replace it with a modern Lumotec IQ LED + a tail light. Will it work as well as a 3.0W hub that this setup is designed for?

  15. V -- I've only had three rides in low visibility conditions: one foggy beach ride on the eastern coast of the Cape, one midnight journey through a cloudy valley in British Columbia on a 1000k and a weekend century with some fairly thick and heavy rain.

    In all cases. I had a pair of E6s lighting my way and found that they were fine for keeping the road illuminated. The optics of the E6 are such that there's a bit of a blind spot about four feet in front of the bike but everything else past that had good illumination, and the top cut off from the light keeps it from being reflected back up into my eyes.

    Was it as powerful as a car's fog lights? Not really ... but I don't have to travel as fast as a car and don't need to see as far. For a 15 mph average speed, it was fine.

  16. Here in British Columbia the fall fogs have returned to the coast. I have ridden in dense dense fog and cloud many a time. Very eery. Best to have lots of flashing lights. The planet bike flashing lights are very good for that. I have no experience with dynamo hub lighting or any very good lighting for that matter. I have my heart set on a Dinotte 800 or 1200 LED which are supposed to be 'epic' as the kids say and car light bright. I have seen reviews with photos of the lights and they are crazy bright. I do not know if dynamo hub lights get that bright. I do not have experience with battery pack lights either.
    I ride on mostly rural unlit roads. Every winter I say I am going to get a good light, but never have the money and usually curse and cringe my way through the dark with my semi-okay AAA battery lights.
    I love the photos. Yesterday I had to go out early on the bus to the next town and traversed through fog. I walked home through the forest. The sky mingled with brillant sunlight and fog.

  17. I've never cycled in fog, but I think I'd be a bit scared! I've been out at night several times in the rain on streets with very little lighting and it was unnerving due to being so dark. Even though I have lights, I'm going to begin investigating more lighting because I'm paranoid about biking at night - not sure anyone can ever have too much lighting!

  18. I would not cycle in the fog intentionally either, no matter how strong my lights. But if I live in an area like this, I can see how I might get stuck in it on my way home from a long trip. And I agree about never having too much lighting!

  19. MDI - yes - the 2.4W will power the IQ Cyo and a Toplight Line Plus with gusto.

    Most high output light emitting diodes have to run a buck converter circuit to keep the voltage constant, adjusting current to a determined maximum depending on the supply.

    Hubs, conversely, output a waveform that grows in intensity and speed as wheel RPM increases - so the IQ will be changing that increasing voltage into increasing current.

    That's the beauty of highly efficient lights!

    I have full brightness by less than 5kph.

  20. Excellent, I might wire up some sort of tail light into my Pashley. The fender has an ugly reflector where the B&M 4D light would look so good.

  21. I recently installed a 4D-Lite for a city bike project and e-mailed Busch & muller because I though the standlight was defective it was so weak! They agreed it's not as powerful as newer models because it's quite old. In the meantime I'm thinking of updating the internals myself as I love the design and how sturdy it is,. Perfect for a city bike.

  22. If you figure out how to update the 4D, definitely let us know. The standlight is indeed extremely weak.

  23. I am glad to see I am not the only one that feels that the 4D standlight is weak. That is one of the reasons I am using a Planet Bike Superflash as a secondary light.

    @MDI I run the old Sturmey Archer dynohubs, the one I have puts out maybe 1.6 watts, but it will light up a Cyo and a 4D with no problem. I think the 2.4watt Shimano hub was designed for a specific market (German?)It is what I have on my city bike (Redline R530) it powers the IQ Fly and an LED taillight just fine.


  24. @Spindizzy,

    When I put my bike with a Schimdt Dynamo hubbed wheel in my workstand and spin the wheel, I can't detect any drag. If I compare the spin with my rear wheel, I think I can detect a slight difference: when the rear wheel is almost stopped it tends to spin a little longer than the front wheel.

    There is no way anyone could detect the drag in the front wheel while riding. I'm willing to wager $10,000 that if five bikes were set up the same except with a dynamo hub on one bike, the rate of guessing which bike had the dynamo hub would be no greater than 20%, i.e. what you would expect from randomly choosing one of the bikes as the one with the dynamo hub.

  25. The B&M Seculite Plus tailight is a super bright fender mounted tailight, and the brightness of the standlight is as bright as you would ever want. Nevertheless, I couple it with a Planet Bike flasher attached to each rear pannier when touring at night. So on the rear of my bike I have 3 taillights and two big reflective patches(Ortlieb panniers).

  26. ...also I have an IQ CYO Senso Plus (but the nearfield version) attached to the front of a Nitto Mini rack coupled with a Planet Bike headlight($50) attached to the bars that has a flashing mode which mimics the Planet Bike taillights. The PB headlight is so annoying that cars often flash their brights at me. Perfect.

  27. For the fog dilemma maybe constructing a mechanism that sets your lights as close as possible to the road. That way the light illuminates more of the road and less of the fog. Like a light mount that mounts on your fork eyelets.

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