Introduction

Last winter, I got tired of not being able to see in the dark. In late September, I got caught by the darkness on a distance ride to Ben Lomond. I had to go 20 km with only the fog line visible in my shitty Planet Bike 2*AA Beamer 5 beam to guide me. This was fun, but a bit mickey mouse---I was glad that the pavement I was travelling on was fresh and there were no serious road debris or other hazards to worry about, or it would have been pretty tough going. As well, I moved into a new place that required me to commute every day through an unlit park with fast, twisty roads. When I hit a curb going around a roundabout in this park, that did it for me. I was going to get a good light, dammit.

I did a fair amount of research into different high-powered lighting systems, and concluded that if you want anything that works you are going to have to spend around $300. I settled on the idea of a generator hub and light. I was attracted to the idea of never having to worry about a charge, as high powered batteries tend to drain fast (3-6 hours depending on how powerful your light is) and I am bad at keeping on top of stuff like that. Also, generator lights look hell of rando, and at the time, rando was the new tarck.

After lots of shopping, I got a B&M IQ Cyo with a Shimano model DH-3N71 Ultegra-branded generator hub (the 70, 71 and 72 all seem to be pretty much identical). This combination seemed to offer high performance at a price point well below the next level up (the ultra-blingy Schmidt SON with a Schmidt Edelux light). I've now used this setup through a winter of commuting and several summer distance rides, and it's definitely fulfilled my initial expectations.

The DH-3n71

Shimano's generator hub is terrific, especially since i got it for £40. I got the 32 hole model and built it into an MA-2 rim I also got cheaply (£10!). The total cost of the wheel was around USD $140 after double butted spokes, but other tarckists might not be so lucky.

At 680 grams it's very heavy compared to a regular front hub---the normal Ultegra front hub only weighs around 150 grams. However, for many riders the added 500 mL bottle of pop you will be carrying everywhere won't mean much when you balance it against the convenience of never having to worry about a battery charge.

I thought that drag was going to be an issue, but it hasn't bothered me at all in real-world conditions. Just turning the hub axle you will feel substantial resistance. But the hub smooths itself out at speed, as the resistance is a product of magnets alternately pushing and pulling on the axle, and the push and pull approximately equal each other. An internet tester said that the added resistance with the light on is on the order of having to climb an extra 4-6 feet over the course of a mile. I can't feel any added drag at all when the light is off. There can be noticeable "buzz" or vibration when the light is on, especially when your bearings are a little loose. This has given me some concern when riding around my back alley with the light on in bright sunlight, but it's never bugged me on long rides in the dark.

The hub has good old, user serviceable ball bearings on the non-drive side, with Shimano's excellent borazon races as seen on all their high-end hubs. However, on the driveside where the generator is, the bearings cannot be accessed. I heard it's set up like this because a hub generator is very complicated, and Shimano's engineers don't trust you not to fuck it up. I'm not sure what's on that side as Shimano seems to be pretty cagey about it, but I assume it's some kind of cartridge bearing. If they can't be serviced at all, then the clock is definitely ticking for this hub. Hopefully when the time comes, there will be some way to replace those bearings rather than throw the $80-100 hub away. To be fair, the Schmidt SON's bearings are also not user serviceable; they require that you send it away to a designated service place every 50 000 km or so. But as there does not appear to be a similar service program obviously available for Shimano's hubs, this is definitely something to consider.

You attach the light to the hub via a little male plug in the hub shell just outside the right hand hub bearing locknut. The hub comes with a female plug that you put on the end of your light's wire. You can then unplug the hub when you want to remove the front wheel. This setup works fine and doesn't require soldering to install.

The IQ Cyo

The B&M IQ Cyo is excellent. It cost me £70, but I haven't regretted the purchase at all.

The Cyo has a robust plastic body with a metal top that I think is there to act as a heat sink for the single LED. The big advantage that the LED offers over halogen systems like the Schmidt E6 is long life. People with halogen systems have to carry a spare bulb, just in case, but this is not a worry with LEDs. As a tradeoff, there are riders who prefer a halogen's yellow beam to the blue beam of an LED.

The LED's light is focused and directed by some fancy, engineered reflectors that give you a clearly defined aisle of light to ride in. The reflectors also concentrate the light's power at the top of the beam, where there is more road to be lit up. A light without this feature will light the road right in front of you brilliantly, because it is almost directly facing the beam; but it will leave the road 100" away a lot more dim, because it is not facing the beam anywhere near as directly. These optics are primarily what the high price gets you... there are a lot of cheaper lights that are nominally more powerful, but still don't light up the road as well because they are sending so much of their light up into the night sky, 2" in front of your wheel, and other places where it isn't needed.

The sides of the aisle are a little on the narrow side, so when you're going around very tight corners as in a roundabout, you sometimes won't have light where you'd like it. This is a tradeoff for more riding light in most situations.

The light comes with a fork crown mount but I put it on a scavenged bottle generator mount, halfway up a fork leg. This is working great so far and it's allowed me to use a front rack.

Paired with the Shimano hub, the Cyo is nice and bright at just about every speed. It theoretically gets a little dimmer at very low speeds but since you're going slow, this has never mattered to me in the field. When it's on I can descend at 60-65 km/h in the dark with confidence, but not much faster. It is extremely bright and gets noticed -- it lights up stop signs for blocks, and I can see it reflected off the pale faces of the drivers my bike is pointed at. There is a little capacitor that keeps it on for a minute or so when you're stopped. This is useful to keep car drivers from forgetting about you at intersections.

The Cyo's switch can get clogged with dirt on a muddy, rainy ride, which then dries out and stiffens up the switch's action. To get it clean again, I flush it out with water while working it back and forth. This doesn't appear to impede conductivity or anything, but it's unfortunate all the same. I think it's made much worse by my mounting the light on a fork blade; if it were up on the fork crown tucked behind the fender, it would probably stay a lot cleaner.

Security is an issue with a light like this. It's kind of expensive to leave bolted to your bike, although I don't think it's the kind of thing that casual thieves would be too interested in, unlike e.g. battery lights that attach with a QR. I have a secure lockup area for my regular commute, but I might not want to lock up in the same place every day without something like that. You could certainly fill the allen heads with rubber cement or the like if you were worried, or even try adapting a Pitlock-type system to work. The light itself is held onto the mount with only a single nut, so you could also jury rig a QR system with a wing nut.

Summing up

For the money, these are excellent products and I recommend them to tarck.