Brompton Dynamo Hub

I wasn’t planning on buying a dynamo hub for the Brompton until Autumn. That was until I noticed that the 2011 version of the Shimano hub/wheel is more expensive than the 2010 version (despite being the same). This is most likely due to the fact that Brompton fix the prices of their components to a certain extent, so any price differences generated by things like inflation and currency fluctuations appears as one price hike at the end of the year. For the complete wheel this resulted in an increase from around £68 for the Shimano dynamo hub wheel to around £80. Most sites had already increased their prices, but I found a site I hadn’t used before; Bicycle Magic (Price has since increased here too). It took a bit to dispatch, but otherwise my experience with the new supplier was positive.

I decided that I would run the B&M Lumotec Lyt which was previously attached to the Yuba Mundo with my new hub dynamo; the light will always be on when the bike is moving because it is the un-switched bottle dynamo version, but this won’t be a problem now I know that the drag from hub dynamos is effectively imperceptible even under load. The fact that the light is LED-based means that its operational lifespan is greater than mine, so I don’t have to worry about burning it out. Before autumn I will acquire a new light for the Yuba, or an improved one for the Brompton depending on the state of my finances (I’d love to try a 60 lux Cyo).

The replacement front wheel is functional, the hub isn’t particularly pretty like the polished hub shells from Sturmey-Archer. If you are particularly wealthy, Brompton also offer a SON hub dynamo option (also in super-light, for weight-weenies), which has the advantage of improved efficiency and increased prettiness.

CIMG2425

The wheel fixes into the fork using an allen bolt held in place in a quick-release type configuration. The only benefit I can see in this arrangement is that it is easier to replace than a traditional axle if you accidentally strip the threads. Getting the Brompton tyres off the rim is challenging, but with a combination of brute force and swearing it can be done (Later on the same day I ended up replacing both tyres on both Beatrix and Tallulah Taboo’s Twenties too, making a total of 5 difficult tyre removal/replacements in one evening, I now have quite sore fingers).

The dynamo connections are similar to those used in the Sturmey-Archer hub (X-FDD), although the plug is a more sturdy looking two-piece affair this time. The wire connects to spade connectors on the front lamp, which in turn has spade connectors to power the rear light.

CIMG2429

The bracket of the Lumotec Lyt positions the lamp in such a way that it interferes with the luggage block on the Brompton. I believe there are specialist Brompton brackets for some B&M lights specced by Brompton, such as their basic halogen lamp, or the top-of-the-range IQ Cyo. However, rather than forking out for a new bracket, I decided to gently adjust the existing one with a hammer. It turned out this still didn’t seem to be enough, so I decided to reverse the modified Lyt bracket and bolt it onto the original reflector bracket it replaced:

CIMG2428

The result isn’t tremendously elegant but it works well and doesn’t interfere with the luggage block. The wire to the rear light was run along the front brake cable until it met the cable gatherer, which clips the front and rear brake cables and gear cable (or cables if you have a 6 speed).

CIMG2430

From here I wound the rear light cable along the rear brake cable which ended at an ideal position to connect to the rear light.

CIMG2427

On initial testing the arrangement works perfectly, with the lights coming on even at walking speed. In their current arrangement, the lights will always run when the bike is moving, but I can’t see this being much of a problem really, and may even be advantageous.

Update:

Following a Twitter discussion with As Easy As Riding A Bike, I made a video of the Brompton dynamo wheel (now with several thousand miles under its belt and a shiny Cyo T in place of the Lyt) being spun by hand. The resistance of a dynamo hub wheel when spun like this can be worrying, as it may seem like there is a lot of resistance. However, when backed by the weight of a human rider, this resistance is imperceptible when riding the bike. The dynamo hub definitely provides less resistance than the hub gear pawls do when coasting in third gear (those with an odometer should try coasting downhill on a Brompton or other small-wheeled bike in third and then first gear on a Sturmey Archer three-speed and see the difference).

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13 thoughts on “Brompton Dynamo Hub

  1. Long live dynolighting mounting "hacks!"My Dynotech/Spanninga light combo has been working good this week. Amazing how much an LED will do, just like yours it comes on at walking speed. And having a stand-light is great, too!My only problem so far is that the wire connecting to the hub itself has come loose a couple times, so I need to play around with that.

  2. @Adventure!The "hack" failed on me this morning, the roads of North West England were just too much for it. luckily I had already ordered the official bracket online, which is steel rather than aluminium so shouldn't fail on me in such an immediate manner.How does the VO hub connect to the wires? The Sturmey and Shimano ones I have used use a simple but fairly reliable plastic plug which you feed the wires into.I have had generally very positive dynamo light experiences, I hope use of them spreads.

  3. I've just had the wizzo SON dynamo lighting set fitted to my Brompton, as an upgrade. The battery lights just weren't up to night-time riding in unlit country lanes. I wish I'd gone for this option originally. The SON hub is much smaller (and shinier!) in real life than it looks in the pictures, and it works really well. The lights will come on just wheeling the bike to front gate.The supplied front light is the B&M IQ Cyo, the 40 lux type, with integral reflector and 'near zone' lighting. This is SUPERB – it puts the light just where it is needed and doesn't waste any illuminating the hedgerows. The near zone illumination is particularly useful for pothole- and cowpat-dodging. The lights come on automatically, and the standlights seem to last for ages.The Cyo is 10mm smaller in diameter than the Lyt, and I find it only just clears the bottom of the bag frame. You may find you run into trouble, if using the standard Brompton bracket. You may find you will need a Cyo…Max

  4. @MaxThe Lyt fits under the luggage, but only just. This is probably mostly down to the fact that I have modified the bracket so it sits a bit lower, and that the angle the Lyt is positioned at is not completely perpendicular to the ground. Come autumn however, I will be looking for an excuse to get the Cyo, preferably the 60 lux version too. It should be impressive considering how good the 25 lux Lyt is already.

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