Page last changed October 2, 2005

Spotlight on lights

What lights to I need - overviews.

• David Hansen, Oct 1999:
  It rather depends what you do with your bike. A ten minute trip to the station every week, a 75 minute trip every day and needing occasional lights if you stay out longer than expected once a month all have different better solutions. Also important is whether the lights are to be seen in lit areas or to light up a dark lane or path.
  On an L it's probably best to replace the rear reflector with a light with an approved reflector built in. There is also an advantage in using an approved light (as distinct from the reflector). Without one a lawyer may argue that you are negligent in any crash. Seat post lights prevent using a coat that is too long and don't work with the cover bag. LED lights are now good enough on their own to cover just about all uses.
  On the front it really does depend on what you are doing. Personally I use Vistalites. The Road Toad is good for town use and is small to fit in a bag. Fitting on the same bracket I have a VL 400, with external battery pack, for use on dark roads. Which I take depends on the journey. The former has to be removed before folding, the latter can just be spun round. Others mount a small light in place of the front reflector.
  Batteries are variable. For occasional use ordinary batteries don't suffer the self-discharge problems of some rechargeable ones. For more regular use NiCad or NiMh save money and frequent trips to the shops. If you use lights which take ordinary batteries then you can probably buy a get you home set of conventional batteries from somewhere if your NiCads run out of puff. If you have a specialised battery pack you can't do this.
  If you do use rusable batteries put the supplied charger in the glory hole and forget about it. Invest in a smart charger for the types of battery concerned. Sealed Lead Acid batteries need a different charger to others. Ordinary batteries and several types of rechargeable batteries can be recharged in something like the Innovations Battery Manager, provided they are standard sizes. A specialised NiCad battery pack will need a specialised charger.
  I'll add that I also have dynamo lights, these are great as they are always available if I'm later than expected, at the expense of carrying the weight around at all times.

Front light

• Andrew Henry, Sep 1997:
  I use a Busch and Müller Lumotec mounted on the reflector bracket. To fit this you need a bracket with a 90 degree bend in it. The bolt to fit the B&M light needs to be parallel with the axle. I had some of these brackets in my collection of nuts and bolts. Front lights for dynamos normally come with a 2.4W bulb. If you aren't using a rear light, you try to get a 3W halogen bulb fitted when you buy the light. If you can't get this done, the voltage regulator should stop the 2.4W bulb from blowing, but its a bit of a waste.
  The Cyclists' Touring Club mail order shop sells the Nordlicht Dynamo for 17.99 and the B&M Lumotec for 10-12 pounds. They are having a one day sale in a week or two when everything will be available for 20% less. You don't have to be a CTC member to order things from them. The address is Cyclists' Touring Club, 69 Meadrow, Godalming, Surrey, England. GU7 3HS. Tel 01483 417217.
  • David Edge, Nov 1998:
    I like it too, but the rear contact often needs tweaked forward a bit.
• Richard Lighton, Oct 1998:
  [... I] added a moderately reasonable rechargeable light for the front--a NiteRider Trail Rat with a neat lead-acid battery attached to the main tube by yet more Velcro. The bike will fold with the battery in place, but not with the light, even though it is very small. Fortunately it unclips from a handlebar bracket that will allow the bike to fold.
• JP Desbruèhres, Oct 1998:
  For front lights I have been succcessfully using for two years a double CATEYE micro halogen with four rechargeable nickel-metal hybride batteries. Light is very powerful, autonomy more than two hours at full charge and I use one to light the near piece of the road and the other one an extended medium range piece of macadam in the middle of the dark forests of Provence.
  As far as folding is concerned: if you do not tighten two much the screw fixing the mounting bracket on the handle bar, you just turn them 90 degree up to light the stars before folding and this very simple trick does it.
• Andrew Heyting, Oct 1998:
  My solution was to fit a quality LED at the top of the seatpost, and a Vistalite VL 530 on the front. Two headlights wouldn't work, but one on the left of the stem with the battery mounted on the stem up tight to the 'bars works.
  This is technically illegal (light is 10W, and 1" left of centre), but I'm very confident that I can be seen. This set up does not impede folding, either.

Front light and standard pannier conflict

How visible is the light while the bag is fitted?

• David Hansen, Aug 1999:
  Very visible where it is most needed at longer ranges. Try standing in front of the bike and seeing where you can see the light from. Car drivers are lower down than pedestrians.
  A lorry or bus driver is higher up, so is mum on her school run in whatever Land Rovers are now called (but she is looking at little Jemma anyway rather than the road). They can't see it from quite as far away, but even here when it disappears from their view they are about to hit you anyway.
  In crowded traffic the low down light is a problem as motorists may well not see it. Personally I fit a bracket to the handlebars.

Front light lens falls off

• Joel Parks, Aug 1999:
  Oh yes, mine does that frequently when the bag contains my briefcase (~20 lbs?). I doubt it's normal but I can't find anything wrong with the way related parts are installed, so I'm going to rig a safety line on the reflector so I won't loose it on the road. Cyanoacrylate (superglue), stickyback velcro, or some such arrangement.
• Phil Gough, Sep 1997:
  Could try just bending the bracket (or reset, as they prefer in the motor repair trade) assuming it's one of those cantilever jobs. They last about 5 years and snap off eventually but they only cost a few pence.
• Nico J. de Boer, Sep 1998:
  [...] even when simply riding a pretty level road, the front light cover used to separate itself from the bike, at the most inconvenient moments, forcing me to make an emergency stop to grab it away before the wheels of approaching cars. I guess your front light is a "Soubitez" too. However, my girlfriends' front light cover (of the same age) hasn't come off until now, so apparently the quality differs between lights.
  I solved the problem by cutting an "O"-shape out of the thin hard plastic cover of a food container, ca. 2cm diameter with a hole of ca. 1 cm, and a cut through the bottom. Two of those rings between the cover and the "stem" make cover fit really tight. This solution might be a bit more durable than tape.

  |	   ___
  |	  / _ \
  |	 / / \ \
  |	 \ \_/ /
  |	  \_|_/
  

• Rob Cope, Sep 1998:
  Have just checked my front lamp; still haven't bothered removing it despite abandoning dynamos. It has a small hole at the back in the '12 o'clock' position, which matches a socket on the mounting bracket. If you can ease a small screw through both, your problems should be over.
  • Ian R. Platt, Sep 1998:
    Thanx Rob, but I can't see a hole - I see a kind of dimple, but I reckon it is either an extrusion hole for the moulding, ir a reference for you to fit the cover when it comes off!
• Mark Hodson, Aug 1999:
  I find a bit of adhesive tape wrapped around reflector and fitting works wonders.
• Giles Robinson, Aug 1999:
  Also compared my T5 with a friend's. Bag & its bracket near as damnit the same, mine sitting perhaps 2mm lower, due to loose tolerances I guess.

Rear light

• Typical seatpost mounted battery LED lights inhibit folding, unless they are placed right beneath the saddle.
• Mudguard mounted lights are most likely impossible.
• On a pre-2000 T-model's rack (Which model is meant for me? - C or L or T model) a vertical stub pointing backwards holds a Soubtitez light and an L-bracket carries a reflector. There are several opportunities to mount better lights here.
• I replaced light and reflector with a battery powered LED light. Its large reflector fits nicely between the sides of the T5's rack without hitting the ground while folding, and it is not easily detachable (I never lock my T5 outside, so never need to take it off, and I fear a detachable light will fall off one day). I fixed it with two Aluminium 2x20x80mm brackets and holes I drilled in the rack.
• Andrew Henry:
  I have a Vistalite 300X (the old type) on a home made bracket which is bolted onto the loops at the back of the saddle. It would probably get in the way of a big saddle bag, but I haven't tried to fit one. The seat pin can still go down all the way. With the rear light in this position, it could get obscured if you wear a long coat.
• Andrew Henry, Sep 1997:
  The problem with mounting an LED [on an L-model reflector bracket] is that it is obscured a bit by the mudguard. It can also get bashed when you fold the rear wheel under.
• Savi Maharaj:
  I use an LED mounted on the seat post. The post still descends deeply enough to lock the bike when folded. The folded package is an inch or so taller than it would be otherwise, which isn't a problem for me.
• Stein Somers:
  I now realise that since my telescopic seat post descends until it scrapes the ground, it would actually *help* to fit something at the top of the lower telescopic tube. [of course you can also shorten it: Spotlight on the seatpost and saddle - Can one shorten a Brompton seatpost?]
• Custfold, Apr 1998:
  The D Toplicht can fit the rear rack, in place of the existing unit and reflector (the B&M unit has both light & reflector to EU standards). The Front Lumotec Plus is vulnerable due to a weak design of clip on the lens which causes it to fall off in the bag - remedy is to fit extensions to the clamp bolt plates extending forward to grip the sides.
• Mark Lewis, Jun 1998:
  I tinkered with the original lights by replacing the front bulb with a 3 watt halogen. This noticeably increased the brightness of the front light but I wanted then to give this (expensive) bulb some protection from over-voltage. In an attempt to get a better rear light, particularly one which would be bright for slow speeds, I made a 'bulb' to screw into the standard rear fitting consisting of two pairs of hyperbright LEDs and two zener diodes soldered onto a burnt out bulb's screw cap. The zeners stop the dynamo's output voltage from reaching a voltage which will burn out the front bulb. The LEDs have an operating voltage of about 3 volts so two in series gives 6 volts. The nominal output of a bike dynamo! Because the dynamo produces an AC voltage I used two pairs connected in parallel with their polarities reversed to give light from one pair when the voltage is +ve and light from the other pair when the voltage is -ve. There is also the advantage that, even at very slow speeds, the LEDs flash very quickly which makes them appear brighter. I think most of the commercial LED rear lights do this for their steady modes to increase the apparent brightness. This bulb was working very nicely, limiting the voltage for the front light, giving good rear brightness at slow speeds and constant brightness at higher speeds until the dynamo stopped working.
• Jane Thomas, Jun 1998:
  The Busch & Muller rack top 4-D lite fits nicely onto the back of the T- type rack, replacing the existing light and reflector. All you need is a second light bracket, a suitably sized drill, and some courage!
• Roland Elsenberg, Oct 1998:
  The short lifetime of the rear bulb is possibly due to the small whells and the suspension. Imagine that the bulb's wire has to follow the vibrations of the rear wheel on bad surfaces. Due to its position at the end of the carrier/rear triangle it has to travel a longer distance up and down than than the wheel's axle itself. As it does that with the same frequency as the axle, acceleration and therfore force have to be greater.
  Replacing the glowing wire by a LED solves the problem. I replaced the standard rear light by the Seculite Plus by Busch und Müller http://www.bumm.de . Although this is designed for fitting onto mudguards it can be put on a Brompton with a little tinkering. On new Bromptons (At least in Germany) the standard rear light with bulb instead of LED is also supplied by B&M. If you dare to open the Seculite and the ordinary rear light You will see which part of the ordinary You have to use to convert the Seculite into a shape that fits the Brompton. I managed to do this myself, but seem not to be able to explain it in english...
• Custfold, Oct 1998:
  The B&M Lumotec Standlicht (ROUND ONE) will fit in place of the normal one, and the rear D Toplight is almost made for the Brompton - except for the brackets - yes I make an adaptor plate
  With the Standlichts you have the best of both worlds - permanent lighting powered by dynamo.
• Stein Somers, Jan 1999:
  About battery lights: I thought a rear LED light was great: simplicity, full 3W power to the front light, long battery life between recharges, quick to fix and release. Then I started forgetting to switch off the LED light or to recharge it or to take it with me at all. And they are never absolutely waterproof and their plastic fixing wear.
  Now I have a dynamo fed Busch & Müller Toplight (pictured here:)
  It is the brightest rear light I have ever seen on a bicycle, yet consumes just over 40mA, less than half of an ordinary rear light bulb. Its standlight function allows it to work with a slipping dynamo. Fixed solidly to the Brompton. Nothing wears. No bulbs to replace. No batteries to recharge.
• David Hansen, Jan 1999:
  The Cateye [LED light] with five LEDs has worked happily bolted to the rear of my rack for the past 6 months in all weathers and over cobblestones.
• Willi Mindak, Jan 99:
  Yes, the flashing LED's are quite spectacular and equally illegal, at least in Europe. It is unlikely though that you get into trouble with the police because of the flashing (they are happy when you carry a light at all), but you should be aware of it.
  Having said that: last winter I overheard a conversation in a bike shop (I couldn't help it, it was very loud), where a customer complained that he had been fined £ 20 by the police for a working 'cateye' LED rear light (not flashing). The police had told him that it was difficult to see when viewed from an angle, and he asked the shop whether they had sold him an illegal light. After some argument the shop conceded that it was illegal. But you need to encounter an eagle- eyed policeman (which hasn't slept very well the night before) to notice that.
  The B&M Toplight with 'Standlicht' (which Stein wrote about) is bright even when viewed from an angle. It has a little protruding lens to achieve that, and it comes with a German approval (hence: no flashing). So it should be legal in all ECC countries. Is it or is it not legal in the UK? Regardless, I'm quite happy with it and also recommend it highly. I still have to find the policeman to tell me otherwise.
• T.Lawson, Jan 1999:
  Fitting a 5-LED light beside or in place of the reflector on the carrier works quite well until you haul the bike up over concrete steps in way that lets the back end flip under, because then, if you're not careful, the light, with the full weight of the back end behind it, hits the edge of one of the steps and gets smashed to pieces - I write from bitter experience.
• Larry Chinn, Oct 1999:
  I found a small rear Cateye works nicely on the saddle adaptor pin being out the way allowing the seat post to fully collapse. Most light mounts are designed for vertical posts but this one seems to work well with the more horizontal saddle adaptor pin. It's also very small but rather bright.
• John R. Bolt, Nov 1999:
  For a rear flasher mount, I removed the original T5 tail light, and adapted the bracket to carry one of those tiny Cateye flashers. It is so small that I rarely remove it, since thieves are not likely to spot it when the cycle is resting on its luggage rack.
• David Hansen, Jan 2000:
  The Cateye LD-500 (I think its called. The oval one with five LEDs anyway) fits in place of the reflector on a T, if the reflector bracket is moved sideways a bit (just one hole to drill in the rack). It is just scraped on folding, scuffing the top of the cover slightly. Those who are bothered could move it down the bracket a bit. This light has a BS reflector so the legal people shouldn't get upset.
• Jeff Dauvin, Jan 2000:
  I use 2 rear lights - one the same as David & another round one. I have one constant the other on flash.
  If you have a long saddle stem fix the brackets to the top of that as it dosn't go into the frame on folding anyway.
  The way I fitted them is as follows. It only works if you don't have clothing dropping over the back of the saddle but makes reasonably high lights although one does tend to point down it is clear from behind. I needed the saddle higher anyway but didn't want to buy a long stem so moved the saddle to the top of the narrowed stem i.e. high as possible without loosing any of the grip surface. This just makes enough space for a narrow light holder bracket strap to take the top lamp. The other (Cat-Eye) lamp which has a belt clip fitting I fit at the the extreme top of the wide part of the stem. I use a tube bracket with a fitted Velcro strap which my daughter dosn't use for carrying her cable lock. The belt clip fits over the Velcro & I pull it tight so it won't jump off. In fact it is pushed up against top light. The width of the Velcro (c25mm) means the saddle still goes down far enough to lock the rear frame when folded.

Front spotlights

• Jim McLaughlin, Nov 1999:
  I use the Nite Rider "bottle style" lighting system with the Brompton, upright or recumbent versions. The key is the helmet mounting. I found a strap-on water bottle holder that works well on the handle bar stem, although a belt style bottle holder is fine for the upright Brompton. The recumbent Brompton works best if you toss the battery in the pannier on the back of the seat. All configurations need the standard extension cord.
  For skiing I don't usually bother with the flashing red light in back, but on the bike it is essential so be sure to get two helmet mounts. That Nite Rider rear flashing red light is extremely bright. If I have to ride on busy roads in daytime I bring the rear light and it is amazing how much more room I am afforded even by truck drivers. I think it just annoys them so they stay as far away as they can. In daytime I often use the red rear light with the front light off. It is good for some 30 hours in that mode.
  You can special order the Nite Rider with a long cord on the control which is convenient when the light is mounted on your head. Makes it easy to flash people who have their high beams on, etc.
• David Cox, Sep 1997:
  I use a Vistalite VL400 front and an Ever Ready Nightfarer back for regular Birmingham Motown commuting and occasional late night returns from pubs etc. Nightfarer's U2 batteries last for ages with a LED ecobulb (three LEDS manufactured to fit bayonet socket). I use alkaline batteries in summer because they hold a charge over several months and rechargeable batteries in winter - recharging at least every two nights. These are supplemented by Vistalite LEDs (illegally in UK) flashing front and rear. The size of the untrendy N/Every Ready lens helps visibility. I've tried Cateye lights which are bright and very focused but motorists dont seem to see them. Above system requires some forethought but has generally been more reliable than the Sanyo bottom bracket dynamo systems used on my touring bike. These seize up if ridden on local lanes in winter when a corrosive grunge seems to wash off from fields and require regular attention to earthing failures. Brompton is quite slow enough without adding dynamo drag.
• Larry Chinn, Oct 1999:
  For the front light I use a sealed lead Vistalite. The light mounts nicely to the handlebars and I can stow the battery pack in one of the pockets of my front carrier. The only thing I need to remove is the cable when I take of the bag.
  I also have a helmet rear light and third one mounted to my fanny pack but I like to be well lit when riding.
• Jim McLaughlin, Oct 1999:
  On the Brompton I use a Nite Rider Pro 12 with the front and rear lights mounted on my helmet, and with the battery in a water bottle holder on a belt in back. You can't beat having 35 watts available, it doesn't involve bike mounts at all, and having it aim where you look is the best. By aiming with your head it illuminates street signs, gets drivers attention in the city and blinds dogs in the country. Also very good for cross country skiing at night. I special ordered mine with a 3 foot long control cable which is convenient for helmet mounting of the light.
• PHolden960, Nov 1999:
  Nite Rider also has a new NiMH battery about the size of a cig. pack, fairly lite in weight -- 10-12 oz -- (though not in cost) and fits into a pocket.
• John R. Bolt, Nov 1999:
  Apparently like many other Brompton owners, I use a NiteRider front light, with the NiCad battery in one of the back pouches on the front bag. Probably uniquely, though, I attach the headlight (15W Cyclops) to the carrier bag handle. To do this, I machined a slot in a short piece of old handlebar. The handlebar now slips over the carrying handle and is held in place by a couple of small hose clamps. With this arrangement, you remove the light along with the bag--important where I live, since anything removeble left on the bike for much more than a couple of nannoseconds will probably vanish.

Electrical power supplies

Battery power

• Mark James:
  Top tip if you want to use a battery (rechargable of course) torch the Cateye fits and folding is uneffected with torch remaining on bars assuming the handlebars are not tilted back. Battery life with ever ready 1600maH C size batteries (5 £) from Argos about 3 hours. I haven't tested it.
• David Henshaw, Sep 97:
  We run two Bromptons and have used rechargeable lights for the last five years. In that time we've replaced only four batteries and four or five bulbs. Hardly an environmental disaster, and pretty user-friendly too, because we fitted charging plugs to our lights. When you get home in winter, just plug your bike in and the lights are charged by morning. Couldn't be easier. By the way, I would strongly recommend anyone with double 'D' or 'C' cell lights to fit an 0.85 amp, 2.4 volt halogen bulb in place of the Kryptonite or 'made in Hong Kong' standard fitting. They are pretty rare, because they hardly ever fail, but St John Street keep a few. These give a lot more light than the 2 watts you might expect. Infact, set up well, they look as bright as a motorcycle headlamp and actually force oncoming vehicles to dip their lights. Unheard of. And for the REAL environmentalists amongst you, Maplin sell a very neat little 3 volt 80mA solar panel, which should be capable of keeping the lights topped up in reasonably sunny weather - cost about 6 UK pounds. If I didn't always use a Brompton front carrier, I'd fit the panel to the light itself, and recharge as I ride. Or I could always put it on my head. Excellent stuff.
• Dave Horne, Sep 1997:
  I live in the Netherlands and recently bought a recharging device that can be used with ni-cads and *regular (non-chargeable) alkaline batteries.
  To get the most life out of those alkalines, you must 'top them off' after you've used them for a short while ... an hour or two. You really can't 'recharge' them when they're dead. I don't know if these devices are well known or not.
  The cost in Dutch guilders was around 70 which would be about 21 British pounds or 35 US$.
• Andrew Henry, Sep 1997:
  The problem with these lights is that a Brompton doesn't have water bottle cages, and mounting the batteries there would interfere with the folding. Some advantages of dynamos for commuting over rechargeable lights:
  1. They are light enough to leave fitted all year round.
  2. Thieves don't look twice at them. They are bolted to the frame and they have no second hand value. Rechargeable lights tend to be quicker to remove from a bike, and they are more valuable. Fitting and removing lights when you park your bike is a hassle. Rechargeable lights may be heavy to lug around and/or delicate.
  3. A decent dynamo system (ie with a voltage regulator, and good connections) is reliable.
  4. Rechargeable systems might be reliable mechanically. However you then have to remember to charge them up. With the battery chargers which are easy to buy, you also have to remember to stop charging them. If you can't charge the battery where you store your bike, then you have to remember to put it back in place once it has charged. Then when you are riding, you have to remember how long your lights are going to last before they run flat.
  5. 3W is always enough light to see where you are going at 12 mph on any roads around here (Oxford in the UK). 15 mph is safe on most roads. Where there are street lights, then 20 mph is safe. These are minimum speeds. Often higher speeds are also safe.
     To be seen by other road users, 3W also seems enough for me. I am probably more cautious at junctions when its dark, but I don't find I get treated any differently to riding in daylight.
  The main disadvantage with a dynamo is that it slows you down. With a decent bottle dynamo, an average trip speed of 15mph would drop no more than 1mph when the dynamo is switched on. This is a real problem if you are trying to ride at a given pace (eg on a training ride with other cyclists). Besides, riding more more slowly isn't a particularly bad thing when visibility is poor. On my 4.5 mile commute, this means I would take 19.5 minutes instead of 18 minutes at 14 instead of 15mph. How long does it take to fiddle with rechargeable lights: charging them, thinking about charging them, taking them on and off whilst parking your bike, and then carrying them around, even when you might not use them ?
  I guess its a lifestyle choice. I have tried using rechargeable lights but I found it too much hassle each and every day.
• Clive Page, Jan 1998:
  On my old non-folding bike I eventually installed a Ni-Cd rechargable and a tiny rectifier and used the hub dynamo to keep it charged. Worked well, but NiCd batteries don't last long and the memory effect is serious.
  I put a 6v sealed lead-acid battery on my Brompton about 6 years ago. I charge it each night from the mains (you need a constant-voltage charger to avoid damaging them, it is claimed). It all works so well that I removed the rim dynamo. If it every needs replacing I'll consider a Nickel Metal Hydride type, which is lighter and like NiCd but with no memory effect.
  For what it's worth, I recently had to replace a similar sealed lead-acid battery my home alarm system but only when it had been in use for ~15 years. Of course, your mileage may vary, as they say.

Batteries versus original Brompton lights

• Stein Somers, Jan 1999:
  On my recumbent, a pack of 4 D-cells form a permanent power source. The front light and rear light can each independently be powered by that source or by the dynamo with a double pole, 2 way switch. That is not possible if both the dynamo and one of the lights have a mass wired to the frame, which is the case with all dynamo's (even the Axa HR with its separate mass contact), and with both the Brompton's standard lights. (The hinge in the Brompton frame is a bad conductor but not isolated either!) However you can still switch both lights jointly to a battery pack and away from the dynamo with a single pole 2 way switch. I did on an ordinary bicycle long ago. I also rectified the dynamo's AC current and recharged the batteries with that, but I'm not sure how it all worked (in fact it didn't). The obstacle was to separate the batteries from rain and dirt. On the recumbent I got a sealed box from an electronics shop. It and the switches and plugs are well protected from the outside world underneath the seat and luggage. On a Brompton you would have to put everything in a sealed box and find a place for it free of human and folding parts. A plug-and-play unit in the back pocket of the pannier? Where can one find reasonably sized waterproof plug-in connections? How do those remote controlled model boats get their power?

Tyre-side bottle dynamo power

• Andrew Henry, Sep 1997:
  I had to bend the mudguard stay to clear the dynamo. I took half an inch of the wire from the the left hand mudguard side. I then pushed this though to make the right hand stay a little longer so that I could bend it into an S shape using some pliers. There is a picture of this at
  http://www.bath.ac.uk/~bspahh/pics/brompton.gif
  I also had to adjust the handlebars to make them about half an inch more upright or it would bash the dynamo a little when the bike was folded.
  The dynamo fits really well in this position. You can switch it on with a toe flick. When the bike is folded, it is lies between the tyre and the handlebars. [...]
  The advantage of fixing the light and dynamo like this is that you need one 8 inch long piece of wire which you can tape onto the fork. With a rear dynamo, you need two long wires (the front and rear halves of the frame are electrically isolated from each other), and these wires are more vulnerable to getting bashed.
• Custfold, Jul 1997:
  Side tyre types which seem good - Nordlicht (moves straight onto tyre not in an arc), Axa HR (pivots in an arc to tyre, and plastic body has worn out on my one, but others find them OK). Early T types had very cheap Union model, which at the really cheap replacement cost could be regarded as a consumable item like batteries - my 1989 one lasted less than 1 year!
• David Henshaw, Jul 1997:
  The Brompton has been fitted with a number of dynamos over the years. Some were good, but some were downright dreadful, with a tendency to seize unexpectedly, particularly if used regularly in wet weather (not relevant in California). Clearly, a seized, or partially-seized, dynamo will destroy the frail Primo sidewall in a matter of minutes (Spotlight on tyres - How do they cope with tyre-side bottle dynamo's?). We know this is the case because several of you have suffered failures. The latest Axa IQ design seems much better, by the way. We'd recommend fitting the more expensive, but much better, Axa HR, which has a higher efficiency and larger, kinder friction wheel. We all use battery lights here, so our Primos have lasted and lasted and lasted...
• Channell Wasson, Aug 1997:
  I use the Brompton dynamo system with a 2.4 watt halogen bulb in the headlight. The dynamo gives good light front and rear, is always there to use and no baterries to fool with. I find it reliable, quiet and does not give great resistance for around town cycling. The new halogen lighting systems described above give great light, but for convenience at the right price, I like the Brompton dynamo system.
• Custfold, Apr 1998:
  As noted the curly cable from an electric shaver (UK price £4) can be used between front & back lights - I'm looking for a better coiled but light cable. Alternatives are Dynamo front LED battery rear, or 2 dynamos.
• David Edge, May 1998:
  The only dynamos I have owned (out of circa 10) which worked for more than 100 trips were an early AXA-HR which was in daily use so never got the chance to rust solid like all the others (they now have a stainless steel shaft so that shouldn't happen) and the tiny 'disposable' one fitted as original equipment on my three year old Brompton. As it cost about a third of the price of the others, something of a bargain! I've seen something called a Union Turbo which looks like that good old dynamo - is it the same?
• Andrew Henry, Jun 1998:
  I've also got a Union Turbo. Its OK, but it makes a clicking sound, like something inside is sparking. The spring mechanism is a bit weaker than on a Nordlicht and it sometimes switches on when you hit a big bump in the road. I don't think Union Turbos have ever been fitted to Bromptons as new. They have a brushed grey aluminium body. The wheel is rubber with a thin serrated metal bit in the middle.
• Roland Elsenberg, Aug 2000:
  The new and cheap AXA Caluna runs smooth and is light: 112 g.
• Riding issues - Silencing a whiny generator
• Roland Elsenberg, Sep 2001:
  I tried the AXA HR, AXA Caluna, Nordlicht, AXA iQ (Standard OEM), Busch und Müller D6 and Union Turbo.

  AXA HR:

  Good and long lasting on my Gazelle, but too heavy. Tends to break the Bromptons dynamo bracket at the point where the cable runs through. Activates itself due to rapid up/down movement of the rear triangle. When the AXA HR's own bracket broke out of it's plastic moulding I gave up.

  AXA Caluna:

  Not half as heavy as it looks. Activation unaffected by up/down movement. Broke internally after less than 1 year.

  Nordlicht:

  Good and undestroyable. Get one with rubber ring instead of metal only wheel. Activation mechanism completly unaffected by up/down movement. Very heavy. Broke Brompton bracket as AXA HR. Since reinforcing the bracket it works fine on my black Brompton. Swap the original rubber ring for a tyre from model car to get it going in the wet or snow if need be.

  AXA iQ

  Does it's job for about 1-2 years of daily use and leaves the Brompton bracket intact. Cheap.

  Busch und Müller D6

  Do not confuse with the much more expensive S6 model. Adjustable spring. Slips in the wet even at max pressure. Heavy. Broke it's *own* bracket and destroyed two spokes of my red Brompton. Got money back.

  Union Turbo

  Very light ;) 99g. Does it's job on my red B. Not really quiet. Gets hot but seems to be unaffected by that.

  If you go for a heavy dynamo check the mounting bracket regularly. Since they are from steel they tend to break slowly.

Axa IQ

• Jane Thomas:
  In fact the new T5 we got a few weeks ago has an Axa IQ - it's smaller and lighter than the HR. I know Brompton have had a lot of problems with their dynamos - I would try to get it exchanged, as the IQ does seem much better - it works well, and dosn't have that annoying habit of turning itself on. The gears broke after about 5 miles, but that's another story....
• Stein Somers, Jul 1997:
  According to a Dutch ANWB test, the IQ has 5% less drag than the HR. It is also less efficient, but still quite good. If one adds a standard rubber dynamo cap, or a homebrew like Channell did, then it should slip less than a HR (I don't suppose there's a dynamo cap for HR's). Installing a battery powered LED tail light then leaves enough power for the headlight. I think this is the ideal lighting setup: no need to worry about recharging; when one bulb blows, no danger of overloading the other one; rear light when you're standing still; and the environmental impact of a pair of batteries might well be less than the electronics involved in providing the same functionality based solely on dynamo power.
• Mike Paley in Millom, Aug 2000:
  AXA IQ 1 failed in 1 month - felt like the bits that shouldn't go round, did. I suspect something came loose during a fold/unfold operation.
  No.2 was a bike shop temporary replacement while No.3 was supposed to arrive. No.2 was too stiff to work reliably in the wet.
  No.3 is still going strong after a year. I got it from Brompton direct as the bike shop are pathetic.
  The punchline was that I was told that the dynamo was only for light use. Err, I only use it for the lights ?! :)
  BTW, after detecting stiffness in the operation of the on/off action, it got oiled. It has now bounced OFF once and ON 3 times. I think 100 psi in the tyres has something to do with that :)

Axa HR

• Stein Somers:
  Just spotted the second issue of a yearly Dutch cycling magazine called "Fietsen '97". In a dynamo test, the Axa HR clearly wins from 6 "tyre-side" dynamos. Best headlight is Union 9430 (almost 10% more light than Axa Hilight. They list measurements in lux but don't specify where they measured it). Best dynamo powered tail light is Axa Optica 3 or Soubitez Combilight. If you want the tail light to shine on during a stop, without requiring batteries, Axa Optica 1 is the light to choose.
• Martin Whitfield, Jun 98:
  I have found the lights to be not bad in terms of power, particularly at the front. I have switched the back unit to an AXA HR which gives a great deal better peformance and fits on the bracket perfectly. Others have warned that the bracket can snap with the extra strain, but mine has survived one winter ok so far.
• Meryl Prestidge:
  I fitted an Axa, having used one on my commuter bike, and it works very well even in pouring rain. However, it's slightly longer than the original and can't be adjusted to the correct angle (radial to the wheel). [...]
• Stein Somers, Jan 1998:
  I just slaughtered my Axa HR. The dynamo bracket fits in slots in the plastic case and is only retained by a metal thingy serving as earth contact as well. In my case, the thingie failed to convince in both roles. Unlike other bottle dynamo's the fixed magnet rotor surrounds the coil. If anyone doubted, it is definitely equipped with a pair of 7V5 Zener diodes. By the way there is a new model out with a more bottle-like shape. A local bike shop manager said the Nordlight isn't better.

Nordlicht dynamo

• Andrew Henry, Sep 1997:
  I use a Nordlicht 2000 dynamo. It is just the right size to bolt onto the mudguard stay bracket on the right hand fork blade. Other types of dynamo might also fit, although you need one which faces backwards when you bolt it on the right hand fork blade. [...]
  I had to bend the mudguard stay to clear the dynamo. I took half an inch of the wire from the the left hand mudguard side. I then pushed this though to make the right hand stay a little longer so that I could bend it into an S shape using some pliers. There is a picture of this at http://www.bath.ac.uk/~bspahh/pics/brompton.gif
  I also had to adjust the handlebars to make them about half an inch more upright or it would bash the dynamo a little when the bike was folded.
  The dynamo fits really well in this position. You can switch it on with a toe flick. When the bike is folded, it is lies between the tyre and the handlebars.
• Custfold:
  One caveat is that the nordlicht should have a larger bolt than that which normally fits the L series hole, and the claearance and 'tit slot' needed to properly mount the Nordlicht are not there. Ideally some delicate work with a rat tail file, and small flat (warding) file can make the necessary adjustments.
• Custfold, Apr 1998:
  I use the Nordlicht dynamo with rubber wheel running on the rim - very few problems, put the brakes on and the water is squeegeed off. As a reserve the lights are also B&M Standlichts so even if there is a momentary slippage the rear stays on (slightly dimmed, and the front flicks over to the very bright yellow LED which looks not unlike a dim battery lamp, but aided in the oncoming headlights by the bezel which is a clear reflector around the lens.
  The Nordlicht dynamo has a couple of nice design features - it has a tit which will locate in a notch cut in the mounting bracket - thus locating it positively rather than relying on the bolt being locked really tight. Then the dnamo rotates on an axis parellel to the rim making the pressure independent of the direction of wheel rotation - unlike the AXA and Union models which rotate around an axis at 90 degrees to the wheel movement, and potentially dragged in in one direction or pushed out in the other.
  THe alignmant of the dynamo wheel/roller is very critical for best performance - and the rigidity of the Brompton mounting is limited (you can bend it by hand), and the rack can also be affected by movement relative to the rear frame.
• Stein Somers, May 1998:
  Another great difference with the Axa HR is the sound: the Nordlight is truly unnoticeable at high speed. Below 10 mph it starts vibrating in resonance with the T5's rack.
• David Edge, May 1998:
  I have had three Nordlichts: the first broke the shaft after six months the second vibrates hideously; I moved it to a cumbersome where it does the same, but there is less resonance the third sometimes applies with great force, sometimes with little. If you bend the bracket close enough to the wheel for it to work in low force mode, you get high drag in high-force mode.
• Andrew Henry, Jun 1998:
  I've got three Nordlichts and I've never had any problems with them. Two haven't been used much, but I've done a thousand miles or so using the other.
• Norman Tulloch, Oct 1998:
  I bought the Nordlicht from the Cyclists' Touring Club shop via mail order a couple of years ago. So far as I can recall, the CTC also sent me a sheet on setting up a dynamo by Chris Juden, the CTC technical superperson. I took quite a bit of trouble to line the dynamo up properly and to try to get the dynamo-tyre distance right, but, while the dynamo is just fine in the dry, it certainly isn't in the wet.
• Willi Mindak, Nov 98:
  On my T5 the original dynamo bracket was too high to allow the Nordlicht 2000 to run against the rim. It was either to be run against the tyre sidewall, or a homemade bracket had to be made. I decided to run it on the Primo, and had no problem so far (but I only did a around 200 Km with this setup). Sidewall wear doesn't seem to be the problem with the Nordlichts rubber ring, but I'm getting slippage in the wet. It hasn't fallen off yet.
• David Edge, Nov 1998:
  I removed one Nordlicht which was slipping and bolted another in the same position which didn't. A manufacturing quality problem I fear.
• Stein Somers, Nov 1998:
  I have two of both models and not the slightest doubt that the Nordlicht is mechanically stronger, makes much less noise, and its engagement mechanism is more suited for a Brompton. Maybe the Axa is more efficient, and its built-in voltage regulator is definititely an advantage, but it's not good for a Brompton.

Busch & Müller Dymotec S6

• Peter Amey, Sep 1999:
  There seem to be two main contenders in the high-efficiency bottle dynamo market. There is one from Busch and Müller, the Dymotec S6, which claims 60% efficiency. They are about UKP 75. This dyno also has a interesting option of a roller in the form of a sort of wire brush which is supposed to be both very slip resistant and sidewall friendly - might be good with Primos but I haven't tried one.
  The second, which everyone is talking about at the moment, is the [Spotlight on lights - LightSpin]
• Olaf Schultz, Sep 1999:
  [60%] AFAIR only at 15 km/h, at higher speed worse (nearly 30% at 30 km/h). Efficiency-measurments are available on http://experte.kt2.tu-harburg.de/
  Don't use [the wire brush] on skinwalls. Some wires are 0.5--1mm higher than the others and perforate the tire and the tube. And it is no help to cut all these wires, because with the time other wires come out and cause trouble.
• Roland Elsenberg, Jul 2000:
  My Busch & Müller is no improvement [with respect to slipping in thhe rain]
• Roland Elsenberg, Jul 2000:
  Today the Busch&Müller dynamo broke off and got into the rear wheel. It tore 2 nipples apart, wound the spokes round the hub and cut a deep scratch into the rim. This time the failure was not in the bracket on the carrier stay, but in the dynamo itself. This dynamo was considered to be a quality product, with all sort of signs and labels on it. B&M know how heavy their dynamo is. Is it so difficult to estimate the vibra tions it has to withstand and to determine how strong the bracket should be?
• rnh17, Sep 2002:
  My original Axa failed after about a year, and I replaced it with a B&M Dymotec 6. The wires don't attach well (it uses plug connectors which don't lock in place), and the roller seemed to go from the off to the on position with every bounce, so I have to position it against the mud guard when not in use. But it does seem more efficient than the Axa.
• Ian (two Bromptons) Oliver, Sep 2002:
  Yep, I found all of that. And it kept bouncing into the "off" position when I really didn't want it to.
  I also found that unless I used the "wire brush" roller it didn't make contact and that the wire one wore a hole in the side of a tyre in only six weeks.
• Ian Fleming, Aug 2003:
  I have used the B&M S6 with wire brush roler for 2 years with no problems on my 15 year old T3, mounts on original rear rack fine, the roller just clears the mudguard. I have replaced the Schwalbe Marathon tyre once or twice in this period, and they did show significant side wall wear, but the dynamo never slips.

LightSpin

• Olaf Schultz, Sep 1999:
  At the moment there are the Dynosys LightSpin's (http://www.dynosys-ag.ch) in several tests. Espacially the CTC has some in practical use (Just ask Chris Juden). I see the problem in unsealed ball bearings, the first rainy winter will show it:=)
• Peter Amey, Sep 1999:
  [...] the LightSpin from Switzerland at about UKP 45 (more if you want a backup battery built in); this claims astonishing performance levels. Someone at the CTC told me you could spin the roller with your fingers and it kept spinning for a while, unlike all the dynos I have seen which stop instantly when you let go. The CTC shop are going to stock the LightSpin. The main problem here is that there seems to be a degree of vapourware about the product. The CTC shop have been expecting them for months and I was promised one for review at the beginning of August and have not seen it yet.

Rim-side bottle dynamo

• Peter Amey, Jan 1998:
  I run a Nordlicht dynamo on the rim because I found it damaged Pr1mo tyre walls. It is mostly ok but does slip when its very wet (mind you it used to slip in the wet on the tyre wall as well). One advantage seems to be that you can start it spinning again by putting the back brake on which clears water from the rim.
• davidh, Jan 1999:
  However, I have had a Nordlicht dynamo running on the (front) rim since Folder Forum. This avoids any wear on the tyre. The dynamo runs very smoothly. In very heavy rain it will slip, but it is better than the Brompton dynamo on the tyre in this respect which used to slip in medium rain. With the Nordlicht a gentle pressure on the front brake clears enough water to keep it running, without slowing me down.
• Peter Amey, Jan 1999:
  Alignment is important: I used a perforated steel strip (like "Meccano") to move the dynamo mount down and to the right of the fixed bracket. The fix is not perfect - it still slips in greasy/damp conditions (but seems ok in torrential rain?!?) but an application of the brakes usually brings the lights back on. I am also confident that I am not trashing any more expensive Primos.
• Custfold, Jan 1999:
  I use the Nordlicht running on the rim with its rubber wheel - relatively successfully, although in recent weather the combination of road grime and water has let the thing slip when I'm riding fast, but it regrips when riding slowly.

Bottom bracket dynamo

• Lui, Aug 1997:
  I use the Soubitez contacting the full tyre from above. Theres metal on their rollers, but I used a small bit of an old tyre over the metal glued. Worked one complete winter including snow, rain. Its of course not the best way on small tyres, I use it this way on the 26" rearwheel from my bent.
• David Cox, Jan 1998:
  Bottom bracket dynamos by Sanyo, Union and some French manufacturer were popular on touring and audax bikes for a while. I had several years out of one but others would slip in the wet (leading to all sorts of superglued innovations with Flymo drive belts) or seize up after getting full of grunge washed off local fields. The position is very vulnerable to road crud and spray. Audax riders seem to have moved to high efficiency sidewall driven bottle dynamos like the AXA and the Nordlicht sold and recommended by the CTC. The Sanyo was nicely made but would not fit a Brompton in the standard place. I wouldn't bother.
• I head a witness who put all his hope in them but gave up. They're fine on clean roads, but mess up in the least of dirt.

Hub dynamo (BromSON)

• Roger Smith:
  You can't beat a Sturmey Archer front dyno hub built into a 16" front wheel. The drag of the hub is negligible, swapping from a standard front wheel to a dynohub I could not tell it was there. You can only really feel the drag if you try to rotate the wheel by hand. The hub is totally silent.
  Roger Smith:
  Raleigh actually marketed their RSW with a dynohub as part of the factory fitted equipment; this bike has smaller diameter wheels than a Brompton (16" x 1.75 actual diameter about 15 inches 375 mm).
• Custfold, Jul 1997:
  Juliane Neuss has fitted a Wing dynohub in front wheel, with 'widened' forks.
  I have some old chrome plated Miller units, and Indian copies in the bits box which I covet ferrociously.
• Lui, Aug 1997:
  I prefer hubdynamos (frontwheel) like the Renak Enparlite (there is a version for 16", too) and it worked for me in citytraffic and excessive night riding, too. The added effort is that small I often used it at daylight without feeling it. [...]
  The Renak Enparlite is a german product and I got mine via mailorder from bicycles, a German mailorder company. Their web is http://www.bicycles.de . The Renak has internal gearing in the hub, it's small - looks like a normal hub. Different versions have different internal gearing fitting your wheelsize. The price from bicycles is around DM 150,- [...]
  I know some other hubdynamos (one of my favorits is a a great british product,the Sturmey Archer 3 speedhub with dynamo I have now for 30 years on my "classic Moulton" but someone told me its not in production for some years now(?) Most others I know like Sanyo, Union, Wing aren't well suited for small wheels.
• Andrew Henry, Sep 1997:
  [...] use a Schmidt dynamo. These are made buy the guy who designed the Union Wing dynamo. He makes a version which is designed for 20 inch recumbant wheels, but I'm sure that they would be fine for use with a Brompton. They cost 290DM (about 100 pounds). The downside is that you have to order them from Germany, and paying for them can be a bit of a pain as few German companies take credit cards. You could pay by Eurocheque, which your bank would charge you for. Another alternative is to get to an American Express office where they can give you a cheque in DM for a couple of pounds commission. In any case, address to contact is:

  Wilfried Schmidt Maschinenbau Aixer Strasse 27 72072 Tuebingen Germany Tel: +49 7071-38870 Fax: +49 7071-38876

• John Blackburn, Jan 1998:
  A few notes that may help to illuminate the subject of dynamos.
  1. Tungsten tempco Pure metals have a resistance that increases by about 40% for every 100 degrees C rise in temperature. This is true of a tungsten filament in a cycle bulb; if it were not true, bulbs would "blow" more often. The bulb runs at over 1000 degrees C, so this is a very significant effect. When cold, the resistance of the filament is very low. If a voltage is connected to the bulb, a very large current flows. As the bulb heats, the resistance increases rapidly, cutting the current down and finally reaching equilibrium. This "self-regulation" effect is useful, but is not enough to protect bulbs from extreme over-voltage.
  2. British Standard BS6102/3 This deals with cycle lighting, and has a section on dynamos. It calls for a degree of regulation in the dynamo itself:

     Speed km/h		Volts as percentage of rated output
     MIN	MAX
     5	50%	117%
     15	85%	117%
     30	95%	117%

     So, the dynamo must not produce more than 117% of its rated output under any circumstances. For example, a 6 volt dynamo must not produce more than 6 x 1.17 = 7.02 volts.
     BS6102/3 was produced in 1986, and looks a bit obsolete. LEDs are not mentioned. But it is still a good guide, although it should be noted that "BS6102/3" printed or stamped on a cycle lamp means only that the maker claims that it meets the Standard. The BS "kitemark" logo guarantees compliance. If there is a more modern DIN, ISO or US standard I would like to know about it.
     • {Richard Pearson, Jan 1998} I believe there is now a revised version of BS6102/3 which allows LEDs, at least at the rear. I have a BS marked rear light which is a large LED (non flashing) recently purchased from Halfords.
     
     So if a dynamo - or a Raleigh Dynohub - meets this Standard, it must contains a regulator of some sort. The cheapest way is to use a controlled amount of iron in the "magnetic" part of the dynamo, and ensure that the correct bulb is used. As you cycle faster, the voltage output increases, so the current through the bulb increases (but not as much as you expect, due to the "tempco" effect already mentioned). This current is, of course, the current produced by (and flowing through) the coils in the dynamo. At high currents, the iron on which these coils are wound becomes magnetised so strongly that it "saturates" - it can produce no more current, no matter how fast you go. It saturates twice on each revolution of the dynamo.
     This crude system has been used for decades. Note that it limits the CURRENT, not the voltage. If you fit a bulb with a higher resistance (that is, one intended for a higher voltage), you may find that it blows more easily; this is the opposite to the situation if the voltage were regulated. It is not an easy thing to analyse.
     If a Raleigh Dynohub from a 20-inch wheel is fitted to a 16-inch wheel, it will revolve faster, but if it complies with BS6102/3 then it probably contains a regulation system as described above, and it would work satisfactorily. But it must be remembered that magnetising iron to saturation and then reversing it (as happens on each revolution) requires a good deal of energy (which heats the iron), and the energy all comes from pedalling.
  3. Zeners Putting two Zener diodes (in series) across a dynamo will certainly regulate the voltage, by "chopping the peaks off" the voltage sinewave produced by the dynamo. It is, however, from an engineer's point of view, a really stupid way to do it, because the excess energy that is shunted through the Zener diodes all comes from extra pedal effort. Suppose, if the voltage exceeded 6 volts, an excess current of 1 ampere was shunted through the diodes. This is 6 watts wasted in heating Zener diodes! And the bulb is only producing 3 watts! The appeal of this system is that it is really cheap to fit. After all, an unscrupulous maker might say, it's only a BIKE...
  4. Other systems. A "series voltage regulator" would regulate the voltage but has two disadvantages. The first is that the excess voltage is wasted in heating the regulator. For example, if a 9-volt dynamo output is reduced to 6 volts by the regulator, and the current is 1 amp, then the power wasted in the regulator is 3 watts, because the excess voltage is 3 volts which, if multiplied by the current, gives the watts dissipated in the regulator. The second problem is that a series regulator requires a DC supply, whereas a generator produces AC. The AC can be rectified with diodes but at least 1 volt is lost in the diodes, which is a significant loss in low-voltage systems. It starts to get complicated and expensive.
     Much more sensible is a PWM or "pulse width modulator" approach, which uses a "Power VFET" (a kind of large transistor) to switch the bulb on and off at a high rate, fast enough to avoid flicker. The on/off time-ratio is automatically adjusted to control the power reaching the bulb. There would be almost no power loss.
     A visit to a bike shop shows that batteries make much more sense to most users. Cycle lamps are much improved and are now fashion items. Dynamos are not popular. I have, however, always found dynamos to be reliable; they never fell off, or went wrong, or rattled or slipped - not for me. Some other users, of course, have other experiences; maybe they are unlucky, or careless, or lack mechanical skills.
     On my Brompton, I intend to move the front lamp to the top of the handlebars (where it's handy for looking at maps, etc), and fit a 6-volt rechargeable lead-acid battery, which has a very stable voltage and needs no regulator. I may keep the dynamo as an emergency charger. Or I may fit a small "trickle-charge" generator, or even a solar cell. I'm not sure yet.
• Custfold, Feb 1999:
  A rear hub version of the Dynohub was made - and can be found combined with (usually) an AW3 hub, but IIRC this is a 130mm axle 36 hole unit only ... but prove me wrong folks. A 28 hole 112mm axle would fit the brompton but the spokes....!
• Olaf Schultz, Sep 1999:
  Schmidt, a german Dyno-hub manufactor will made three prototypes of the BronSON, ready for the IFMA (Cologne) at the end of September. The use the old fashioned hub, not the new (complete alloy, small diameter) for the 20''-wheels.
  For detailed measurements and background: Look at http://experte.kt2.tu-harburg.de/fahrrad.html (sorry only in german). Attention: The HTML-Version has severals failures in tables, the PostScript-Version is right.
• Olaf Schultz, Sep 1999:
  The main problem is the width of the axis. So there are two possibiblities:
  • Take another fork (like Juliane Neuss from Germany, the Inventorness? of the Brompton REcumbent Conversion KIt) She took a Renak Enparlite, bridged one of the three gears and use it at her Brompton. Than you can use a normal 20''-SON and use it perhaps from 10km/h (or less) up all time with two normal 6V/2.4W Headlamps in series. She also fixed Magura Hydraulik Brakes at her new fork: Once she had to brake hard, the tail went up and the rear wheel folded nearly:)
  • Or wait a little bit for the BronSON. The first three Prototypes should be ready for the ifma (Cologne, Germany) at end of September. The protoypes use the flanges of the old Version with a smaller steel-ring betewenn them (Width-Diameter-Ratio like a Hub-motor, not Hub-Generator:=)
• Roland Elsenberg, Sep 1999:
  Today the IFMA was open for the public. Until last year IFMA ment Internationale Fahrrad und Motorrad Ausstellung. This year motorcyclists have their own fair, so the abbreviation is explained as Internationaler Fahrrad MArkt. This markets speciality is that nothing is sold to the customer (dealers only) [...] I have seen a hub-dynamo in a Brompton with standard fork (70 mm). It was handmade by Andreas Oehler, who works for Schmidt-Orginal-Nabendynamo SON. There was a list where potential buyers could sign and state they are interested in a small series. The price is targeted around 400 DM. It is a clever device without internal gearing and therefore has high efficiency.
  I mailed Andreas Oehler wheter he aggrees that his adress is made public on this list. My point was that there could be bromptonites who had no possibility of stating their interest for his dynamo by signing his list on the IFMA in cologne. Those should mail to him Andreas.Oehler@gmx.de . He says interest in his dynamo was surprisingly high. He would prefer selling directly to the customer since he sees no margins for distributers or dealers if the price should be a reasonable 400 DM with halogen front light (B&M lumotec with switch)
  He had a leaflet on the IFMA. If there is interest, I'll try to translate later although translating in the other way from English to German is so much easier... This was its text:

  an alle InteressentInnen einer robusten
  Dynamo-Lichtanlage für das Brompton
  
  27. September 1999
  
  bromSON: der schmale, leichte, getriebelose Nabendynamo für die 70mm-Gabel
  
  Dynamos an Falträdern führen häufig zu Ärger: Ihre exponierte Lage läßt sie
  oft unbeabsichtigt verstellen oder führt zum Kabelabriß - abgesehen von den
  gewohnten Traktionsproblemen des Reibrades bei Nässe... Am Brompton-Faltrad
  ist die Montage eines Dynamos außerdem nur bei Verwendung des ansonsten
  kaum
  nutzbaren Gepäckträgers möglich.
  Gerade an Falträdern wären deshalb robuste Nabendynamos ideal. Leider waren
  diese bisher aber nur für Gabeln mit 100mm Weite erhältlich, was den
  aufwendigen und nicht unproblematischen Austausch der Gabel erfordern
  würde.
  Meine Erfahrung als Angestellter der Firma Schmidt Maschinenbau ermöglichte
  es mir, den bewährten SON Nabendynamo so zu modifizieren, daß er ohne
  Änderungen am Brompton montiert werden kann. Dieser bromSON unterscheidet
  sich vom alt bekannten SON hauptsächlich in der verringerten Breite der
  Achse
  und des Magnetrotors. Durch diese Maßnahmen konnte das Gewicht auf
  erfreuliche 450g gesenkt werden. Das gesamte Rad wird somit 50g leichter
  als
  ein mit einem Nordlicht Dynamo bestücktes Brompton. Die an einer 6V3W
  Lichtanlage erzeugte Spannung entspricht den Vorgaben der StVZO. Der
  erreichte Wirkungsgrad liegt bei etwa 55%.
  Der bromSON kann radial mit 28 130mm Speichen oder 2-fach gekreuzt mit den
  im
  Original-Vorderrad verbauten 150mm Speichen eingespeicht werden.
  Geschaltet wird der bromSON wie der SON an einem Lumotec mit integriertem
  Kippschalter am Gabelkopf. Wer auf ein Dynamo-Rücklicht verzichten mag,
  kann
  hier eine 6V3W-Halogenlampe verwenden.
  
  Die Modifikation des SON bedarf einiger Handarbeit und dürfte bei
  Produktion
  in nennenswerter Stückzahl einen Mehrpreis von mindestens 80DM erfordern.
  Sinnvoll könnte das Angebot komplett eingespeichter Laufräder zum schnellen
  Austausch sein, was mit weiteren 100DM zu Buche schlagen muß.
  
  Um überhaupt das Interesse für das Produkt abschätzen zu können, würde ich
  mich über  entsprechende Rückmeldungen freuen.
  
  Mit freundlichen Grüßen
  
  Andreas Oehler
  

• Mark Hodson, Sep 1999:
  Quick translation, with the help of BabelFish - I think I've removed enough howlers for intelligibility.

  To all prospective customers for a durable Dynamo lighting system for the
  Brompton
  
  
  27. September 1999
  
  
  bromSON: the narrow, light, gearless hub direct current generator for the
  70mm-fork Dynamos on folding bikes lead frequently to annoyance: Their
  exposed position lets it adjust often unintentionally or leads to cable
  damage - apart from the usual traction problems of the friction wheel on wet
  roads... On  the Brompton the assembly of a direct current generator is
  additionally only possible by using the otherwise almost useless carrier.
  Especially on folding bikes durable hub direct current generators would
  therefore be ideal. Unfortunately they were available so far however only
  for forks with 100mm width, which would require the expensive and not
  unproblematic exchange of the fork. My experience as an employee of the
  company Schmidt mechanical engineering enabled me to modify the proven SON
  hub direct current generator in such a way that he can be installed without
  modifications to the Brompton. This bromSON differs from the old well-known
  SON  mainly in the reduced width the axle and the magnet rotor. The weight
  could be lowered by these measures by a satisfying 450g. The entire bike
  becomes thus 50g lighter than a Brompton equipped with a Nordlicht direct
  current generator. The voltage produced at a 6V3W lighting system
  corresponds to the specifications of the StVZO. The achieved efficiency is
  approximately 55%. BromSON can be  spoked radially with 28 130mm spokes or
  two-way crossed with the 150mm spokes blocked in the original front wheel.
  One switches bromSON like the SON at a Lumotec with integrated rocker switch
  at the yoke. Who may do without a direct current generator taillight, a
  6V3W-Halogen lamp can use here. The modification of the SON requires some
  manual work and might require an additional price of at least 80DM with
  production in considerable number of items. The supply of completely  spoked
  wheels for fast exchange, would be sensible, which would cost a further
  100DM . In order to be able to measure at all the interest in the product, I
  would be pleased about appropriate responses.
  
  
  With friendly greetings
  Andreas Oehler
  

• Ian (two Bromptons) Oliver, Sep 2002:
  So far I'm very happy with the Son dynohub, but I'll see how it gets through the winter. It's been on all spring/summer and whenever I've wanted light I've got it. It's not too heavy, it's silent, and you just don't notice any drag at all.
  Fitting details at http://www.foxhill.co.uk/brompton/son1.htm

Dynamo charged battery backup

• Mark Lewis, Jun 1998:
  I thought very seriously about trying to insert some battery backup into the system but I thought the losses introduced by rectifying the dynamo's output to produce a DC supply for the bulbs and battery would introduce too great a loss of power in the circuit to make it worthwhile. Even using Schottky barrier diodes to do the rectifying there's still a loss of one volt from the six volts which equates to a 16% loss. Add to this the complication of isolating either the dynamo or the lights from the frame and I didn't think it was worth it at the time. I also couldn't fit the battery box I had in the main frame tube. All this could change when I get around to getting a new dynamo, though. The new one may be easier to isolate from the frame and I may be able to find a battery box that will let me get 6 volts worth of small Ni Cads into the frame. If I can I'll give it a try!

Wiring

• Andrew Henry:
  If you have a front and rear light running off a dynamo, then you need two wires running between the front and back halves of the bike. There is a lot more chance that these will get damaged whilst being ridden or folded.
• Custfold, Feb 1998:
  I find that loudspeaker cable is very neat and very effective - the polarity marking is particularly useful with bikes so that the Earthed line can be identified.
  An alternative option which works but looks a bit odd - is to solder terminations (or solder direct) a shaver coiled flex from front to back of the B - it stretches to acommodate folding, and slowly returns when the bike is assembled.

Where to mount a bottle dynamo?

• Dave Holladay, Jul 1997:
  You can fit the Nordlicht and other types of dynamo to the mudguard stay hole on the right leg of the front fork of the Brompton with a little careful adjustment, and still fit the mudguard stay onto the same point.
• Bolting dynamo bracket to front for: due to taper of fork it might slide down with vibration. However the bracket can be mounted on the mudguard stay mentioned above or just above it, so that it is quite firm (it is on my T5).
• Fitting dynamo to mudguard bracket: definitely not strong enough
• Welding a bracket to rear frame - not a DIY project.
• Phil Gough, Sep 1997:
  A Nordlicht fitted on the tab on the rear carrier of my now elderly T5, replacing the original Soubitez. A little nibble had to be taken out of the mudguard to clear the centre nut of the pulley wheel.
• Wherever you mount the dynamo, there is some concern that it might come loose with vibration, which is stronger on a small wheeler, and get caught in between spokes. In my opinion this is only possible if the dynamo is mounted backwards.
• Andrew Henry, Sep 1997:
  It does make a difference which side of the fork or seat stay the dynamo points at. If the dynamo is behind the fork blade, the rotation of the wheel tends to increase the grip of the dynamo wheel. The other way tends to decrease the grip.
  You also need to mount the dynamo on a stiff bracket or you will work more at bending the bracket than making the dynamo work.
• Phil Gough, Sep 1997:
  Someone told me that a front mounted generator, being pushed around on an undriven wheel is harder work than a rear-mounted one.
• Stein Somers, May 1998:
  [...] the dynamo stay tore off this weekend! The same thing happened on my other T5. Wise advise: do not just replace the standard T-model lightweight dynamo with a better but heavier one, mount it on a proper solid stay! I have never had the small Axa IQ that comes on T-model nowadays by the way.
• Stein Somers, Nov 1998:
  I replaced the original dynamo on two T-Bromptons and both dynamo brackets tore off after a month or two, I think because the dynamo's are heavier and the tyres more pressurized (less damping) than on an original Brompton. The Nordlicht is now on the left side of the rear wheel, on a simple and solid home-brew bracket. I expected the thing to slowly vibrate loose and get stuck in the wheel one day but it's still perfect.
  • Roland Elsenberg, May 1998:
    On my new Brompton (143458) of the four stays holding the rear of the rack the one holding the dynamo doesn't look like alloy and gets attracted by a magnet. Perhaps this will last.
• Roland Elsenberg, May 1999:
  I "lost" the Nordlicht back when I just had the old B where the dynamo was attached to a carrier-stay of aluminium. As I could neither do without light nor without Brompton that winter I drilled 3 holes into the carrier-stay (I was convinced I had to replace it anyway). Then I drilled 3 matching holes into a square piece of aluminium (5cm X 5cm). This piece got a larger hole to fit the screw that normally holds the dynamo.
  This construction was intended to last until the new carrier-stay arrived. In the meantime, about 1.5 years, I forgot to order it. Glad You reminded me...
  On newer Bromptons the carrier stay that holds the dynamo seems to be made of steel and the AXA iQ is used. This is very light and has given no trouble at all during the last year with my new T5.
• Andy Follis, May 1999:
  One of the Brompton users in Edinburgh [David Hansen] has a dynamo mounted to the front stay and seemed happy with it last time I saw him. I'd be nervous always remembering the front stay mounted battery light that decided to eat my spokes one day in about 1969. I ate tarmac but at least had a few days off school.
• Custfold, May 1999:
  I have fitted the Nordlicht to :
  1. the front forks (RH) to run on the rim or tyre - the latter allowing you to keep the stay fixing and (just) fit in under the stay.
  2. the rear 'seat' stay on the LH side and running on the rim.
  The OEM mounting point is not really substantial enough for a dynamo like the Nordlicht, and easily bent out of alignment.

Slipping tyre-side dynamo

• Stein Somers:
  I noticed the dynamo gives up after half an hour on wet roads, even when it is not raining anymore.
• Channell Wasson:
  I use my Brompton Dynamo light regulary, and I expect to use it more when Daylight Savings time disappears and the rainy season. Until that time--- I can say for now the system has worked flawlessly for me in the sunny California season. I have found that the dynamo can slip--especially on the new Primo hi-pressure tires. To correct this I snipped off a piece of a 1" inner tube and put it over the end of the knurled dynamo rotor. Now all works well.
• Meryl Prestidge:
  I gave up on the stock dynamo on my T5 very quickly, as it was completely useless in even slight drizzle (I blame the plastic roller). [...] I think it's a shame to spoil such a nice bike with a naff dynamo when a good one would make an insignificant difference to the cost.
• Stein Somers:
  After a while, even my Axa HR started slipping, though much less.
• Meryl Prestidge:
  I've been told to lubricate it with light mineral oil occasionally.
• Channell M. Wasson, Feb 1999:
  Yes it's still rubbing/rolling gently on a Primo. I mounted two O-rings near the very top of the dynamo head and glued them appropriately (super-glue or 5 minute epoxy) Then I mounted a third o-ring so that it rides in depression between the two glued o-rings. Glued this o-ring too but was careful to leave the soft neoprene exposed to the primo tire clean of any glue. With a little adjustment and a bit of mudguard clipping, the dynamo can also be made to run on the black tire rubber of the primo. Works very well and has been doing so worry free for some time. W'ere in our rainy season now and it works in the wet too. I also use a halogen gas bulb in the front (6 volt 2.4 watt)--gives a good bright light. The resulting larger diameter dynamo head runs a bit slower, but this does not seem to noticeably diminish the brightness of the headlamp during normal around town riding.
• Mike Paley in Millom, Jul 2000:
  Failing those, there's always temperature - the grease goes a bit stiff in the cold ! With a little use, the dynamo warms up - problem solved.
• Spotlight on lights - Electrical power supplies

Auto-engaging bottle dynamo

• Even my Axa HR started doing this after a while. I suggest to keep a Brompton free of dynamo's that pivot around a vertical axis and require you to push on the dyanmo to switch it on, because its mass will switch it on by itself during bumpy rides. Especially with firmly pressurized Primo tyres, the small inflexible wheels seem to tranfer bumps more than big-wheelers.
• Channell Wasson:
  If your dynamo comes on over bumpy terrain buy a spring or a piece of spring wire, and instal it at the dynamo bolt on so that pressure of the spring holds the dynamo up. Then it will not come down over detent and turn on. Also I have had success using one or two o-rings over the dynamo head for better traction against the tire. This also reduces power output on down hills and reduces possible bulb blow out.

Blown tail lights

• Stein Somers:
  After 30 mintues of riding in the dark, gone was the rear light. The bulb was quite black. I put in another 6V 0.1A, and measured over 7V, peddling fast but in 2nd gear only! No wonder the front light was so bright. So I replaced the front 2.4W with a 3.0W, so the voltage would exceed 6 only while peddling fast in 4th gear. It took 2 weeks before the read bulb burned through again.
• Andrew Henry:
  The best solution is to use a voltage regulator using Zener diodes. There are some instructions on how to build one at http://www.bath.ac.uk/~bspahh/bikelights/lights.html
  A better solution might be to get a Busch and Müller Lumotec front light as this includes a voltage regulator. It also comes with a halogen bulb which is a little bit more efficient. You don't want to use a halogen bulb without a voltage regulator as they are more expensive to replace and are more sensitive to high voltages.
• Malcolm J New:
  To reduce (hopefully eliminate) the risk of blown rear bulb on my T5 dynamo light I have fitted a an "Xi" Reflectalite Universal cycle dynamo regulator. This gadget : "controls the output from any cycle dynamo, including sidewall, centre tread and hub types" It cost me £4.06 (Sterling) from an old fashioned cycle shop in Chichester W. Sussex. UK
  Ian Ringrose:
  You were done, the bits to make one only cost about #0.14 (Sterling) and you then need to make 2 joint with a solder icon.
• Phil Gough:
  When my T5 was new it used to go through rear lamp bulbs at a great rate, which at the time i thought was due to a few million duff ones getting onto the market. Now several years later, with the original rear end wiring still intact, I have been using the same bulb for nearly 3 years. I put this down to the oxidation of the contacts increasing resistance and lowering the voltage a little.
• Stein Somers, Feb 1999:
  The Axa IQ that new T-model Bromptons are equipped with, does not feature voltage regulation (i.e. two 0.1 Euro worth Zener diodes), so expect more blowing light bulbs.
• Channell Wasson, Mar 1999:
  We will have bulbs and regulators (for control of excessive current) available in three weeks for your Brompton and what a difference they make over the normal vacuum bulb! Prices: Bulbs $6.50 Regulators $8.00 Shipping $3 cw

The Brompton Folding Bicycle FAQ