Dynamo system choices

For discussions about bikes and equipment.
Giles Pargiter
Posts: 65
Joined: 15 Sep 2012, 11:34pm
Location: N & Mid Wales.

Re: Dynamo system choices

Postby Giles Pargiter » 13 Jan 2018, 11:11pm

I know it is deeply unfavoured and unfashionable in the UK but I use modern B&M bottle dynamos on my bikes, upon which I do a considerable amount of night riding.
These are the lightest type of dynamos available and due to the fact that they revolve much faster suffer from no flicker at all even when wheeling the bike. When turned off they are completely off.

One is connected to a Philips 60 Lux front light mounted to the stem pinch bolt - in exactly the position the OP desires - chosen to cast negligible wheel shadows. I think this light may no longer be available. It comes from Rose bikes who regard it as a vital "component" not a desirable "accessory" and accordingly price it reasonably.

The other is connected to a much cheaper B&M lamp, from the same source, that from memory I think is 50 lux. Both have provided faultless frequent service for long periods in all sorts of weather over the last 10-12 years. I nowadays only carry a tiny pen torch to light my very infrequent "mechanical s" such as punctures when necessary.

All "bicycle" lights from Rose cycles, unless specifically stated otherwise, properly comply with the Stvzo(?) reg's and so have a proper beam shape and are actually legal to use. I can also mention that I don't think you will have any trouble with their service.

The bike fitted with the Phillips light frequently descends mountain roads at night, sometimes at speeds approaching 50mph and I regard the beam as suitable for this. If I remember correctly a motor vehicle dipped light is 80 lux.

SA_SA_SA
Posts: 1713
Joined: 31 Oct 2009, 1:46pm

Re: Dynamo system choices

Postby SA_SA_SA » 13 Jan 2018, 11:29pm

Giles Pargiter wrote:...Philips 60 Lux front light....I think this light may no longer be available....

Philips sold the designs to Spanninga who repackaged it and updated its electronics as the Axendo 60
http://www.spanninga.com/products/headlamps/axendo-60/

Nicer case but althought the last Philips lamps were upgraded to a neutral white (less blue) LEDs spanninga have relapsed to a colder white....Bahhh
------------You may not use this post in Cycle or other magazine ------ 8)

Giles Pargiter
Posts: 65
Joined: 15 Sep 2012, 11:34pm
Location: N & Mid Wales.

Re: Dynamo system choices

Postby Giles Pargiter » 13 Jan 2018, 11:59pm

That is interesting SA-SA-SA. I didn't realise those points about the Led colours, nor that it was re-branded. I do know that I regard it as very effective. I bought it in around 2005-6, it has worked faultlessly ever since. That actually makes it a very cheap light when one considers the options. I think it was around 60 or £70, only in euros.
Also interesting what you say of the case, I started out by wrapping a bit of tape round mine to make it look repaired and thus entirely undesirable, now the paint is coming off the aluminium case to enhance the effect. The light continues as new!

Brucey
Posts: 34200
Joined: 4 Jan 2012, 6:25pm

Re: Dynamo system choices

Postby Brucey » 14 Jan 2018, 1:18am

andrew_s wrote:
Brucey wrote:the IQ-X has a noticeably better spread than some other models, and should allow fairly tight turns to be negotiated with confidence.

cheers

The beam width doesn't really help.
With the sharp cut off, and the bike leaning over into the corner, the inside edge of the beam just lights the near part of the verge, and you still can't see round the corner. If you slow down enough to keep the bike upright, you don't really need the light.


It depends on how fast you are going, how high up your light is mounted (yes higher is better here), and (of course) it does depend on the beam shape..... :roll: My comment was that the IQ-X beam is better in this respect than the others that I have seen. I didn't say wider......

You (or anyone else) can look at the beamshots available online and make your mind up for yourself. Whether it is going to be judged good enough for anyone is dependant on a whole load of things including what is going on between the ears.... :wink:

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

User avatar
andrew_s
Posts: 4781
Joined: 7 Jan 2007, 9:29pm
Location: Gloucestershire

Re: Dynamo system choices

Postby andrew_s » 15 Jan 2018, 2:25am

Brucey wrote:You (or anyone else) can look at the beamshots available online and make your mind up for yourself.

Online beamshots are universally made with the bike vertical, as it would be when the bike is going in a straight line.

StVZO lights like the IQ-X exhibit a horizontal division between lots of light (below), and very little light (above). In the case of the IQ-X, this division is reportedly particularly sharp.
If you are "cornering with confidence", the division will no longer be horizontal, but at an angle of maybe 15 or 20 degrees, depending on corner and speed. That part of the beam on the low side of this angle, towards which you are turning, doesn't reach far enough to usefully show you where you are about to be riding.

What does "a noticeably better spread" mean, if it doesn't mean wider?

Brucey
Posts: 34200
Joined: 4 Jan 2012, 6:25pm

Re: Dynamo system choices

Postby Brucey » 15 Jan 2018, 11:04am

if you bother to look at the beamshots on the B&M site, you will I think find that they have been taken in an underground car park. Accidentally or otherwise, there are illuminated objects to each side (for example there is a door on the LHS side of the illuminated field IIRC), well above and to the side of the cutoff in the main beam, so you can judge quite well what the spread of the beam is really like (for sharp corners), relative to other lights that are presented similarly.

What struck me when trying an IQ-X was that the beam seemed better spread than other lights I have used; similarly I was struck in that the spread looks better (in particular, said door is much better illuminated for example) vs other lights in the beamshot.

As I have repeatedly suggested, you need to look for yourself and make sure that it meets your requirements; there are hundreds of lights out there and a suggestion that you should consider some rather than others might cut down on a lot of futile effort....

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

brynpoeth
Posts: 10076
Joined: 30 Nov 2013, 11:26am

Re: Dynamo system choices

Postby brynpoeth » 15 Jan 2018, 11:12am

Giles Pargiter wrote:I know it is deeply unfavoured and unfashionable in the UK but I use modern B&M bottle dynamos on my bikes, upon which I do a considerable amount of night riding.
These are the lightest type of dynamos available and due to the fact that they revolve much faster suffer from no flicker at all even when wheeling the bike. When turned off they are completely off.

..
.


Unfashionable is good I think
Like to see some pictures, front or back? Diolch
I was always a bit afraid a bottle dynamo might go into the spokes
Entertainer, juvenile, curmudgeon
Cycling-of course, but it is far better on a Gillott
We love safety cameras, we love life

User avatar
NUKe
Posts: 3617
Joined: 23 Apr 2007, 11:07pm
Location: Suffolk

Re: Dynamo system choices

Postby NUKe » 15 Jan 2018, 11:18am

I would concur with Brucey the Spread is excellent. Having used the Cyo range for about 5 years I recently added an IQ-X to the stable. If set right it gives good light but the cut off does not Dazzle drivers, Never had any problems with Sharp corners. Even leaning the bike over, like everything else though, ride to what you can see.
I slightly angle mine so the nearside is higher, this does help with illuminating the left and as left will always be a sharper corner than a right perhaps this helps.
NUKe
_____________________________________

Brucey
Posts: 34200
Joined: 4 Jan 2012, 6:25pm

Re: Dynamo system choices

Postby Brucey » 15 Jan 2018, 11:24am

NUKe wrote: I slightly angle mine so the nearside is higher, this does help with illuminating the left and as left will always be a sharper corner than a right perhaps this helps.


that sounds like a good idea; dip beam patterns on cars are skewed leftwards but thus far such shaped beams have not appeared in bicycle lights.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

User avatar
andrew_s
Posts: 4781
Joined: 7 Jan 2007, 9:29pm
Location: Gloucestershire

Re: Dynamo system choices

Postby andrew_s » 15 Jan 2018, 12:57pm

Brucey wrote:if you bother to look at the beamshots on the B&M site, you will I think find that they have been taken in an underground car park. Accidentally or otherwise, there are illuminated objects to each side (for example there is a door on the LHS side of the illuminated field IIRC), well above and to the side of the cutoff in the main beam, so you can judge quite well what the spread of the beam is really like (for sharp corners), relative to other lights that are presented similarly.
I've seen them, and the previous underpass beam shots.
The underground car park is particularly misleading, with a pale grey floor and white ceiling and pillars which reflect a great deal more light than typical roads, hedges, or the sky. Regarding everything outside the direct beam as being completely unlit would be far more realistic.
I'd recommend that you look at Peter White's beamshots.

Brucey
Posts: 34200
Joined: 4 Jan 2012, 6:25pm

Re: Dynamo system choices

Postby Brucey » 15 Jan 2018, 2:34pm

andrew_s wrote:
Brucey wrote:if you bother to look at the beamshots on the B&M site, you will I think find that they have been taken in an underground car park. Accidentally or otherwise, there are illuminated objects to each side (for example there is a door on the LHS side of the illuminated field IIRC), well above and to the side of the cutoff in the main beam, so you can judge quite well what the spread of the beam is really like (for sharp corners), relative to other lights that are presented similarly.
I've seen them, and the previous underpass beam shots.
The underground car park is particularly misleading, with a pale grey floor and white ceiling and pillars which reflect a great deal more light than typical roads, hedges, or the sky. Regarding everything outside the direct beam as being completely unlit would be far more realistic.
I'd recommend that you look at Peter White's beamshots.


They are interesting, except IIRC they are pointed at the ground, which does not necessarily even show you the part of the beam that might be relevant when you are going round corners.....

As I mentioned previously a good use of any beamshots is to compare beams with one another. No beamshot is going to replicate an exact road condition, (or reproduce anything, er, reproducilbly if the surfaces might vary with the weather, how wet/dusty they are etc), so past seeing a splodge of light up the road (which many lights will manage these days) you are left wondering how uniform that light is, what shape it is, and how much spread/spill there is in the beam.

You get an impression from some beamshots what they are like to use but unless you understand very well how reflective any plants are etc and how well low levels of light are captured and reproduced in the image then you don't really know what it will be like to use. A trivial example might be how grass looks; obviously it is going to look different depending on whether it dry or wet or frosty or dusty. It also looks different at different times of year, and unless you happen to know what species it is (it can be rough or smooth leaved, different colours etc) you
a) really don't have a clue what it is meant to look like and
b) it can vary anyway.

Arguably it is more meaningful to have the whole field of view to be a known reflectivity if you wish to make valid comparisons between lights, particularly as both the camera and the display medium used to view the resulting image will have a strongly 'S' shaped response curve, with less dynamic range than the Mk1 eyeball. This means that objects that are not very reflective, out of the main part of the beam, are just going to look various shades of black in a picture, which isn't easily going to tell you if one lamp is really much better/different than another when you are actually using it. It is also useful if there are objects at various distances in that part of the beam which isn't the main part of the beam, if you see what I mean.

I think that the folk at B&M who selected an underground car park for their beamshots understood all this very well. In addition that location will be (unlike most others) largely unaffected by current and recent weather conditions. It shows very well that there are meaningful differences between the lights that they make, which is their primary objective.

If you wanted to make truly comparative beamshots in different locations, (using different cameras and then display equipment) and/or in even one external location, you would need some means of establishing the absolute reflectivity of particular surfaces, and how the equipment records particular illumination levels too.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Samuel D
Posts: 2693
Joined: 8 Mar 2015, 11:05pm
Location: Paris

Re: Dynamo system choices

Postby Samuel D » 15 Jan 2018, 5:16pm

I have thought that photographing the beam from the lamp’s position as it hits a flat, perpendicular, evenly grey wall would be most informative. The camera’s exposure would have to be kept consistent between lamps and low enough to show detail in the brightest areas, and this would necessarily render the rest of the image dark because of the low dynamic range of a typical display (and 8-bit JPEGs). And of course such a beamshot would not be intuitive but require interpretation. All the same, it would show exactly where the light is distributed, including that above the top edge of the principal beam – something that is exaggerated in underground car parks or tunnels and missed altogether in most open-air scenes.

User avatar
andrew_s
Posts: 4781
Joined: 7 Jan 2007, 9:29pm
Location: Gloucestershire

Re: Dynamo system choices

Postby andrew_s » 15 Jan 2018, 5:53pm

Brucey wrote:Arguably it is more meaningful to have the whole field of view to be a known reflectivity if you wish to make valid comparisons between lights, particularly as both the camera and the display medium used to view the resulting image will have a strongly 'S' shaped response curve, with less dynamic range than the Mk1 eyeball. This means that objects that are not very reflective, out of the main part of the beam, are just going to look various shades of black in a picture, which isn't easily going to tell you if one lamp is really much better/different than another when you are actually using it. It is also useful if there are objects at various distances in that part of the beam which isn't the main part of the beam, if you see what I mean.
Objects out of the main part of the beam looking black is the drawback of Peter White's beamshots (the aim is pretty good, for a light aimed not to dazzle oncoming road users, for the more recent, brighter lights anyway).

However, the B+M beamshots go too far the other way, in that things out of the main beam (like the door on the left) are so brightly lit by light scattered out of the main beam by light-coloured paint that any light direct from the light in question is just swamped, so you've no idea whether or not you would be able to see anything there in real outdoor conditions.

I'm not alone in finding that the more recent wide-beam German dynamo lights (Luxos & later) don't allow faster cornering as much as might be hoped from beamshots and straight road riding.
The last time I replied to such a post, I (not very helpfully) said "that's what happens when the bike leans over; try riding a trike instead", and pointed out that nobody was going to justify trying to develop a dynamo-powered stabilisation system that kept the light level when the bike wasn't.

Brucey
Posts: 34200
Joined: 4 Jan 2012, 6:25pm

Re: Dynamo system choices

Postby Brucey » 15 Jan 2018, 6:40pm

andrew_s wrote: the B+M beamshots go too far the other way, in that things out of the main beam (like the door on the left) are so brightly lit by light scattered out of the main beam by light-coloured paint that any light direct from the light in question is just swamped, so you've no idea whether or not you would be able to see anything there in real outdoor conditions.
.


I don't disagree that those beamshots don't tell the whole story, but no (single scene) beamshots ever will, I think. I think they are very useful for those currently running older model lights, since one can see if there is a significant improvement in the newer models or not.

BTW if the light scattered from the main beam were a big effect, one would expect to see shadows arising from it. I have not checked to be sure, but I don't remember noticing any.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

User avatar
andrew_s
Posts: 4781
Joined: 7 Jan 2007, 9:29pm
Location: Gloucestershire

Re: Dynamo system choices

Postby andrew_s » 15 Jan 2018, 8:10pm

Brucey wrote:BTW if the light scattered from the main beam were a big effect, one would expect to see shadows arising from it. I have not checked to be sure, but I don't remember noticing any.
There are no shadows. This is because everything outside the main beam is diffusely lit by the bright floor & ceiling, brightly enough that any light directly from the IQ-X is not significant.
If you look at the Cyo Premium beamshot, there's an area just to the left of the 2nd pillar on the left that you can just about see is lit by the Cyo.
The same area is not visibly lit by the IQ-X. It probably is, but because it's so much more lit by the ceiling and pillars, you can't tell.