Stop All the Clocks

Say it quietly, but as from today the days are just getting shorter. I know it puts a downer on the weekend but my glass is not half empty, I'm at my Sister's celebrating her birthday so no chance of that.

Between today and the 26 October when the clocks go back a riders thoughts should turn to lights. Whether it's checking over last seasons, did you discharge your rechargeable and fully recharge it before putting it away? or researching this winter's illuminating lovely, prior planning prevents poor performance. Retailers are starting to plan their stock for the lighting season so you the customer can ease their decision by deciding sooner rather than later what you are going to use.

Are you finally going to indulge in a dynohub front wheel and light system that just works? Upgrade to a decent rechargeable system? Or just spend a tenner on a piece of junk off of eBay with no warranty or beam pattern but it has a big lumen number and Cree LED in the title? Why not do the research on what Lux, Lumen and Candella actually mean and where manufacturers measure them. Have a look at the beam pattern maps that more enlightened manufacturers publish then make an informed decision. Heaven forfend but you could even pass your information around and help to quash the torrent of BS that is out there about bicycle lights.

The darkness is coming, be ready.  

Busch and Muller Ixon Core / IXXI Twin Pack

Busch & Muller IXXI / Ixon Core Twin Pack

Yesterday I got my hands on the new USB rechargeable lights from Busch & Muller. I've had access to the Ixon Core for a while but wanted to do a user check on them both. I have been using the original Ixon for 6 or 7 years now and am hugely happy with it. On a personal level I couldn't understand why you'd want a lesser light. I appreciate however, some customers buy with their pocket. In my previous life as a retailer the head to head for rear lights went between two well known brands. The considerably brighter light lost out as the lesser light was ten bob cheaper. The brand name may have come into it but at source the cheaper light was bigger, heavier and nowhere near as bright.

So, twin packs. Usually an excellent light matched up with an okay light at what appears a budget price. The B&M can't be called cheap at £67.50 RRP but, “What price your safety?” as Sorrel's Mum always says. If you live in a town this twin pack should be well up the list for consideration IMHO. My old shop's best selling twin pack had a poor front light and a fabulous rear light yes it was cheaper but you'd need a second front light in reality.

Burn times. In a far from scientific test I discharged both lights totally and then charged the IXXI from the mains for 2 ½ hours and the IXON Core for 3 ½ as stated in the instructions. The IXXI stayed lit for around eighteen hours. The Ixon Core burn time is quoted as more than 3 hours actually ran for the best part of four. This does include the time in low power mode which is considerably longer than the 10-15 minutes my old Ixon gives me. So no mean shakes for a 50 Lux light with a good beam spread on the road.

Attachment to the bike for both lights is by the now ubiquitous rubber strap. The Ixon can be clicked out of its' mount as well so if you have to thread your strap through cables you can leave the mount on the bike.

Charging. Both lights charge with the industry standard micro USB plug so unless you insist on using CDHoJ products your phone/tablet cable will fit. I'm not a great fan of charging off your computers USB ports but over the course of a working day you'll get a fair top up. Come the revolution charging towers will be a part of secure bike parking areas.

So as an in town commuter twin pack I think this is a good package no matter what rear light you use, in town you'd double up with a flashing light as an attention getter.  So there is my early punt into the 2014 lighting season

On Bicycle Lighting 3

If you have a basic physics grounding and/or have researched buying a bike light lately you are probably a mite confused right now. All the manufacturers seem to rate their lights with different methods whether that is watts, candela, lumen or lux and it just muddies the water for the punter on the street.

To clarify my stance early on, I work for Amba-Marketing, the UK distributor for Busch & Muller and Supernova. I bought my first B&M light in the late 1990s (Thank you SJS Cycles) nearly a decade before I left the military and entered the bike world . Over the last 20 years I have used lights from B&M, Smart, Axa, BLT and Cateye for both battery and dynamo. I was given a B&M Ixon IQ by Amba the first winter they were on the market as a sales bonus/trial. I will not hide my respect of B&M's lights they have served me well on tours, club rides and some mostly unlit rural commutes. From my first halogen fuelled Oval to my current LED Oval+ with my trusty Seculite or D-Toplight depending on the bike, I'm now a kid in a sweetshop genuinely unsure what to replace the Oval with.

You only have to visit a cycling forum to discover a variety of differing opinions on what light to have. The trouble is once you get past, “It says 300 million lumens and only cost me a tenner” what do you actually know? So in the third of a number of blogs on terminology todays subject is;

Lux

This is where the two previous articles meet up and all nearly becomes sweetness and light. Lux is the SI unit of illuminance and luminous emmitance, measuring luminous flux per unit area. Illuminance is the total luminous flux incedent on a surface per unit area, it is a measure of how much light illuminates the surface based on an average sensitivity of human perception of brightness. We all see light differently depending on our eyes so science uses a known average, So what we have is lumens = Quantity and Lux = intensity on a surface.

It is arguable that Lux is a more useful unit for the comparison of bike lights which is our initial quandary. However, alone it is also fairly useless unless you have the distance the light is measured from the source. Also it says nothing about field, consistency or colour of the light. So we may have 100 lumens at a point x metres from the lamp but what is the reading 5cm in any direction? We just dont know. So a field map of the light intensity helps us but only if all the manufacturers produced their output in a standard format (Flying Pig1, this is air traffic, remain on pan awaiting clearance to taxi) Power isn't everything, because how you feed all this light through a lens also varies how much light goes where. My old IxonIQ has a third more lumens than the new IQ but the field pattern is much improved on the new model so in this case more lumens doesn't mean more light.

In conclusion while our three main measures used in bicycle lighting are all linked non of them tell us precisely what we want to know. If however a few key distances and comparable lumoinosity maps were included in the promotional bumph we might have half a chance of accurately comparing light a to light b. As it stands the closest we can get is the reviews in the paper press hoping the photog switched off autocorrect so they're all on the same aperture and shutter speed. Will the bike light industry buy into this? Some have but as there are so many tuppeny ha'penny mass manufacturers out there putting quantity over quality it's doubtful. So we're still going to be stuck with the guy on the club forum banging on about the 3K Lux light he got mail order from Ulan Bator. You know the one he'll have two on his handlebars and one on his helmet secured with duct tape and melting the retina's of any poor soul coming towards him so they cant see where they are going, he's fine though.

On Bicycle Lighting 2

The second in a number of items vainly intended to clarify the muddy waters of bicycle lighting terminology.

If you have a basic physics grounding and/or have researched buying a bike light lately you are probably a mite confused right now. All the manufacturers seem to rate their lights with different methods whether that is watts, candela, lumen or lux and it just muddies the water for the punter on the street.

To clarify my stance early on, I work for Amba-Marketing, the UK distributor for Busch & Muller and Supernova. I bought my first B&M light in the late 1990s (Thank you SJS Cycles) nearly a decade before I left the military and entered the bike world . Over the last 20 years I have used lights from B&M, Smart, Axa, BLT and Cateye for both battery and dynamo. I was given a B&M Ixon IQ by Amba the first winter they were on the market as a sales bonus/trial. I will not hide my respect of B&M's lights they have served me well on tours, club rides and some mostly unlit rural commutes. From my first halogen fuelled Oval to my current LED Oval+ with my trusty Seculite or D-Toplight depending on the bike, I'm now a kid in a sweetshop genuinely unsure what to replace the Oval with.

You only have to visit a cycling forum to discover a variety of differing opinions on what light to have. The trouble is once you get past, “It says 300 million lumens and only cost me a tenner” what do you actually know? So in the second of a number of blogs on terminology today's subject is;

Lumen

The Lumen is the SI unit of luminous flux, ie how much visible light is emitted by a source. Note visible and emitted it is what's pumped out not what we get back. In simple terms it is to light sources what pints are to beer, but like beer all outputs are not the same. While a pint of beer seems black and white without the ABV it is not as helpful as you might think. The same with lumen. It's not how big it's what you're doing with it that counts. 100 lumen, bomb burst across the sky is less use to us as cyclists from our cycle light than 100 lumen focused where we want it. It is an objective measure of effective luminous output from a light. We need to know how big the area and how far from the light that is.

As with the candela the lumen as an indication of your light needs definition. We don't know how or where it affects our vision merely what there is coming out of the source. We do not know its colour spectrum or useful spread.

The relationship 'twixt lumen and candela can be seen on last weeks diagram as, here comes a difficult sum AmbaTechGuy will fail to answer but expects to see on tee shirts soon:

1 cd·4π sr = 4π cd·sr ≈ 12.57 lumens

Put into simpler terms: Luminous flux (in lumens) is a measure of the total amount of light a lamp puts out. The luminous intensity (in candelas) is a measure of how bright the beam is. If a lamp has a one lumen bulb and the optics of the lamp are set up to focus the light evenly into a one steradian beam, then the beam would have a luminous intensity of 1 candela. If the optics were changed to concentrate the beam into 1/2 steradian then the source would have a luminous intensity of two candela. The resulting beam is narrower and brighter.

Confused? It's just physics but it's beginning to show the limitations of the information on the box and we're not quite half way through my peripatetic ramblings yet. Meanwhile a picture is worth a word or twenty,

On Bicycle Lighting

The first in a number of items vainly intended to clarify the muddy waters of bicycle lighting terminology.

If you have a basic physics grounding and/or have researched buying a bike light lately you are probably a mite confused right now. All the manufacturers seem to rate their lights with different methods whether that is watts, candela, lumen or lux and it just muddies the water for the punter on the street.

To clarify my stance early on, I work for Amba-Marketing, the UK distributor for Busch & Muller and Supernova. I bought my first B&M light in the late 1990s (Thank you SJS Cycles) nearly a decade before I left the military and entered the bike world . Over the last 20 years I have used lights from B&M, Smart, Axa, BLT and Cateye for both battery and dynamo. I was given a B&M Ixon IQ by Amba the first winter they were on the market as a sales bonus/trial. I will not hide my respect of B&M's lights they have served me well on tours, club rides and some mostly unlit rural commutes. From my first halogen fuelled Oval to my current LED Oval+ with my trusty Seculite or D-Toplight depending on the bike, I'm now a kid in a sweetshop genuinely unsure what to replace the Oval with.  I do not put myself up as an expert and the text has evolved from a number of sources not just a C&P from Wiki.

You only have to visit a cycling forum to discover a variety of differing opinions on what light to have. The trouble is once you get past, “It says 300 million lumens and only cost me a tenner” what do you actually know? So in the first of a number of blogs on terminology todays subject is;

Candella

Scrubbing past the history, the current definition of Candella is,

The luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 x 10¹² hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.

Piece of cake? OK those Hertz and Watt figures. They give you a colour and intensity, which is roughly yellowish-green and is a color that the human eye is highly sensitive to.

Candella is a measurement of light at source, but neither it or Candlepower tells us how powerful the light is some distance away from the source. Instead, we measure the amount of light illuminating a surface area, which is called, naturally enough, the illuminance. The result is measured in lumens, with 1 lumen = 1 candela x steradian. For our purposes here we can think of the the latter term as an area, as the following example illustrates:

Imagine a transparent 1 metre radius sphere surrounding a candle. Its surface area will be given by 4 pi r², so the surface area of our sphere is:

4 pi 1² = 12.57 m²

The amount of energy passing through 1 square metre of the transparent sphere is 1 lumen, and so it follows that 1 candlepower is 12.57 lumens.

So in our bike light scenario the buyer has no idea where the candella has been measured or which direction the light is going or for that matter how many directions. So for our intents and purposes candella is fairly useless as it is a measurement of emitted luminous intensity and without knowledge of the emission cone meaningless.

Calm, there are more of these to come and much will become clear in time.