A Last Light Question (from me anyway)

Graham O · Post by **Graham O** » 31 Oct 2008, 7:05am

Well my new dynamo turned up yesterday from Germany. Ordered Monday and delivered Thursday. Well done www.roseversand.com. The big question now is about a front light. The choice is going to be either B+M IQ Fly Senso or the IQ Cyo. However I am a bit lost after reading their website. Am I right in thinking that the Cyo has 60 Lux output because it has a more concentrated beam than the Fly which has a more dispersed beam? There is a beam pattern for the Cyo, but not for the Fly. Any help much appreciated.

Of general interest, I've found the recent bit of information on an American site:

The output claimed is 40 lux at ten meters. As the light patch is about 12 square meters at this distance, this equals about 500 lumen worth of output...out of a 6V/3W dynamo hub...

The good thing about this is that it sums up the science of Lumens vs Lux. Lux is the density of lumens, i.e. lumens per square metre at a specific distance. This is much more useful than just Lumens as it gives some idea of the lights illumination properties, provided the beam pattern is shown or defined. So it is a bit frustrating that the beam pattern for the Fly isn't shown.

worrywort · Post by **worrywort** » 31 Oct 2008, 7:57am

I don't mear to be pedantic, but the only real test is to use them in the dark. they are all differeint depending on your environment. why not use two?

Graham O · Post by **Graham O** » 31 Oct 2008, 8:23am

At £60 each, trying both could be expensive! My query is that the beam pattern is only shown for one of them. If I can get a brighter one for nothing, then I'll go for the brighter one, but brightness isn't everything, so I just want some pre-purchase reassurance.

rualexander · Post by **rualexander** » 31 Oct 2008, 9:23am

As far as I can see the difference between the IQ Fly and the Cyo is the fact that the Cyo has more light shining immediately in front of the bike (near field illumination they call it), further out the beam is pretty much exactly the same. Have a look at this page on B&M website,
click 'innovations' then 'Lumotec IQ CYo':

http://www.bumm.de/index-e.html

Some good beam shots here also but not Cyo

http://www.peterwhitecycles.com/headlights.asp

I have just bought an Ixon IQ but not tried it out yet, test this weekend.

james01 · Post by **james01** » 31 Oct 2008, 9:41am

I have been using a Cyo for a couple of weeks (the "Sport" 60 lux, not the 40 lux model which incorporates a reflector in the lens). I have also been using a Fly IQ for several months on another bike, and until the Cyo it was the best dynamo light I'd ever used. The Cyo has a very similar beam pattern to the IQ, the only difference I can be sure of is that the Cyo is even brighter. Now that the Cyo is available, I can't see any reason to choose the Fly, and I assume Busch & Muller will phase it out.

Graham O · Post by **Graham O** » 31 Oct 2008, 9:51am

Thanks Rualexander, the link to Peter White Cycles was most useful. I'm looking forward to being able to see that well! I think that the IQFly can be set to 3 positions, to give near field or distant, while the Cyo covers both at the same time. Decision time this afternoon.

Kevin K · Post by **Kevin K** » 31 Oct 2008, 9:57am

I've been looking at this too. So far as I can work out the 40 & 60 lux models are technically identical. The difference seems to be in the distribution of light.

It seems to me the 40 places 40 lux of light 10 metres ahead and and the rest closer to the bike. Whereas the 60 places 60 lux of light 10 metres ahead but none close to the bike.

Kevin

james01 · Post by **james01** » 31 Oct 2008, 10:04am

Graham O wrote:Thanks Rualexander, the link to Peter White Cycles was most useful. I'm looking forward to being able to see that well! I think that the IQFly can be set to 3 positions, to give near field or distant, while the Cyo covers both at the same time. Decision time this afternoon.

The 3 positions feature on the Fly is a bit of a gimmick, the adjustment is too coarse. With middle position just right for normal ridng, the highest setting lights up the treetops & the lowest gives you an incredibly bright but rather useless apron of road immediately in front. I just leave it on middle setting. The Cyo is easy to tilt manually on it's fixing clamp if you need to adjust the beam. If you order the Cyo, make sure they don't send you the 40 lux German home-market version which has a reflector obscuring part of the lens.

Graham O · Post by **Graham O** » 31 Oct 2008, 10:36am

Thank for the extra information. Having looked at the Roseversand website, kwkirby02 is correct. The Cyo 40 does have near field illumination while the Cyo60 is brighter because it does not have near field illumination, so the lumens are more concentrated hence the higher Lux value.

Now I just need to know if I want/need near field illumination? Decisions, decisions!

natmat · Post by **natmat** » 31 Oct 2008, 10:55am

Graham O wrote:Now I just need to know if I want/need near field illumination? Decisions, decisions!

I would say it depends on your speed and road conditions. Riding 20+mph on unlit country roads I'm not bothered about near-field illumination, by the time I see something that close it's too close to avoid.
If you're cycling in lit towns, then the road will be lit sufficiently for you not to need the near field either.
I can only think I'd use the near-field (e.g. click-down on the IQ Fly) if I were going slowly on open un-lit roads or Mountain biking at night.

Oh, I'd second the comment the IQ Fly's 3-click directional adjustment is pointless. I don't use it at all and wouldn't want to risk using it if it resulted in the directed beam jiggling around as the clicks became worn.

Nat.

james01 · Post by **james01** » 31 Oct 2008, 10:56am

My impression is that the 40 lux version is for the low speed "shopper" cyclist, also it has a reflector built into part of the lens ( to comply with local laws)which must surely affect light output compared with the 60 lux "Sport" model, which has a completely clear lens. I find that the close-up output of the Sport is very good.

EdinburghFixed · Post by **EdinburghFixed** » 31 Oct 2008, 10:58am

Graham,

I think it depends a lot on how fast you ride. On my commute I can choose between bar light and helmet light (or both) as the situation demands. The faster I'm going, the less I'm bothered by 'dark near field' - and the more I want to be able to see at a distance.

Personally I would go for the light with the longest throw, as you can always do with a bit more distance visibility, if you had to negotiate a rugged trail at walking speed you could just tip the light down...

Graham O · Post by **Graham O** » 31 Oct 2008, 11:01am

The reflector need not affect the light output if it is designed with the reflector in place and since it is quoted as 40 Lux, which is measured down field of the light, (and assuming German efficiency) then 40 Lux is 40 Lux.

I'm tending towards the Cyo 60. I'll be riding on unlit country lanes and if I find that near field is needed, I can adjust the angle of the light accordingly. I'm getting the system principally for commuting and since I know the roads , I know where the potholes are.

Graham O · Post by **Graham O** » 31 Oct 2008, 11:08am

Unfortunately Rose is waiting for deliveries of the Cyo in week 44. Anyone know when that is please?

The dynamo I have is the Shimano DH3N80 which came with an overvoltage protector. Is this just used for halogen bulbs and is not necessary with the Cyo? I'm assuming so.

Does anyone have the mudguard fitting 4D Plus rear led light? Is it worth the money to give me an all dynamo powered trouble free system?

james01 · Post by **james01** » 31 Oct 2008, 11:34am

http://www.bike24.com/1.php?content=8;p ... 43b3c3815d

I've got one of these, €12.90 and very bright & has a standlight, but it's rack-fitting.