Front light positition

General cycling advice ( NOT technical ! )
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mjr
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Re: Front light positition

Postby mjr » 25 Sep 2019, 1:58pm

francovendee wrote:
rjb wrote:Anyone have these lights coming on sale in Aldi?
https://aldi.co.uk/p/017096282743300

I'd be interested also. Seems very cheap but are they any good?

No, they're MTB forest floodlights, as indicated by this in the description:
"Safety Warning
Lights are to be used in conjunction with lights complying with the Road Vehicle Lighting Regulations. "

The same applies to most lights sold in the UK so credit to Aldi for actually printing it when most shops don't. It would be better if they also sold better lights, like Lidl do.

Brucey wrote: FWIW Reflective tape doesn't work like that; the only light usefully reflected by it will be the light from the person in the side turning, and those lights are simply not pointed in the right direction.

I'll go test it later but I'm pretty sure reflective tape is much less directional than a retro reflector.

Brucey wrote:FWIW most motorcyclists live in fear of being SMIDSY'd and they are lit up like a christmas tree.

And being lit up like a tree doesn't seem to be working for them, so I'm not sure that's a great argument!

Brucey wrote: Riding around with only a fork-mounted lamp that is definitely obscured from certain angles is not going to improve your life expectancy.

It'll certainly improve it more than riding around without any lights! Of course, don't mount it high enough that the top of the rim will block the lamp over a wide area of other road user head heights, but the obscuring of a lamp mounted low on the fork will be minimal and fairly far ahead of the bike. Oh and I just remembered: for the above to apply, it's important that the illuminated surface area (lens or reflector, depending on design) is wider than the tyre!

brooksby wrote:
mjr wrote:I favour fork crown and back of the rack, but right handlebar and seat stay are also OK.

Legally, I think it has to be between a foot and six up (so no hub mounted lights on Bromptons) and centre or right hand side of the cycle.


Can you point at chapter-and-verse for that? I didn't know.

Now I'm at my desk, yes, and I was slightly off: http://www.legislation.gov.uk/uksi/1989 ... ule/2/made section 2(b)(ii)(B) is "On the centre-line or off-side of the vehicle" and 2(c)(i)(A) sets a 1500mm (not 1800mm) maximum height for the front lamp, whereas http://www.legislation.gov.uk/uksi/1989 ... le/10/made repeats those and section 2(c)(iii)(A) gives the 350mm minimum height which only applies to the rear lamp.
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
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brooksby
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Re: Front light positition

Postby brooksby » 25 Sep 2019, 2:19pm

mjr wrote:
brooksby wrote:
mjr wrote:I favour fork crown and back of the rack, but right handlebar and seat stay are also OK.

Legally, I think it has to be between a foot and six up (so no hub mounted lights on Bromptons) and centre or right hand side of the cycle.


Can you point at chapter-and-verse for that? I didn't know.


Now I'm at my desk, yes, and I was slightly off: http://www.legislation.gov.uk/uksi/1989 ... ule/2/made section 2(b)(ii)(B) is "On the centre-line or off-side of the vehicle" and 2(c)(i)(A) sets a 1500mm (not 1800mm) maximum height for the front lamp, whereas http://www.legislation.gov.uk/uksi/1989 ... le/10/made repeats those and section 2(c)(iii)(A) gives the 350mm minimum height which only applies to the rear lamp.


OK, thanks for that. I wouldn't want to get pulled over for having a light on the left side of my handlebars! :D

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Re: Front light positition

Postby scottg » 25 Sep 2019, 2:30pm

Had Stan Pike with a fork boss, for German style lights with a cut off it worked
very well, long throw down the road, good at picking out the bumps and lumps.
Mounted an IQ-X light to the brake bolt, using the Paul brake/rack bolt,
that worked well.

For round beam lights, I like the handlebar, so I can tilt them as needed.
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NUKe
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Re: Front light positition

Postby NUKe » 25 Sep 2019, 2:31pm

Mine is under the bottom bracket
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mjr
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Re: Front light positition

Postby mjr » 25 Sep 2019, 2:45pm

brooksby wrote:OK, thanks for that. I wouldn't want to get pulled over for having a light on the left side of my handlebars! :D

That's highly unlikely. It's far more likely that some weasel might try to use it as an excuse for knocking you off during a failed close pass because they thought your lights meant you were two feet further left.
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
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Tigerbiten
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Re: Front light positition

Postby Tigerbiten » 25 Sep 2019, 2:57pm

I like two lights.
My lower on at the height of my bottom bracket. It's set to just under the horizontal and slightly to the right of the center light. It's purpose is to illuminate as much of the road as possible. This is my steady dynamo light.
My upper light is around a foot higher. It's set pointing more down and slightly to the left of the center line. It's purpose is to illuminate the road close to the front of my ent trike so I can definitely see any potholes close in. This is a USB rechargeable light and can also be set to flashing if I'm riding under street lights.
I think something like this is probably about the best setup for front lights.
The main reason I've set my lights pointing slightly out is they're fixed to the frame of the trike and don't move with the wheels so I need to illuminate a wider area than a bike. This can make sharp high speed corners interesting as I don't illuminate very far around them ..... :D
If you do have a light to the left of the center line then you also need one to the right as well. Look how twin headlight motorbikes are set up. Just don't set them so far apart that you get mistaken for a car in the distance.

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Re: Front light positition

Postby brooksby » 25 Sep 2019, 3:16pm

mjr wrote:
brooksby wrote:OK, thanks for that. I wouldn't want to get pulled over for having a light on the left side of my handlebars! :D

That's highly unlikely. It's far more likely that some weasel might try to use it as an excuse for knocking you off during a failed close pass because they thought your lights meant you were two feet further left.


Good point. Maybe I'll move it... :roll:

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Re: Front light positition

Postby Brucey » 25 Sep 2019, 8:28pm

mjr wrote:
Brucey wrote:FWIW most motorcyclists live in fear of being SMIDSY'd and they are lit up like a christmas tree.

And being lit up like a tree doesn't seem to be working for them, so I'm not sure that's a great argument!


my point is that most motorists are looking out for cars not two wheelers of any kind, and making yourself less visible by having a lamp that can be obscured from some angles isn't going to help matters one bit.

Brucey wrote: Riding around with only a fork-mounted lamp that is definitely obscured from certain angles is not going to improve your life expectancy.

It'll certainly improve it more than riding around without any lights! Of course, don't mount it high enough that the top of the rim will block the lamp over a wide area of other road user head heights, but the obscuring of a lamp mounted low on the fork will be minimal and fairly far ahead of the bike. Oh and I just remembered: for the above to apply, it's important that the illuminated surface area (lens or reflector, depending on design) is wider than the tyre!


not quite as simple as that; the reflector/lens is usually designed to throw a beam of some kind and there is no guarantee that light thrown from the periphery of the lens/reflector is going to be thrown anywhere other than forwards. In many cases the light that emerges at an angle to the main beam (and renders you visible at an angle from side turnings) only comes from a small proportion of the light. You can gauge if this is the case by looking at the shadow that is cast by the front wheel; a well defined shadow essentially means a small effective emitter. Anyone within the shadow area won't be able to see the light. If the light emits strongly at an angle over the full diameter of a large lens then there would be no real shadow. IME this never happens, and worse yet deep aero section rims and fatter tyres mean the rim/tyre is more than ever capable of obscuring a fork mounted light.

If you use a fork boss for a lamp there is usually a shadow cast at an angle of twenty or thirty degrees to one side. This corresponds nicely with a 'constant bearing' (as described previously) onto a vehicle that is going towards/pulling out of a side junction at 5-10mph whilst you are doing 10-20 mph down the main road. This is exactly how accidents happen, and (as axle knutt suggests) a claim of 'SMIDSY' might be accurate in this case. Motorists already have their windscreen pillars to obscure you from view, they and other road users don't need an effectively invisible light on your bike too.

My suggestion is that if you use a lamp like this, add a flashing LED or something higher up, that can be seen; it might save your life. If you use a fork mounted lamp only, from choice, then IMHO you are taking a pointless risk.

cheers
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Re: Front light positition

Postby pwa » 25 Sep 2019, 8:41pm

I have this arrangement on a bike, with a B&M dyno light mounted directly in front of the handlebar stem. It works really well for me with the cables I have to direct the beam between, but others may find their cables get in the way.

https://www.sjscycles.co.uk/lighting-sp ... g-bracket/

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Mick F
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Re: Front light positition

Postby Mick F » 25 Sep 2019, 8:47pm

Back in the day when I had a RH fork mounted front light, it was well before LED lights came on the scene.

Back then, my front light was maybe 3" diameter and threw out plenty light sideways as well as front-wards. Batteries as well as dynamo.
These days, lights are brighter but also smaller diameter and throw out a more pencil coherent lazer-like beam in comparison to the general incandescent spread of a Xenon or Halogen bulb through a big lens more like a flood light.

In all the years I used a fork blade mounted front light, I had no issues whatsoever of cars and people seeing me from the left. Loasda spread of light. These days, there's too much of a cut-off and focus involved.

Bring back the big broad flood lights and do away with the small but powerful LED focused pencils.
Mick F. Cornwall

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Re: Front light positition

Postby pwa » 25 Sep 2019, 8:51pm

I tried mounting a light on the right fork but I couldn't live with the considerable wheel shadow. It seemed to me to be a poor place to put a light if you don't want to be looking at shadows made by your own bike.

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Re: Front light positition

Postby Brucey » 25 Sep 2019, 9:01pm

BITD I had a 3" diameter lamp with a parabolic reflector and a tungsten bulb in it.

When mounted on the fork boss this lamp threw a very crisp shadow of the wheel rim/tyre into the hedge/eyes of other road users and rendered the lamp almost invisible from certain angles.

The main reason I didn't like the setup was that, on country lanes, the shadow thus cast was very distracting. But it was also ( quite pointlessly) unsafe, too.

I soon converted to a fork crown mount and it was much better. In fact when that frame was refinished, I took the fork boss off altogether, judging it to be both pointless and dangerous.

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Re: Front light positition

Postby Mick F » 25 Sep 2019, 9:18pm

I don't remember shadow issues at all.
Many thousands of miles commuting in the dark.

No doubt there was a shadow, but it mattered not a jot.
Mick F. Cornwall

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Re: Front light positition

Postby Debs » 26 Sep 2019, 2:50am

Yonks ago i knew someone who's light-bracket on a folk leg came loose; the light and bracket swivelled around into spokes and jammed the wheel, he went over the handlebars face first into the road knocking out a few teeth.

Seems odd that bicycle design has not incorporated a 'universal' light attachment on the head-tube, seems like a good place to put a light.

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Tigerbiten
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Re: Front light positition

Postby Tigerbiten » 26 Sep 2019, 5:12am

Debs wrote:Seems odd that bicycle design has not incorporated a 'universal' light attachment on the head-tube, seems like a good place to put a light.

The head-tube doesn't rotate with the forks.
So on a corner the light tends to illuminates the hedge straight ahead and not the road surface around the bend.
So any light on there would need to put out a beam which is a lot wider to compensate.
But the wider the beam, the less light is thrown straight ahead to show you where you're going.
You could probably get away with it with modern lights simply because they're a lot more powerful.
But go back to the era of the never-ready battery lights and you just wouldn't have seen where you were going.

I can only get away with lights fixed to the frame on my recumbent trike only by using two good lights, one pointing slightly left and the other slightly right to spread the light cone wider.
With only one light it's not unknown for me to start around a left hand curve and suddenly find/hit a pothole which was not in the light cone.

Luck .......... :D