# The best rear light position



## johnnyb47 (3 Apr 2017)

Hi again.
I was wondering where do you think the best position a rear light should be placed on your bike. I personally think on your trusty helmet. As a high mileage driver i often notice rear helmet lights long before seat post / bike frame mounted lights. It think it's because they are more visible being that their higher up and can be seen over a few cars back sitting behind the cyclist. Also and which is more important is that a helmet light appears to move more unpredictably. A cyclists head is constantly turning from side to side looking for hazards as well as swaying from side to side when he/ she is peddling hard..This obviously makes the helmet light move around in an unpredictable manor which catches the attention of the dozy motorist ( "ie me :-).
A helmet light will catch your eye better as it momentarily flashes it's LEDs in its strongest focal point at you grabbing your attention. As there higher up they also don't blend in with other road users lights ,as a seat post light is nearly the same level as most car lights and don't stand out as much..


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## Drago (3 Apr 2017)

Strictly speaking a helmet mounted light doesn't meet the lighting regs, so only have one up there as a supplementary light.


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## johnnyb47 (3 Apr 2017)

That's a good point buddy. That didn't even enter my head that they may be illegal


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## Drago (3 Apr 2017)

Probably no one cares, until you get hit and their smart arse lawyer makes a big deal out of it.


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## fossyant (3 Apr 2017)

You need more than one anyway. 

You need a good light on the bike, and maybe a light on the helmet/hair net for the non helmet folks... 

Helmet isn't good, as you are turning to look, so the light's intensity varies, and as a driver, you do need at least one fixed point to see. A sole helmet light will get you right in bother if you get in an accident, as the modern legal eagles will try and pull any injury compensation claim to bits if you did not conform to any standard. Been at the sharp end of it a few times.


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## fossyant (3 Apr 2017)

Cross posts with Drago...


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## Cuchilo (3 Apr 2017)

You cant miss this bad boy ! https://four4th.co.uk/products/lights/scorpion/ Unless of course you are looking at your phone rather than the road .


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## Will Spin (3 Apr 2017)

I used to commute by car for 38 miles early in the morning on country lanes and single lane main roads. Cyclists with single helmet mounted rear lights on dark lanes once or twice got me momentarily confused as they seemed further away than they actually were. This is because the light appears higher up in the windscreen, about where you would expect to see a car rear light some distance away.


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## lutonloony (3 Apr 2017)

Seatpost and rucksack for me, gives the motorist two targets to home in on


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## Milkfloat (3 Apr 2017)

Cuchilo said:


> You cant miss this bad boy ! https://four4th.co.uk/products/lights/scorpion/ Unless of course you are looking at your phone rather than the road .




Or the rider has a long jacket.


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## Cuchilo (3 Apr 2017)

Milkfloat said:


> Or the rider has a long jacket.


Or wearing a kilt .


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## Slick (3 Apr 2017)

I use a pulsing rear light that emits a side light set on my seat post at the exact same height as my car. I chose that location, as I assumed that if Jaguar engineers thought that it was a good height, who was I to argue.


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## winjim (3 Apr 2017)

Slick said:


> I use a pulsing rear light that emits a side light set on my seat post at the exact same height as my car. I chose that location, as I assumed that if Jaguar engineers thought that it was a good height, who was I to argue.


Exactly. Put your rear light at rear light height.


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## Reynard (3 Apr 2017)

Got one on my seatpost and one on my lid.

Though have to agree somewhat with OP - when I'm driving, I find cyclists are more visible when sporting seatpost *and* lid lights.


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## Old jon (3 Apr 2017)

One on the seat stay, one on the saddlebag. Very gently, I cringe when I see anything fastened to a helmet. All that expensive impact absorbing headgear and someone fastens a small hard object to it. About the size of the business end of a hammer. . .


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## classic33 (3 Apr 2017)

johnnyb47 said:


> Hi again.
> I was wondering where do you think the best position a rear light should be placed on your bike. I personally think on your trusty helmet. As a high mileage driver i often notice rear helmet lights long before seat post / bike frame mounted lights. It think it's because they are more visible being that their higher up and can be seen over a few cars back sitting behind the cyclist. Also and which is more important is that a helmet light appears to move more unpredictably. A cyclists head is constantly turning from side to side looking for hazards as well as swaying from side to side when he/ she is peddling hard..This obviously makes the helmet light move around in an unpredictable manor which catches the attention of the dozy motorist ( "ie me :-).
> A helmet light will catch your eye better as it momentarily flashes it's LEDs in its strongest focal point at you grabbing your attention. As there higher up they also don't blend in with other road users lights ,as a seat post light is nearly the same level as most car lights and don't stand out as much..


Higher up can also equate to closer to for some drivers. 
On some of the wilder nights, I've used one of these in the mesh pocket of the rucksack. Painted over in a clear red paint.


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## Accy cyclist (3 Apr 2017)

If it's a weak light have it facing horizontally. If it's quite powerful have it facing slightly down.. Motorists are like moths,drawn to bright lights. Meaning they could land on you rather than give you a wide berth.


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## KnackeredBike (4 Apr 2017)

As low as possible whilst still being visible will make you seem nearer to the motorist. Well worth doing as if you read studies motorists typically notice cyclists at 150m away or less so appearing nearer is a big advantage.

It's the Father Dougal thing, things near to the horizon seem further away to us easily tricked humans. If you want to see how powerful this is look at the moon next time it's near to the horizon, it seems huge compared to when it is in the sky even though of course it is always near enough the same size.


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## steveindenmark (4 Apr 2017)

I have 2 on the back of the bike and I stitched a piece of webbing high up on my vis vest to slot a Smart light into. I think it is important to have a light higher up to be seen easier in traffic.


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## ufkacbln (4 Apr 2017)

Helmet lights also move out of motorists line of vision if you perform a shoulder check or look down (how much depends upon design)

As above, if you wish to be "legal" there are a set of heights and positions you are required you comply with, all of which are on the bike

However as a general rule if it is visible, unobscured by clothing, saddlebags, panniers etc and not blinding following roadusers you will not be stopped


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## cubey (4 Apr 2017)

Layzene strip light pro, the dogs b.................s, but equally important is your clothing, and a Proviz jacket is about as bright as they get.


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## Jody (4 Apr 2017)

One on the seatpost and one on your lid. Seatpost to have some none flashing LED's also.


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## GlenBen (4 Apr 2017)

I read once about a cyclist who fell off, went the other direction to his bike and got hit by the car that was swerving to try and avoid the light that was on the bike. 

I do think the seatpost is the best for visibility, but that story does make me wonder.


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## Jody (4 Apr 2017)

Old jon said:


> One on the seat stay, one on the saddlebag. Very gently, I cringe when I see anything fastened to a helmet. All that expensive impact absorbing headgear and someone fastens a small hard object to it. About the size of the business end of a hammer. . .



You hit your head on all sorts of shapes anyway so a small flat light attached to the base of a lid is going to make little difference to safety.


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## Aravis (4 Apr 2017)

I always use a rack-top bag, so the conventional seat post position is unavailable, and I struggled with this for a while. I never wear a helmet, so there's no temptation in that direction.

My solution, which seems to work perfectly, is to use two lengths of plastic overflow pipe, attached either side of the rack with a bungee:


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## mjr (4 Apr 2017)

Aravis said:


> View attachment 345595


Get one of the lights that replaces the rear rack reflector.

Second best is a light on the right hand seat stay. Good rear visibility, plus easy to see to check it's still on.

Third best is back of the mudguard.

Seat post is poor. Too close to the centre of the bike, too high for ideal.

Helmet light is worse. Points the wrong way frequently if you're looking around and contrary to most helmet instructions.


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## Profpointy (4 Apr 2017)

seat post is questionable is it's quite likely to be under your coat, or at least you'll be worrying it's under your coat. I think the back of the pannier rack is best. Helmet - whilst I don't wear one myself, I'd not be too worried about increased risk on a crash providing light was plastic as it'd likely be biffed off or smashed in an impact. Used to wear a front-facing elastic headtorch as well as / instead of a front light


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## Tin Pot (4 Apr 2017)

johnnyb47 said:


> Hi again.
> I was wondering where do you think the best position a rear light should be placed on your bike. I personally think on your trusty helmet. As a high mileage driver i often notice rear helmet lights long before seat post / bike frame mounted lights. It think it's because they are more visible being that their higher up and can be seen over a few cars back sitting behind the cyclist. Also and which is more important is that a helmet light appears to move more unpredictably. A cyclists head is constantly turning from side to side looking for hazards as well as swaying from side to side when he/ she is peddling hard..This obviously makes the helmet light move around in an unpredictable manor which catches the attention of the dozy motorist ( "ie me :-).
> A helmet light will catch your eye better as it momentarily flashes it's LEDs in its strongest focal point at you grabbing your attention. As there higher up they also don't blend in with other road users lights ,as a seat post light is nearly the same level as most car lights and don't stand out as much..



Lights make things less stressful for attentive drivers. But they'd see you anyway.

It matters not what you do with your lights for the drivers that would kill you.


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## Tin Pot (4 Apr 2017)

Profpointy said:


> seat post is questionable is it's quite likely to be under your coat, or at least you'll be worrying it's under your coat. I think the back of the pannier rack is best. Helmet - whilst I don't wear one myself, I'd not be too worried about increased risk on a crash providing light was plastic as it'd likely be biffed off or smashed in an impact. Used to wear a front-facing elastic headtorch as well as / instead of a front light



...Coat???


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## Arjimlad (4 Apr 2017)

Favourite commuting helmet is a Lidl lid which came with an onboard LED light on the rear, three settings, steady, flashing or disco mode, plus I have 2 bright rear lights on the back of the seatpost, if one conks out then the other should hold the fort.

I once got to the end of a fast & long unlit country road & found that my (cheapo) rear light had rattled itself to bits & stopped working. Not a happy bunny although the reflectives would have made be perfectly visible to any attentive driver.


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## Rooster1 (4 Apr 2017)

How about built in lights

http://www.theverge.com/circuitbrea...on-bicycles-smart-bike-gps-lights-kickstarter


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## glasgowcyclist (4 Apr 2017)

My dynamo setup includes a rear light built in to the rack. I've driven behind it and it's very effective.


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## tommaguzzi (4 Apr 2017)

First of all i would have to own a "trusty" helmet which i dont. I also believe body mounted lights arnt strictly legal anyway. If you turn your head they are nolonger visible.
Also ask Michael Schumacher if mounting hardware to your helmet is a good idea. The camera he had on his is what caused his brain damage after it pushed through his helmet and into his skull when his head hit the tree
My light is on the seat toolbag and now they are able to flash i don't think there is a visibility problem.


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## Drago (4 Apr 2017)

tommaguzzi said:


> Also ask Michael Schumacher if mounting hardware to your helmet is a good idea...



Uh-oh, that's torn it!


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## glasgowcyclist (4 Apr 2017)

tommaguzzi said:


> Also ask Michael Schumacher if mounting hardware to your helmet is a good idea. The camera he had on his is what caused his brain damage after it pushed through his helmet



I believe that's unsupported guessing and hasn't been established.


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## Jody (4 Apr 2017)

mjr said:


> Seat post is poor. Too close to the centre of the bike, too high for ideal..



How is it too high for ideal when it is about on level with a cars rear lights?


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## Smithbat (4 Apr 2017)

cubey said:


> Layzene strip light pro, the dogs b.................s, but equally important is your clothing, and a Proviz jacket is about as bright as they get.



I love these jackets, but sadly like most other cycle clothing manufacturers, they believe that us plus size cyclists do not exist, therefore are not worth providing the larger sizes.

I have mine on my rack at the back as I usually have a top bag on it so the seat post is obscured.


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## mjr (4 Apr 2017)

Jody said:


> How is it too high for ideal when it is about on level with a cars rear lights?



As explained earlier:


KnackeredBike said:


> As low as possible whilst still being visible will make you seem nearer to the motorist. Well worth doing as if you read studies motorists typically notice cyclists at 150m away or less so appearing nearer is a big advantage.
> 
> It's the Father Dougal thing, things near to the horizon seem further away to us easily tricked humans. If you want to see how powerful this is look at the moon next time it's near to the horizon, it seems huge compared to when it is in the sky even though of course it is always near enough the same size.


There is a legal minimum height but I think it's high enough that you'd have to do something daft like put it on the mudflap to fall foul on a full-size bike.

I feel car light height is irrelevant unless you're on a tricycle because you can't mimic the spacing. Motorcycle light height is part of why a large-lit-area light under the back of the rear rack is best.


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## TheDoctor (4 Apr 2017)

One on the rack, one on the seatpost / saddlebag / rear pannier / rear pocket for me.


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## Jody (4 Apr 2017)

@mjr Can't really change the position of mine but it makes sense I suppose.


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## MontyVeda (4 Apr 2017)

Seat post _and_ saddle bag for me. Although i only tend to run both when it's raining or i'm on unlit roads.


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## glasgowcyclist (4 Apr 2017)

As well as my rack light, I have: a cob light on a saddle-mount, just above my Fly6; a magicshine rear fixed to the offside rear where the chain stay meets the seat stay, which I use in very poor visibility just like a fog light; and to give a better impression of width, I have a fibre-flare attached vertically to the outside of each of my panniers.

I don't use all of these at the same time but vary them as conditions dictate.


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## RoubaixCube (4 Apr 2017)

Smithbat said:


> I love these jackets, but sadly like most other cycle clothing manufacturers, they believe that us plus size cyclists do not exist, therefore are not worth providing the larger sizes.
> 
> I have mine on my rack at the back as I usually have a top bag on it so the seat post is obscured.



I remember i tried some of their Jackets/Gilets when Proviz first started selling their products even though they had a very limited range, Even though the sizes were in the 'bigger' ranges, they still felt about two sizes too small and i sent them back. They charged me for returns despite a big flash banner saying "free UK returns" but after consulting their CC they refunded me postage via paypal.

Nice Jackets though, Just shame about the sizing/sizes

-----

Ive always tried to have a blinker on the back of my helmet (Blinker - not a blinder!) as It widens the range or angles at which i can be seen

Heres how I have my Kask helmet set up, pretty straight forward and easy





















Its a Topeak Redlite Aero USB so its not the brightest but it gives 180' visibility so even if i turn my head to check whats coming up behind me, you can still see it. The light fit just perfectly as its the right length/girth to mount flush against the actual helmet and it uses the strap thing at the back of the helmet (pictured...)






To keep the light in line with the rest of the helmet. Theres supposed to be a small section at the back of the topeak like where you can slide a slab of rubber to help hold it in place so it doesnt wobble about when attaching to a seatpost but by not installing it, the back of the helmet is 'countersunk' into the back of the light.

On the days where i do finish work pretty late in the evening, seeing another cyclist with a blinker on the back of his or her helmet definitely makes them more noticeable in my eyes at least.

I measured the back of the helmet and looked around for ages for something that would just slot in and look as if it was part of the helmet. (you need a light thats 15cm, most similar lights are 16-17cm so the light doesnt sit flush with the rest of the helmet at leaves a small gap because of the angling of the helmet)

I would prefer it was a little more low profile as it sticks out just a little too much for my taste.

Sometimes i have big Tescos or Sainsburys lorries on their way to drop supplies off at their stores roll up behind me. I doubt the driver would of been able to see the light thats attached to my seatpost from up that high so its always peice of mind knowing they know im there.


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## mjr (4 Apr 2017)

Jody said:


> @mjr Can't really change the position of mine but it makes sense I suppose.


Oh well - it's still better than nothing!



RoubaixCube said:


> Sometimes i have big Tescos or Sainsburys lorries on their way to drop supplies off at their stores roll up behind me. I doubt the driver would of been able to see the light thats attached to my seatpost from up that high so its always peice of mind knowing they know im there.


The driver should be able to see you. If they're so close that they can't see a light on your seatpost, or if they can't see a light at all, they farking well shouldn't be driving, let alone holding a lorry licence.


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## Jody (4 Apr 2017)

User said:


> All of you who advocate helmet or rucksack mounting, have you had someone else ride behind you and give feedback on how effective the placement is? I see people with a helmet mounted light obscured by a rucksack, or a rucksack mounted light pointing skywards.



What if you wear one on a helmet without a rucksack?


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## Jody (4 Apr 2017)

User said:


> It might be a good idea to check that it does actually point in the right direction.



No need as I look forward the vast majority of time when cycling.


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## RoubaixCube (4 Apr 2017)

mjr said:


> Oh well - it's still better than nothing!
> 
> 
> The driver should be able to see you. If they're so close that they can't see a light on your seatpost, or if they can't see a light at all, they farking well shouldn't be driving, let alone holding a lorry licence.



Im hardly going to stop every lorry driver behind me and ask if they saw me or to check their license though. Its not my job to and id rather they see me then not see me regardless of how close they are. Should they be that close? of course not. But there are many drivers that pass cyclists close enough to tickle them every day and not a lot seems to get done about them.


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## youngoldbloke (4 Apr 2017)

Surprised no one has quoted the CTC:

_*"Rear Lamp*

One is required, to show a red light, positioned centrally or offside, between 350mm and 1500mm from the ground, at or near the rear, aligned towards and visible from behind. If capable of emitting a steady light it must be marked as conforming to BS3648, or BS6102/3, or an equivalent EC standard.


If capable of emitting only a flashing light, it must emit at least 4 candela."_


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## ianrauk (4 Apr 2017)

Jody said:


> No need as I look forward the vast majority of time when cycling.




I think you would be surprised at how much you actually don't.


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## Jody (4 Apr 2017)

ianrauk said:


> I think you would be surprised at how much you actually don't.



But when the light emitted is 35 degrees from centre then a fair amount of tilt can still be acceptable and the light be seen. Plus its only a secondry light


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## ianrauk (4 Apr 2017)

Jody said:


> Plus its only a secondry light



That's fair enough.

Being in London I do see a fair few cycle commuters with just the one light on the back of their plastic hat and more often then not, the light is either obscured by a back pack or it's tilted/facing at a wrong angle.


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## Archeress (4 Apr 2017)

Because I'm commuting in and out of University, I have racks on both bikes to carry my laptop pannier and an ortlieb. I find a Smart Lunar on the reflector mount of the rack is a really good place as it's right at the back of the bike and hard to miss. I also have a Cateye Volt 50 mounted on the saddle rails so it's a little higher. Mind you, I didn't appreciate quite how bright the Cateye was when I bought it, I don't think I'll use it if I go out with the Fridays in May, just the Smart Lunar. For the Cateye, think about rear fog lights, but a bit brighter again, but not quite as bright as a laser pointer.

Hugs
Archeress x


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## ufkacbln (4 Apr 2017)

youngoldbloke said:


> Surprised no one has quoted the CTC:
> 
> _*"Rear Lamp*
> 
> ...




Lighting is complex, there was a Cateye light some time ago with BS 6102/3 validation

Unfortunately it was for the reflector part, not the full light


The other problem is that there are lights that satisfy the Road Vehicle Lighting Regulations that are not BS6102/3 compatible, and vice-versa

The practical solution for most lighting and the approach that I tend to use is a "legal" light for insurance reasons and. "Backup light" that actually works


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## MontyVeda (4 Apr 2017)

User said:


> All of you who advocate helmet or rucksack mounting, have you had someone else ride behind you and give feedback on how effective the placement is? I see people with a helmet mounted light obscured by a rucksack, or a rucksack mounted light pointing skywards.


Same goes for saddle bag lights... I've seen a handful of folk who's overcoat completely obscures it. I've also seen the rucksack issue too.


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## youngoldbloke (4 Apr 2017)

Cunobelin said:


> Lighting is complex, there was a Cateye light some time ago with BS 6102/3 validation
> 
> Unfortunately it was for the reflector part, not the full light
> 
> ...



Agreed, but It was the height quoted that interested me - between 350 and 1500mm - about 14" and 5 feet (!). Have to be a rather large bike to have a light at 5 feet, assuming that this refers to lights fixed to the bike itself, perhaps this is to cover 'ordinary' riders?


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## ufkacbln (4 Apr 2017)

youngoldbloke said:


> Agreed, but It was the height quoted that interested me - between 350 and 1500mm - about 14" and 5 feet (!). Have to be a rather large bike to have a light at 5 feet, assuming that this refers to lights fixed to the bike itself, perhaps this is to cover 'ordinary' riders?



You think YOU have problems!

Try riding a recumbent trike!


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## classic33 (4 Apr 2017)

User said:


> All of you who advocate helmet or rucksack mounting, have you had someone else ride behind you and give feedback on how effective the placement is? I see people with a helmet mounted light obscured by a rucksack, or a rucksack mounted light pointing skywards.


On the nights I've used one carried in the mesh pocket of the rucksack, I've been told they didn't know what the light was, or that it wasn't legal as it was flashing.

Response was that they'd seen it and me. Also it was a "be seen light" attached to the person, not the bike and entirely legal.


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## mjr (4 Apr 2017)

RoubaixCube said:


> Its not my job to and id rather they see me then not see me regardless of how close they are. Should they be that close? of course not.


If they're that close, should your first thought be "I'm glad my light is visible to them"? Of course not. Probably something like "get me the fark out of here" would be more useful.


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