Lights - flashing or constant

by paulfg42   October 21, 2011  

I usually have my lights on constant. However, I've noticed quite a lot of cyclists use flashing lights.

Which do you prefer and why?

27 user comments

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Both for me, i have 2 front and 2 rear, one of each on constant and one on strobing, keeps me seen, as long as your have the strobing ones points a bit lower than normal, it seems to work fine as your not blinding anyone and your more visible

Gkam84's picture

posted by Gkam84 [9369 posts]
21st October 2011 - 21:09


I use flashing in urban areas and constant in the countryside

posted by mrkeith119 [88 posts]
21st October 2011 - 21:11


flashing for me.drivers seem to notice them more

posted by mpt68 [107 posts]
21st October 2011 - 22:03


Flashing at dusk/dawn and constant at night. When your lights are flashing they are off just as much as they are on. This makes it more difficult for other road users to gauge your actual position at night and its just distracting. If you can have one good solid light and one little blinker that's a good move but never use flashing alone at night.

Napalmhaze's picture

posted by Napalmhaze [81 posts]
21st October 2011 - 22:15


Flashing on the back and constant on the front has always been my preferred option but I've been running the Exposure Flare/Flash combo since last winter which lets you have your cake and eat it because the flashing mode is effectively both flashing and constant at the same time with the constant bit knocked back a bit so that it doesn't eat battery life - it does seem to be very effective as an attention grabber partiuclarly at the rear.

Tony Farrelly's picture

posted by Tony Farrelly [4201 posts]
21st October 2011 - 22:15


I did read somewhere that while flashing will be noticed more, constant lights are easier for others to judge distance. On that basis I use both for front and rear: a fenix on constant and a Knog frog flashing while I have a Cateye TL-LD1100 at the back that does both.

TheHatter's picture

posted by TheHatter [811 posts]
22nd October 2011 - 19:59


good point napalmhaze, i had not thought of the distance at night, but i am +1 with tony_farelly on the flash and flare having cake an eat it.

roadie come mountain biker come single speeder and back again

posted by cborrman [84 posts]
24th October 2011 - 17:42

1 Like

Ordered the Exposure Flare rear light and will flash and be constant simultaneously!

posted by paulfg42 [395 posts]
24th October 2011 - 18:44


Constant all the time, with one of my Flares on pulse for battery conservation. I can't see the point of having a light which is actually OFF for part of its cycle..surely the point is to be visible at all times. Unless you're using your bike as some kind of mobile disco.

posted by andyp [1371 posts]
25th October 2011 - 12:10


I usually have at least one light flashing when it's a bit dismal outside, moving on to one front flashing and one front constant, and if it's really dark then both front lights on constant @ maximum output.

Lights in use are usually a pair of RSP asteri 3's, rarely I need to use anything brighter than those.

the_mikey's picture

posted by the_mikey [155 posts]
25th October 2011 - 18:39


On the rear Red-Eye constant and a Hope District on strobe, Up front Exposure Joystick and Toro, the Joystick is constantly on flash as it powers the red eye while the Toro is on flash in town and constant out on the open road.

Use this set up year round as it seems to make a difference even in daylight

Twitter - @StuKerton

stuke's picture

posted by stuke [356 posts]
25th October 2011 - 23:30


flashing, same principal as a lighthouse more noticeable over a distance Cool

andrew miners's picture

posted by andrew miners [46 posts]
26th October 2011 - 10:44



I really noticed what a difference it makes cycling behind the wife who was using constant. Nowhere near as visible imo

mr-andrew's picture

posted by mr-andrew [303 posts]
26th October 2011 - 10:49

1 Like

I mostly use a hub-dynamos (because I like to switch both lights on whenever, e.g. for dark underpasses or when low sun dazzles following drivers) so my rearlight is steady, since that's the only game in dynamotown.

But when I have to ride a toy-bike in the dark, I set the rear battery lamp to flash.

My thinking is that the main point of a rearlamp on a bike is to grab attention, and it's plain obvious that flashing does that better, otherwise turn indicators, emergency vehicles, road works, etc. wouldn't do that.

And a bike is the only vehicle allowed a flashing red light, so it immediately says "bike in front". That identification is crucial, since the driver is going to have to brake or overtake pretty soon whatever.

Gauging the distance to that bike comes last of all and there are lots of other visual clues to do that better than binocular vision on a little red spot.

Contrary to popular belief, people do not become invisible the moment they straddle a bike. And cars have headlights that even on dip are perfectly adequate for a driver to see how big and hence how far away a cyclist is - once his attention has been grabbed to actually look in that direction.

I do also drive by the way, at least once a week, and have never had any difficulty seeing a cyclist or a pedestrian that I'm actually looking at. The trouble on our roads is that so few drivers are really looking out for people. I think I've talked myself into adding a battery flasher to my dyno bikes!


Crankwinder's picture

posted by Crankwinder [17 posts]
26th October 2011 - 11:47


'And a bike is the only vehicle allowed a flashing red light, so it immediately says "bike in front". That identification is crucial, since the driver is going to have to brake or overtake pretty soon whatever. '

that one is such a comedy argument. Presumably said driver would just drive straight into the back of anything showing a constant light, because they wouldn't need to brake or overtake? Wink

posted by andyp [1371 posts]
26th October 2011 - 12:51


I use a single constant at the front and a single flashing at the rear - maybe I should have more. Good thing LED lights is you can dress your bike up like a Christmas tree and they still weigh less than the old skool things I grew up with as a nipper and had on my much missed Falcon Black Diamond - nostalgia, who needs it?


posted by OldRidgeback [2586 posts]
26th October 2011 - 21:01


Personally I go for a good light to cover seeing and being seen on the front then at the rear a bright, fixed light attached to the bike and flashing B&M Topfire lights in the helmet vents. The Topfire lights aren't REALLY bright but enough just to draw attention to you. After buying a rear light from Bike24 I thought it was odd that it didnt have a flashing function but it turns out in Germany (who have some of the strictest cycle light regulations in the World) that flashing rear lights are illegal!

posted by mypeloton [5 posts]
26th October 2011 - 21:05


The emergency services use flashing lights to attract the attention of motorists. If it works for them, it's good enough for me.

posted by FMOAB [262 posts]
27th October 2011 - 23:03

1 Like

paulfg42 wrote:
Ordered the Exposure Flare rear light and will flash and be constant simultaneously!

That little baby sure is bright!

posted by paulfg42 [395 posts]
28th October 2011 - 19:57

1 Like

3 on back (one flashing) 3 on front all constant. Personally I hate cycling towards a very bright flashing white light. But must agree, a flashing red draws your attention to the cyclist in front. The Highway Code is quite specific regards lights on a bike regards intensity etc. And plod if he was going totally by the book would be quite happy to slap a fp on you if there wasn't a constant light. Though, most don't give a rip, just as long as you are lit Smile Mind you, they don't give a rip if you have no lights, at least up where I stay this seems to be the case.

giff77's picture

posted by giff77 [1187 posts]
29th October 2011 - 12:39

1 Like

I use two up front, one on constant and one on strobe. On the rear I have 4, 3 on flash and one main on constant.

Let's hope this keeps Kirky safe!

posted by Kirky [3 posts]
10th November 2011 - 19:41

1 Like

There's a reason emergency vehicles have flashing lights - I always have rear on flash. I don't care about the British Standard as it was written by a committee whose primary interests are the sale of batteries and lights, not whether it is the most visible or not.

Make mine an Italian with Campagnolo on the side

posted by monty dog [433 posts]
11th November 2011 - 10:26


Super bright front flashers are in my opinion dangerous. Especially to other cyclists. When I'm cycling during rush hour, the most distracting thing I find is other cyclists lights. They don't make you more visible, they make you annoying, distracting and difficult to actually gauge your position.

If you must have a flasher to compliment your steady lights at night then use something like the Knog Frog or other such emergency lights.

While I'm at it, this lumens race has gotten out of hand. Thank you magicshine et al. These beams are not designed for the road and are blinding. That makes you as visible as a welder, yeah sure I can see you, but its burning my eyes out. I shouted at several people on the cycle track recently for having their uber-lumen lights aimed right at my face.

Napalmhaze's picture

posted by Napalmhaze [81 posts]
11th November 2011 - 11:20


You can't have enough lights (mix of flashing and constant). So far Kirky and Giff77 both have a total of 6.

For the record I use 2 on the front (one flashing, one constant); 2 on my helmet; and 2 on the rear (one flashing, one constant). Come to think of it, I use the Aldi hi viz ankle straps with red LEDS in, so if I was particularly conscientious I would have 8.

Anyone use more?


posted by arrieredupeleton [587 posts]
11th November 2011 - 11:54

1 Like

I'd suggest that for the rear a steady plus a small(er) flasher is ideal, particularly if the flasher can be mounted high up (rucksack/helmet) so the rider is visible in a line of traffic. If used at the same level I'm not sure it would add much benefit over just the steady light. Flash-only in busy town traffic risks being missed except on quieter routes.

At the front the best option may vary depending whether you are on streetlit or unlit roads. I'd suggest that a wide beam or a light with good side spill plus a flasher is useful in town, whereas out in the countryside you want adequate illumination on the path in front of you. A secondary consequence of this will be a steady, bright light source for oncoming traffic to see clearly.

For time trials a flashing rear light is the best option. Cateye LD600 and RSP Astrum are bright enough to stand out well in daylight, while on the front my diminutive Electron Backupz unit helps on dull days and where there is some tree cover. A time triallist will have a considerably smaller profile - both front and rear - than the typical sit-up-and-beg commuter.

Simon E's picture

posted by Simon E [2419 posts]
11th November 2011 - 16:37


exposure maxxd on front, dinotte 300r on rear. NEVER EVER use flash. I'd rather be mistaken for a slow motorcycle than a fast cyclist due to most motorist's neuroses around cyclists, which frequently endanger me. Ive never understood why cyclists feel the need to be positively identified as such???duhhh??

posted by wyadvd [126 posts]
16th November 2011 - 22:08


interesting article re flashing lights. An americanstudy has clearly shown that stationary emergency vehicles covered in flashing lights are more likely to be run into by drunk and distracted drivers than just steady red lights alone (especially at night and in fog)

posted by wyadvd [126 posts]
20th November 2011 - 22:57