Rear light with dropper post

p3eps

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Dec 14, 2019
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I generally don't go out riding in the dark, but have been going out in the evenings since it's nice weather and light nights. I have to wait until the kids are in bed, so I'm not getting out until after 19.30.

The last few rides, I've been on my way home, and having to go along pavements as daylight is fading.
It's never "dark", but I probably should be a bit more visible... so I'm looking for some small blinky lights!

Obviously I can't attach a light to my seatpost, as it goes up and down. My post is slammed as much as it can, so there's nothing left at the bottom to attach a light to.
Can anyone suggest a small rear light that'll attach to the seat rails? Doesn't have to be anything super bright or fancy... just something that'll keep me visible as the light fades.
 

R120

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Apr 13, 2018
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Though I would watch out for your tyre hitting any light with the seat slammed. Helmet mounted light might be an option?
 

B1rdie

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Feb 14, 2019
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Decathlon has some tinny usb rechargeable that are easy to attach anywhere, and cheap.
 

simonk

SLayer ?
Jan 27, 2020
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Exeter
The Moon Nebula has a saddle rail mount included. If you have any seatpost showing though I’d go for the Lezyne KTV Pro 75. Its the only rear light I haven’t managed to kill so far due to water ingress.
 

RedTed

Member
Oct 1, 2019
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Sheffield
Another vote for Moon Nebula, very bright, lots
of modes and can be seen from side on. The mounting on the seat post is very secure.
 

Gary

Old Tartan Bollocks
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No.
and yes. I get where you're going with that question as it does mean you need to be able to clean out the housing/threads to fit the light mid ride or pay attention to cleaning it after rides where you had no light fitted.
it wouldn't be difficult to make a cover. - A coke bottle top fits over the housing nicely (But I'm not sure how well it'd stay in place on a rough ride)
it also wouldn't be difficult to just remove the ziptied mount when not needed and fit when it is. it's a 2 min job.

also beware of Ebay/Amazon/AliX sellers selling copies of these lights. I have 2. and one of them doesn't quite work on "Auto" mode the way it should.
 

p3eps

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Thanks for all the suggestions.
I’ll have a proper look tomorrow and check out some reviews.
I do have the AXS collar, and probably an inch and a half of frame that I could probably attach a post mount type light.
 

Apr 26, 2020
109
80
Out west
Get a cheap under seat saddle bag with a mounting strap for a light. Keep the light in the bag on the trail. Itll break or fall off if you ride off road with it attached
 
Last edited:

aarfeldt

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May 25, 2019
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I have the same issue....sometimes it's a bit dark, when going to the trail.
I have this small Topeak on the side of my helmet....dosent disturb and it's allways with me.

topeak_headlux.png
 

Darren

Active member
Sep 25, 2019
191
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Warwick
I have the Cateye saddle mount (and light obvs.) mentioned above - it's a neat little solution, easily switched on when riding, right out of the way, secure clip fit that can be used while riding too. The light is usb rechargeable, side visable and blinks, pulses or full on. Very pleased with it through the wet and dark winter we've just had.
 

Gary

Old Tartan Bollocks
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I have this light mounted to my seat. Its automatic so it comes on when movement is detected. Also detects breaking so goes really bright when you break
Yeah. I know. I have two of them.
I think I mentioned it ;)
 

Zimmerframe

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Jun 12, 2019
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Also detects breaking so goes really bright when you break
Mine would be on all the time. I'm always breaking myself. How does it know ? Built in Cat scanner for bone fractures ? or it just measures extreme shocks ? Or it listens for loud shouts, followed by a period of silence followed by sobbing like a girl ? Still, it's a good idea, makes it easier for people to find me.
 

Jamy

Active member
Sep 24, 2019
206
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rotherham
Mine would be on all the time. I'm always breaking myself. How does it know ? Built in Cat scanner for bone fractures ? or it just measures extreme shocks ? Or it listens for loud shouts, followed by a period of silence followed by sobbing like a girl ? Still, it's a good idea, makes it easier for people to find me.
accelerometer if thats how you spell it
 

Akiwi

🐸 Kermit Elite 🐸
Feb 6, 2019
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Olching, Germany
I have permanently mounted a light on my bike that uses the bike battery. Worth every cent and the time involved installing it as it is always there, and always loaded.
At the front I have the B&M IQ-XE
At the back I have the Supernova E3. Awesome lights.
I made a bracket to mount the light on my Brake caliper.
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Gary

Old Tartan Bollocks
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Cool little light but that position would obscure the light from view quite badly on UK roads
 

R120

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Apr 13, 2018
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I really like what Haibike have done with the lighting options on their bike, where by you can buy rear lights that integrate into each seats stays and power off the battery
 

R120

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I suspect because if using a dropper post its very likely that the rear wheel will hit the bag when saddle is slammed on a full suspension bike.
 
Apr 26, 2020
109
80
Out west
I suspect because if using a dropper post its very likely that the rear wheel will hit the bag when saddle is slammed on a full suspension bike.
The small ones don't take much room but I could see that depending on how your bike is set up. I'm 6 feet and mostly legs so my bikes have a lot of seat tube showing.
 

Gary

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Like I said, I wouldn't really expect to have to explain this... but...
Tyre clearance with the post dropped as @R120 stated is one reason, another depending on what dropper post you have and how your saddle bag attaches to it is increasing wear and limiting function. I've seen far too many folk strap things around a dropper post limiting their dropper posts function or creating possible premature wear of the posts stanchion from friction or ruining their seals when from the bag/strap bottoming off the seal head when compressed.
This could be a non-issue depending on what bag you have or if you don't ever ride in rough terrain or poor conditions where dirt/grit could be rubbed between the bag/strap and the stanchion. But why risk it when there are plenty better options to fit tool bags to a bike?
Another reason is if your little bag sticks out further than your saddle you're decreasing crotch space when maneovering your arse behind/below the saddle. If you're never doing that it's possible you aren't really putting your dropper to its full potential.
And lastly you are adding needless weight to your bike in the worst possible place.

I also see plenty folk riding around on fairly expensive bikes with the forks on backwards tho so who am I to comment on your choice? ;)
 

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